U.S. patent application number 11/013567 was filed with the patent office on 2007-01-25 for marine vessel maneuvering supporting apparatus, marine vessel including the marine vessel maneuvering supporting apparatus, and marine vessel maneuvering supporting method.
Invention is credited to Hirotaka Kaji, Masaru Suemori.
Application Number | 20070017426 11/013567 |
Document ID | / |
Family ID | 34857499 |
Filed Date | 2007-01-25 |
United States Patent
Application |
20070017426 |
Kind Code |
A1 |
Kaji; Hirotaka ; et
al. |
January 25, 2007 |
Marine vessel maneuvering supporting apparatus, marine vessel
including the marine vessel maneuvering supporting apparatus, and
marine vessel maneuvering supporting method
Abstract
A marine vessel maneuvering supporting apparatus performs a
stationary marine vessel maneuvering support operation, the marine
vessel including a pair of propulsion systems which respectively
generate propulsive forces on a rear port side and a rear starboard
side of a hull, and a pair of steering mechanisms which
respectively change steering angles. The apparatus includes a
position detecting section which detects a position of the marine
vessel, a marine vessel maneuvering support starting command
section, a marine vessel maneuvering support starting position
storing section, a steering controlling section which controls the
steering angles of the respective steering mechanisms such that the
marine vessel has a turning angular speed of zero in response to
the marine vessel maneuvering support starting command, a target
propulsive force calculating section which calculates target
propulsive forces to be generated from the respective propulsion
systems, such that at least one of x- and y-coordinates of the
current marine vessel position is maintained substantially equal to
a corresponding one of x- and y-coordinates of the marine vessel
maneuvering support starting position, and a propulsive force
controlling section which controls the propulsion systems to attain
the target propulsive forces.
Inventors: |
Kaji; Hirotaka; (Shizuoka,
JP) ; Suemori; Masaru; (Shizuoka, JP) |
Correspondence
Address: |
YAMAHA HATSUDOKI KABUSHIKI KAISHA;C/O KEATING & BENNETT, LLP
8180 GREENSBORO DRIVE
SUITE 850
MCLEAN
VA
22102
US
|
Family ID: |
34857499 |
Appl. No.: |
11/013567 |
Filed: |
December 16, 2004 |
Current U.S.
Class: |
114/144RE |
Current CPC
Class: |
G05D 1/0208 20130101;
B63H 25/42 20130101; B63H 2020/003 20130101; B63J 99/00 20130101;
B63H 2025/026 20130101 |
Class at
Publication: |
114/144.0RE |
International
Class: |
B63H 25/00 20060101
B63H025/00 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 16, 2003 |
JP |
2003-418421 |
Claims
1. A marine vessel maneuvering supporting apparatus for performing
a stationary marine vessel maneuvering support operation to support
maneuvering of a marine vessel in a stationary state, the marine
vessel including a pair of propulsion systems which respectively
generate propulsive forces on a rear port side and a rear starboard
side of a hull of the marine vessel, and a pair of steering
mechanisms which respectively change steering angles defined by
directions of the propulsive forces gene rated by the respective
propulsion systems with respect to the hull, the marine vessel
maneuvering supporting apparatus comprising: a position detecting
section which detects a position of the marine vessel; a marine
vessel maneuvering support starting command section which outputs a
stationary marine vessel maneuvering support-starting command for
starting the stationary marine vessel maneuvering support
operation; a marine vessel maneuvering support starting position
storing section which stores a marine vessel maneuvering support
starting position that is defined by a marine vessel position
detected by the position detecting section in response to the
marine vessel maneuvering support starting command output from the
marine vessel maneuvering support starting command section; a
steering controlling section which controls the steering angles of
the respective steering mechanisms such that the marine vessel has
a turning angular speed of zero in response to the marine vessel
maneuvering support starting command output from the marine vessel
maneuvering support starting command section; a target propulsive
force calculating section which calculates, in response to the
marine vessel maneuvering support starting command output from the
marine vessel maneuvering support starting command section, target
propulsive forces to be generated from the respective propulsion
systems, based on a current marine vessel position detected by the
position detecting section, such that at least one of x- and
y-coordinates of the current marine vessel position defined with
respect to an x-axis defined along a center line of the hull
extending through a stem and a stern of the hull and a y-axis
extending substantially perpendicularly relative to the center line
is maintained substantially equal to a corresponding one of x- and
y-coordinates of the marine vessel maneuvering support starting
position stored in the marine vessel maneuvering support starting
position storing section; and a propulsive force controlling
section which controls the propulsion systems to attain the target
propulsive forces calculated by the target propulsive force
calculating section.
2. A marine vessel maneuvering supporting apparatus as set forth in
claim 1, wherein the target propulsive force calculating section
includes: a target control value calculating section which
calculates a target movement angle of the marine vessel with
respect to a stem direction of the hull and a target combined
propulsive force to be applied to the hull by the propulsion
systems, based on a deviation of the current marine vessel position
detected by the position detecting section from the marine vessel
maneuvering support starting position stored in the marine vessel
maneuvering support starting position storing section; and an
individual target propulsive force calculating section which
calculates the target propulsive forces to be generated from the
respective propulsion systems, based on the target movement angle
and the target combined propulsive force calculated by the target
control value calculating section.
3. A marine vessel maneuvering supporting apparatus as set forth in
claim 1, further comprising a target movement direction inputting
section which inputs one of a +x direction and a -x direction
defined along the x-axis and a +y direction and a -y direction
defined along the y-axis as the target movement direction of the
marine vessel, wherein the target propulsive force calculating
section calculates the target propulsive forces to be generated
from the respective propulsion systems such that the y-coordinate
of the current marine vessel position is maintained substantially
equal to the y-coordinate of the marine vessel maneuvering support
starting position if the target movement direction input by the
target movement direction inputting section is the +x direction or
the -x direction, and the x-coordinate of the current marine vessel
position is maintained substantially equal to the x-coordinate of
the marine vessel maneuvering support starting position if the
target movement direction input by the target movement direction
inputting section is the +y direction or the -y direction.
4. A marine vessel maneuvering supporting apparatus as set forth in
claim 3, wherein the target propulsive force calculating section
calculates the target propulsive forces to be generated from the
respective propulsion systems such that the x- and y-coordinates of
the current marine vessel position are maintained substantially
equal to the x- and y-coordinates of the marine vessel maneuvering
support starting position if nothing is input by the target
movement direction inputting section.
5. A marine vessel maneuvering supporting apparatus as set forth in
claim 1, further comprising a proximity state detecting section
which detects a proximity state of the marine vessel, wherein the
target propulsive force calculating section includes a proximity
state maintaining target propulsive force calculating section which
calculates the target propulsive forces to be generated from the
respective propulsion systems such that the marine vessel is
maintained in the proximity state when the proximity state
detecting section detects the proximity state.
6. A marine vessel maneuvering supporting apparatus as set forth in
claim 1, further comprising an angular speed detecting section
which detects the turning angular speed of the marine vessel,
wherein the steering controlling section includes a target steering
angle calculating section which calculates target steering angles
of the respective steering mechanisms such that the turning angular
speed detected by the angular speed detecting section is set at
zero.
7. A marine vessel maneuvering supporting apparatus for performing
a moorage marine vessel maneuvering support operation to support
maneuvering of a marine vessel for moorage of the marine vessel,
the marine vessel including a pair of propulsion systems which
respectively generate propulsive forces on a rear port side and a
rear starboard side of a hull of the marine vessel, and a pair of
steering mechanisms which respectively change steering angles
defined by directions of the propulsive forces generated by the
respective propulsion systems with respect to the hull, the marine
vessel maneuvering supporting apparatus comprising: a proximity
state detecting section which detects a proximity state of the
marine vessel; and a proximity state maintaining controlling
section which controls the steering mechanisms and the propulsion
systems so as to maintain the marine vessel in the proximity state
when the proximity state detecting section detects the proximity
state.
8. A marine vessel maneuvering supporting apparatus as set forth in
claim 7, wherein the proximity state maintaining controlling
section includes: a steering controlling section which controls the
steering angles of the respective steering mechanisms such that the
marine vessel has a turning angular speed of zero; a target
propulsive force calculating section which calculates target
propulsive forces to be generated from the respective propulsion
systems such that the marine vessel is maintained in the proximity
state detected by the proximity state detecting section; and a
propulsive force controlling section which controls the propulsion
systems so as to attain the target propulsive forces calculated by
the target propulsive force calculating section.
9. A marine vessel maneuvering supporting apparatus as set forth in
claim 8, further comprising an angular speed detecting section
which detects the turning angular speed of the marine vessel,
wherein the steering controlling section includes a target steering
angle calculating section which calculates target steering angles
of the respective steering mechanisms such that the turning angular
speed detected by the angular speed detecting section is set at
zero.
10. A marine vessel comprising: a hull; a pair of propulsion
systems which respectively generate propulsive forces on a rear
port side and a rear starboard side of the hull; a pair of steering
mechanisms which respectively change steering angles defined by
directions of the propulsive forces generated by the respective
propulsion systems with respect to the hull; and a marine vessel
maneuvering supporting apparatus for performing a stationary marine
vessel maneuvering support operation to support maneuvering of the
marine vessel in a stationary state, wherein the marine vessel
maneuvering supporting apparatus includes: a position detecting
section which detects a position of the marine vessel; a marine
vessel maneuvering support starting command section which outputs a
stationary marine vessel maneuvering support starting command for
starting the stationary marine vessel maneuvering support
operation; a marine vessel maneuvering support starting position
storing section which stores a marine vessel maneuvering support
starting position that is defined by a marine vessel position
detected by the position detecting section in response to the
marine vessel maneuvering support starting command output from the
marine vessel maneuvering support starting command section; a
steering controlling section which controls the steering angles of
the respective steering mechanisms such that the marine vessel has
a turning angular speed of zero in response to the marine vessel
maneuvering support starting command output from the marine vessel
maneuvering support starting command section; a target propulsive
force calculating section which calculates, in response to the
marine vessel maneuvering support starting command output from the
marine vessel maneuvering support starting command section, target
propulsive forces to be generated from the respective propulsion
systems, based on a current marine vessel position detected by the
position detecting section, such that at least one of x- and
y-coordinates of the current marine vessel position defined with
respect to an x-axis defined along a center line of the hull
extending through a stem and a stern of the hull and a y-axis
extending perpendicularly to the center line is maintained
substantially equal to a corresponding one of x- and y-coordinates
of the marine vessel maneuvering support starting position stored
in the marine vessel maneuvering support starting position storing
section; and a propulsive force controlling section which controls
the propulsion systems to attain the target propulsive forces
calculated by the target propulsive force calculating section.
11. A marine vessel comprising: a hull; a pair of propulsion
systems which respectively generate propulsive forces on a rear
port side and a rear starboard side of the hull; a pair of steering
mechanisms which respectively change steering angles defined by
directions of the propulsive forces generated by the respective
propulsion systems with respect to the hull; and a marine vessel
maneuvering supporting apparatus for performing a moorage marine
vessel maneuvering support operation to support maneuvering of the
marine vessel for moorage of the marine vessel, wherein the marine
vessel maneuvering supporting apparatus includes: a proximity state
detecting section which detects a proximity state of the marine
vessel; and a proximity state maintaining controlling section which
controls the steering mechanisms and the propulsion systems so as
to maintain the marine vessel in the proximity state when the
proximity state detecting section detects the proximity state.
12. A marine vessel maneuvering supporting method for performing a
stationary marine vessel maneuvering support operation to support
maneuvering of a marine vessel in a stationary state, the marine
vessel including a pair of propulsion systems which respectively
generate propulsive forces on a rear port side and a rear starboard
side of a hull of the marine vessel, and a pair of steering
mechanisms which respectively change steering angles defined by
directions of the propulsive forces generated by the respective
propulsion systems with respect to the hull, the method comprising
the steps of: storing a marine vessel maneuvering support starting
position at which the stationary marine vessel maneuvering support
operation is started in a marine vessel maneuvering support
starting position storing section; controlling the steering angles
of the respective steering mechanisms such that the marine vessel
has a turning angular speed of zero; calculating target propulsive
forces to be generated from the respective propulsion systems such
that at least one of x- and y-coordinates of a current position of
the marine vessel defined with respect to an x-axis defined along a
center line extending through a stem and a stern of the hull and a
y-axis extending substantially perpendicularly to the center fine
is maintained substantially equal to a corresponding one of x- and
y-coordinates of the marine vessel maneuvering support starting
position stored in the marine vessel maneuvering support starting
position storing section; and controlling the propulsion systems so
as to attain the calculated target propulsive forces.
13. A marine vessel maneuvering supporting method as set forth in
claim 12, wherein the target propulsive force calculating step
includes the steps of: calculating a target movement angle of the
marine vessel with respect to a stem direction of the hull and a
target combined propulsive force to be applied to the hull by the
propulsion systems, based on a deviation of the current marine
vessel position from the marine vessel maneuvering support starting
position stored in the marine vessel maneuvering support starting
position storing section; and calculating the target propulsive
forces to be generated from the respective propulsion systems,
based on the calculated target movement angle and the calculated
target combined propulsive force.
14. A marine vessel maneuvering supporting method as set forth in
claim 12, wherein the marine vessel further includes a target
movement direction inputting section which inputs one of a +x
direction and a -x direction defined along the x-axis and a +y
direction and a -y direction defined along the y-axis as the target
movement direction of the marine vessel, and the target propulsive
force calculating step includes the step of calculating the target
propulsive forces to be generated from the respective propulsion
systems such that the y-coordinate of the current marine vessel
position is maintained substantially equal to the y-coordinate of
the marine vessel maneuvering support starting position if the
target movement direction input by the target movement direction
inputting section is the +x direction or the -x direction, and the
x-coordinate of the current marine vessel position is maintained
substantially equal to the x-coordinate of the marine vessel
maneuvering support starting position if the target movement
direction input by the target movement direction inputting section
is the +y direction or the -y direction.
15. A marine vessel maneuvering supporting method as set forth in
claim 14, wherein the target propulsive force calculating step
includes the step of calculating the target propulsive forces to be
generated from the respective propulsion systems such that the x-
and y-coordinates of the current marine vessel position are
maintained substantially equal to the x- and y-coordinates of the
marine vessel maneuvering support starting position if nothing is
input by the target movement direction inputting section.
16. A marine vessel maneuvering supporting method as set forth in
claim 12, further comprising the step of detecting a proximity
state of the marine vessel, wherein the target propulsive force
calculating step includes the step of calculating the target
propulsive forces to be generated from the respective propulsion
systems such that the marine vessel is maintained in the proximity
state when the proximity state is detected.
17. A marine vessel maneuvering supporting method for performing a
moorage marine vessel maneuvering support operation to support
maneuvering of a marine vessel for moorage of the marine vessel,
the marine vessel including a pair of propulsion systems which
respectively generate propulsive forces on a rear port side and a
rear starboard side of a hull of the marine vessel, and a pair of
steering mechanisms which respectively change steering angles
defined by directions of the propulsive forces generated by the
respective propulsion systems with respect to the hull, the method
comprising the steps of: detecting a proximity state of the marine
vessel; and controlling the steering mechanisms and the propulsion
systems so as to maintain the marine vessel in the proximity state
when the proximity state is detected.
18. A marine vessel maneuvering supporting method as set forth in
claim 17, wherein the proximity state maintaining step includes the
steps of: controlling the steering angles of the respective
steering mechanisms such that the marine vessel has a turning
angular speed of zero; calculating target propulsive forces to be
generated from the respective propulsion systems such that the
marine vessel is maintained in the detected proximity state; and
controlling the propulsion systems so as to attain the calculated
target propulsive forces.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a marine vessel maneuvering
supporting apparatus which is applicable to a marine vessel having
at least one pair of propulsion systems provided at a stern
thereof, a marine vessel including the marine vessel maneuvering
supporting apparatus, and a marine vessel maneuvering supporting
method.
[0003] 2. Description of the Related Art
[0004] When a marine vessel travels toward or away from a wharf, a
lateral maneuvering operation is performed to laterally move the
hull of the marine vessel with the angular speed (stem turning
speed) of the hull being maintained constant (for example, at
zero). In general, large-scale marine vessels include a plurality
of small propulsion systems called "side thrusters" provided at a
stem and other locations of a hull to laterally move the hull. The
side thrusters each generate a propulsive force in a lateral
direction of the hull. Thus, the hull can be laterally moved toward
and away from the wharf by operating the side thrusters.
[0005] However, small-scale marine vessels, such as cruisers,
rarely include side thrusters because side thrusters cause various
problems, such as an increase in costs, a need to modify the design
of the hull to allow for installation of the side thrusters, and an
increase in fuel consumption due to an increase in drag of the
hull.
[0006] Cruisers and other leisure marine vessels are often operated
by unskilled beginners. However, the lateral maneuvering of the
small-scale marine vessels having no side thruster is very
difficult, thereby requiring skilled operation of the marine
vessel.
[0007] To this end, a marine vessel maneuvering apparatus which
includes port-side and starboard-side propulsion systems provided
at a stern of a marine vessel for facilitating the lateral
maneuvering operation is disclosed, for example, in Japanese Patent
No. 2810087. Japanese Patent No. 2810087 further discloses a
mechanism for adjusting the orientation of the port-side and the
starboard-side propulsion systems in accordance with each other,
and a mechanism for operating engine throttles of the port-side and
the starboard-side propulsion systems in accordance with each
other. More specifically, the marine vessel maneuvering apparatus
orients the port-side and starboard-side propulsion systems toward
the center of the hull and generates a forward propulsive force
from one of the propulsion systems and a reverse propulsive force
from the other propulsion system.
[0008] However, the marine vessel maneuvering apparatus is not
designed to calculate the directions and magnitudes of the
propulsive forces required to be generated by the port-side and
starboard-side propulsion systems for laterally moving the marine
vessel in a desired direction. Therefore, the operator must
manually operate the marine vessel for the lateral maneuvering
operation to laterally move the marine vessel in a parallel manner,
and thus must have a certain level of skill.
[0009] Further, the small-scale marine vessels are more likely to
be influenced by disturbances than the large-scale marine vessels.
More specifically, the instantaneous center (instantaneous rotation
center) of the hull observed when the marine vessel is turned is
easily changed by static disturbances such as the number and
positions of passengers and the weight and positions of cargoes.
Further, the instantaneous center is changed by dynamic
disturbances such as winds and waves.
[0010] However, the prior art disclosed in Japanese Patent No.
2810087 is based on the assumption that the instantaneous center is
fixed. Therefore, no consideration is given to the aforementioned
disturbances. In reality, the lateral maneuvering operation for
laterally moving the marine vessel toward and away from the wharf
requires a substantial level of skill even using the device
disclosed in this prior art.
[0011] Similarly, a marine vessel maneuvering operation for
maintaining the marine vessel at a fixed position requires a higher
level of marine vessel maneuvering skill. Therefore, it is
difficult for the beginners to maintain the marine vessel at a
fixed position when experiencing disturbances.
[0012] Thus, a so-called stationary marine vessel maneuvering
operation including the maneuvering operation for maintaining the
marine vessel at a fixed position and the maneuvering operation for
moving the marine vessel toward or away from a wharf requires a
higher level of marine vessel maneuvering skill.
SUMMARY OF THE INVENTION
[0013] To overcome the problems described above, preferred
embodiments of the present invention provide marine vessel
maneuvering supporting apparatuses and marine vessels which
facilitate the stationary marine vessel maneuvering operation.
[0014] Other preferred embodiments of the present invention provide
a marine vessel maneuvering supporting method which facilitates the
stationary marine vessel maneuvering operation.
[0015] A marine vessel maneuvering supporting apparatus according
to one preferred embodiment of the present invention performs a
stationary marine vessel maneuvering support operation to support
maneuvering of a marine vessel in a stationary state, the marine
vessel including a pair of propulsion systems which respectively
generate propulsive forces on a rear port side and a rear starboard
side of a hull of the marine vessel, and a pair of steering
mechanisms which respectively change steering angles defined by
directions of the propulsive forces generated by the respective
propulsion systems with respect to the hull. The apparatus includes
a position detecting section which detects a position of the marine
vessel, a marine vessel maneuvering support starting command
section which outputs a stationary marine vessel maneuvering
support starting command for starting the stationary marine vessel
maneuvering support operation, a marine vessel maneuvering support
starting position storing section which stores a marine vessel
maneuvering support starting position that is defined by a marine
vessel position detected by the position detecting section in
response to the marine vessel maneuvering support starting command
output from the marine vessel maneuvering support starting command
section, a steering controlling section which controls the steering
angles of the respective steering mechanisms such that the marine
vessel has a turning angular speed of zero in response to the
marine vessel maneuvering support starting command output from the
marine vessel maneuvering support starting command section, a
target propulsive force calculating section which calculates target
propulsive forces to be generated from the respective propulsion
systems, based on a current marine vessel position detected by the
position detecting section, such that at least one of x- and
y-coordinates of the current marine vessel position defined with
respect to an x-axis defined along a center line of the hull
extending through a stem and a stern of the hull and a y-axis
extending substantially perpendicularly relative to the center line
is maintained substantially equal to a corresponding one of x- and
y-coordinates of the marine vessel maneuvering support starting
position stored in the marine vessel maneuvering support starting
position storing section in response to the marine vessel
maneuvering support starting command output from the marine vessel
maneuvering support starting command section, and a propulsive
force controlling section which controls the propulsion systems to
attain the target propulsive forces calculated by the target
propulsive force calculating section.
[0016] With this arrangement, the turning angular speed is
maintained at zero to prevent the stem of the marine vessel from
turning. At the same time, the propulsive forces to be generated
from the respective propulsion systems are controlled such that at
least one of the x- and y-coordinates of the current marine vessel
position is maintained substantially equal to the corresponding one
of the x- and y-coordinates of the marine vessel maneuvering
support starting position. If the y-coordinate of the current
marine vessel position is maintained, the marine vessel is moved in
forward and reverse directions against disturbances without the
turning of the stem thereof. If the x-coordinate of the current
marine vessel position is maintained, the marine vessel is moved
leftward and rightward against disturbances without the turning of
the stem thereof. If the x- and y-coordinates of the current marine
vessel position are maintained, the marine vessel is maintained at
a fixed position on water. Thus, the marine vessel is moved forward
and reverse or leftward and rightward, or maintained at the fixed
position without the turning of the stem thereof. This facilitates
the stationary marine vessel maneuvering support operation to bring
the marine vessel into or out of contact with an object (e.g., a
pier, a wharf or another marine vessel) or to maintain the marine
vessel at a fixed position without skill.
[0017] For example, even an unskilled operator can easily perform a
marine vessel maneuvering operation to bring the marine vessel into
or out of contact with the object. Further, when the operator wants
to move the marine vessel by a very small distance for changing a
fishing point (for so-called trolling) or to maintain the marine
vessel at a fixed position against a tidal current or a wind during
fishing, the orientation of the hull can be easily and reliably
maintained. Thus, the maneuvering of the marine vessel is greatly
facilitated.
[0018] If an instantaneous center (instantaneous rotation center)
of the hull is considered to be fixed, the steering angles of the
respective steering mechanisms may be set at constant values
according to a target angular speed. More specifically, the
steering angles of the respective steering mechanisms may be
determined such that action lines along which the propulsive forces
are generated by the respective propulsion systems intersect each
other at the instantaneous center. In this case, the steering
angles are determined based on geometrical information related to
the hull and the propulsion systems. The geometrical information
includes, for example, positions of the respective propulsion
systems relative to the instantaneous center. In this case, the
relative positions may be defined by the positions of the
respective propulsion systems with respect to the center line of
the hull extending through the stem and the stern of the hull
(distances between the center line and propulsive force generating
positions at which the propulsive forces are generated) and a
distance from the instantaneous center to a midpoint between the
propulsive force generating positions of the respective propulsion
systems.
[0019] The instantaneous center is located, for example, on the
center line of the hull. For example, the respective propulsion
systems generate the propulsive forces at positions that are
symmetrical with respect to the center line. In this case, the
steering angles of the respective steering mechanisms may be
determined so as to be symmetrical with respect to the center
line.
[0020] The marine vessel may be a relatively small-scale marine
vessel such as a cruiser, a fishing boat, a water jet or a
watercraft.
[0021] The propulsion systems may be in the form of an outboard
motor, an inboard/outboard motor (a stern drive), an inboard motor,
or a water jet drive. The outboard motor includes a propulsion unit
provided outboard and having a motor and a propulsive force
generating member (propeller) and a steering mechanism which
horizontally turns the entire propulsion unit with respect to the
hull. The inboard/outboard motor includes a motor provided inboard,
and a drive unit provided outboard and having a propulsive force
generating member and a steering mechanism. The inboard motor
includes a motor and a drive unit provided inboard, and a propeller
shaft extending outward from the drive unit. In this case, a
steering mechanism is separately provided. The water jet drive is
such that water sucked from the bottom of the marine vessel is
accelerated by a pump and ejected from an ejection nozzle provided
at the stern of the marine vessel to provide a propulsive force. In
this case, the steering mechanism includes the ejection nozzle and
a mechanism for turning the ejection nozzle in a horizontal
plane.
[0022] If both of the propulsion systems includes a motor
(particularly an engine), the propulsive force controlling section
preferably controls throttle opening degrees of the engines of the
respective propulsion systems according to the target propulsive
forces. More specifically, the propulsive force controlling section
preferably includes a target engine speed calculating section which
calculates target engine speeds according to the target propulsive
forces, and a throttle opening degree controlling section which
controls the throttle opening degrees so as to attain the
calculated target engine speeds.
[0023] The motor may be an engine (internal combustion engine), an
electric motor or other suitable types of motors.
[0024] The target propulsive force calculating section preferably
includes a target control value calculating section which
calculates a target movement angle of the marine vessel with
respect to a stem direction of the hull and a target combined
propulsive force to be applied to the hull by the propulsion
systems, based on a deviation of the current marine vessel position
detected by the position detecting section from the marine vessel
maneuvering support starting position stored in the marine vessel
maneuvering support starting position storing section, and an
individual target propulsive force calculating section which
calculates the target propulsive forces to be generated from the
respective propulsion systems, based on the target movement angle
and the target combined propulsive force calculated by the target
control value calculating section.
[0025] With this arrangement, the target movement angle and the
target combined propulsive force are calculated according to the
deviation of the current marine vessel position and the marine
vessel maneuvering support starting position, and attained by
controlling the propulsive forces of the respective propulsion
systems. Thus, the stationary marine vessel maneuvering support
operation is performed.
[0026] The marine vessel maneuvering supporting apparatus
preferably further includes a target movement direction inputting
section which inputs one of a +x direction and a -x direction
defined along the x-axis and a +y direction and a -y direction
defined along the y-axis as the target movement direction of the
marine vessel. In this case, the target propulsive force
calculating section preferably calculates the target propulsive
forces to be generated from the respective propulsion systems such
that the y-coordinate of the current marine vessel position is
maintained substantially equal to the y-coordinate of the marine
vessel maneuvering support starting position if the target movement
direction input by the target movement direction inputting section
is the +x direction or the -x direction, and the x-coordinate of
the current marine vessel position is maintained substantially
equal to the x-coordinate of the marine vessel maneuvering support
starting position if the target movement direction input by the
target movement direction inputting section is the +y direction or
the -y direction.
[0027] Thus, the marine vessel is moved forward and reverse along
the x-axis or leftward and rightward along the y-axis depending
upon the input by the target movement direction inputting section.
Since the movement direction is limited to the aforementioned four
directions, the marine vessel maneuvering operation is
facilitated.
[0028] The target propulsive force calculating section preferably
calculates the target propulsive forces to be generated from the
respective propulsion systems such that the x- and y-coordinates of
the current marine vessel position are maintained substantially
equal to the x- and y-coordinates of the marine vessel maneuvering
support starting position if nothing is input by the target
movement direction inputting section. Thus, the marine vessel is
maintained at a fixed position on water despite the occurrence and
application of disturbances to the marine vessel.
[0029] The marine vessel maneuvering supporting apparatus
preferably further includes a proximity state detecting section
which detects a proximity state of the marine vessel. In this case,
the target propulsive force calculating section preferably includes
a proximity state maintaining target propulsive force calculating
section which calculates the target propulsive forces to be
generated from the respective propulsion systems such that the
marine vessel is maintained in the proximity state when the
proximity state detecting section detects the proximity state.
[0030] The proximity state herein means that the marine vessel is
located in contact with an object (e.g., a pier, a wharf, another
marine vessel or the like) or in close proximity to the object.
[0031] With this arrangement, the target propulsive forces are
determined so as to maintain the marine vessel in the proximity
state. Therefore, a moorage marine vessel maneuvering operation is
facilitated. That is, when the marine vessel is moored to the
object such as pier, wharf and the like, the marine vessel is
maintained in the proximity state. Therefore, crew members can
safely move between the marine vessel and the object, and safely
transfer cargoes between the marine vessel and the object. Since
the marine vessel is maintained in the proximity state, the marine
vessel is prevented from moving away from the object. Therefore, a
crew member can safely move onto the object from the marine vessel
and easily moor the marine vessel with a rope.
[0032] Similarly, when the marine vessel is to be moved away from
the object, a crew member can safely step onto the marine vessel
after unmooring the marine vessel from the object with the marine
vessel maintained in the proximity state.
[0033] A marine vessel maneuvering supporting apparatus according
to another preferred embodiment of the present invention performs a
moorage marine vessel maneuvering support operation to support
maneuvering of a marine vessel for moorage of the marine vessel,
the marine vessel including a pair of propulsion systems which
respectively generate propulsive forces on a rear port side and a
rear starboard side of a hull of the marine vessel, and a pair of
steering mechanisms which respectively change steering angles
defined by directions of the propulsive forces generated by the
respective propulsion systems with respect to the hull. The
apparatus includes a proximity state detecting section which
detects a proximity state of the marine vessel, and a proximity
state maintaining controlling section which controls the steering
mechanisms and the propulsion systems so as to maintain the marine
vessel in the proximity state when the proximity state detecting
section detects the proximity state.
[0034] With this arrangement, the marine vessel can easily be
moored to an object (e.g., a pier, a wharf or another marine
vessel) because the marine vessel is maintained in the proximity
state. In this state, crewmembers can safely move between the
marine vessel and the object, and safely transfer cargoes between
the marine vessel and the object. With the marine vessel maintained
in the proximity state, a mooring operation can safely be performed
to moor the marine vessel to the object with a rope. Similarly, a
crew member can safely step onto the marine vessel after unmooring
the marine vessel with the marine vessel maintained in the
proximity state.
[0035] The proximity state maintaining controlling section
preferably includes a steering controlling section which controls
the steering angles of the respective steering mechanisms such that
the marine vessel has a turning angular speed of zero, a target
propulsive force calculating section which calculates target
propulsive forces to be generated from the respective propulsion
systems such that the marine vessel is maintained in the proximity
state detected by the proximity state detecting section, and a
propulsive force controlling section which controls the propulsion
systems so as to attain the target propulsive forces calculated by
the target propulsive force calculating section. With this
arrangement, the marine vessel can be maintained in the proximity
state without turning a stem thereof. Therefore, the crew members
can more safely move between the marine vessel and the object.
[0036] The marine vessel maneuvering supporting apparatus
preferably further includes an angular speed detecting section
which detects the turning angular speed of the marine vessel. In
this case, the steering controlling section preferably includes a
target steering angle calculating section which calculates target
steering angles of the respective steering mechanisms such that the
turning angular speed detected by the angular speed detecting
section is set at zero.
[0037] With this arrangement, the marine vessel can be moved in a
desired direction with the target angular speed being kept
unchanged, even if an instantaneous center of the hull is changed.
Therefore, the marine vessel can easily be moved forward and
reverse or leftward and rightward in spite of disturbances
attributable to variations in loads on the hull and winds and
waves.
[0038] The target propulsive force calculating section preferably
calculates the target propulsive forces by using the target
steering angles calculated by the target steering angle calculating
section as the steering angles of the respective steering
mechanisms. Further, a steering angle detecting section which
detects at least one of the steering angles of the steering
mechanisms is preferably provided. That is, the target propulsive
force calculating section calculates the target propulsive forces
based on the steering angle detected by the steering angle
detecting section.
[0039] The target steering angle calculating section preferably
calculates the target steering angles of the respective steering
mechanisms such that action lines along which the propulsive forces
are generated by the respective propulsion systems intersect each
other on a center line of the hull extending through a stem and a
stern of the hull. With this arrangement, the steering angles of
the port-side and starboard-side steering mechanisms are
symmetrically set with respect to the center line. Therefore, the
steering angles are easily controlled.
[0040] Preferably, the target steering angle calculating section
calculates one of the target steering angles of the steering
mechanisms by adding a constant .phi..sub.c to a steering angle
correction value .psi. (.psi.>0) and calculates the other target
steering angle by subtracting the constant .phi..sub.c from the
steering angle correction value .psi. when an action point defined
by an intersection of the action lines is located outside the
center line.
[0041] With this arrangement, the target steering angles of the
respective steering mechanisms are determined by determining the
steering angle correction value .psi., whereby the computation for
the control is simplified. When the steering angle correction value
.psi. is .psi.=0, the action point is located on the center line of
the hull.
[0042] If the action point is spaced away from the propulsion
systems on a stem side, increased propulsive forces should be
generated from the respective propulsion systems to laterally move
the hull. However, each of the propulsion systems is limited in
their capability to generate the propulsive force. If it is
difficult to generate the propulsive forces in desired directions
even with the action point being located in a predetermined range
on the center line, the generation of the desired propulsive forces
is facilitated by locating the action point outside the center line
by setting the steering angle correction value to a value other
than zero.
[0043] A marine vessel according to a preferred embodiment of the
present invention includes a hull, a pair of propulsion systems
which respectively generate propulsive forces on a rear port side
and a rear starboard side of the hull, a pair of steering
mechanisms which respectively change steering angles defined by
directions of the propulsive forces generated by the respective
propulsion systems with respect to the hull, and a marine vessel
maneuvering supporting apparatus having the aforementioned
features.
[0044] With this marine vessel, the stationary marine vessel
maneuvering operation and the moorage marine vessel maneuvering
operation can easily be performed without requiring operator
skill.
[0045] A marine vessel maneuvering supporting method according to a
preferred embodiment of the present invention is a method for
performing a stationary marine vessel maneuvering support operation
to support maneuvering of a marine vessel in a stationary state,
the marine vessel including a pair of propulsion systems which
respectively generate propulsive forces on a rear port side and a
rear starboard side of a hull of the marine vessel, and a pair of
steering mechanisms which respectively change steering angles
defined by directions of the propulsive forces generated by the
respective propulsion systems with respect to the hull. The method
includes the steps of storing a marine vessel maneuvering support
starting position at which the stationary marine vessel maneuvering
support operation is started in a marine vessel maneuvering support
starting position storing section, controlling the steering angles
of the respective steering mechanisms such that the marine vessel
has a turning angular speed of zero, calculating target propulsive
forces to be generated from the respective propulsion systems such
that at least one of x- and y-coordinates of a current position of
the marine vessel defined with respect to an x-axis defined along a
center line extending through a stem and a stern of the hull and a
y-axis extending substantially perpendicularly relative to the
center line is maintained substantially equal to corresponding one
of x- and y-coordinates of the marine vessel maneuvering support
starting position stored in the marine vessel maneuvering support
starting position storing section, and controlling the propulsion
systems so as to attain the calculated target propulsive
forces.
[0046] In this method, the marine vessel can be moved forward and
reverse or leftward and rightward or maintained at a fixed position
while experiencing disturbances, and without turning the stem
thereof. Thus, the stationary marine vessel maneuvering operation
can be facilitated.
[0047] The target propulsive force calculating step includes the
steps of calculating a target movement angle of the marine vessel
with respect to a stem direction of the hull and a target combined
propulsive force to be applied to the hull by the propulsion
systems, based on a deviation of the current marine vessel position
from the marine vessel maneuvering support starting position stored
in the marine vessel maneuvering support starting position storing
section, and calculating the target propulsive forces to be
generated from the respective propulsion systems, based on the
calculated target movement angle and the calculated target combined
propulsive force.
[0048] Where the marine vessel includes a target movement direction
inputting section which inputs one of a +x direction and a -x
direction defined along the x-axis and a +y direction and a -y
direction defined along the y-axis as the target movement direction
of the marine vessel, the target propulsive force calculating step
preferably includes the step of calculating the target propulsive
forces to be generated from the respective propulsion systems such
that the y-coordinate of the current marine vessel position is
maintained substantially equal to the y-coordinate of the marine
vessel maneuvering support starting position if the target movement
direction input by the target movement direction inputting section
is the +x direction or the -x direction, and the x-coordinate of
the current marine vessel position is maintained substantially
equal to the x-coordinate of the marine vessel maneuvering support
starting position if the target movement direction input by the
target movement direction inputting section is the +y direction or
the -y direction. Thus, the marine vessel can easily be moved
forward and reverse or leftward and rightward.
[0049] The target propulsive force calculating step preferably
includes the step of calculating the target propulsive forces to be
generated from the respective propulsion systems such that the x-
and y-coordinates of the current marine vessel position are
maintained substantially equal to the x- and y-coordinates of the
marine vessel maneuvering support starting position if nothing is
input by the target movement direction inputting section. Thus, the
marine vessel is maintained at a fixed position on water.
[0050] The method preferably further includes the step of detecting
a proximity state of the marine vessel. In this case, the target
propulsive force calculating step preferably includes the step of
calculating the target propulsive forces to be generated from the
respective propulsion systems such that the marine vessel is
maintained in the proximity state when the proximity state is
detected. Thus, the marine vessel is maintained in the proximity
state for moorage thereof by controlling the propulsion
systems.
[0051] A marine vessel maneuvering supporting method according to
another preferred embodiment of the present invention is a method
for performing a moorage marine vessel maneuvering support
operation to support maneuvering of a marine vessel for moorage of
the marine vessel, the marine vessel including a pair of propulsion
systems which respectively generate propulsive forces on a rear
port side and a rear starboard-side of a hull of the marine vessel,
and a pair of steering mechanisms which respectively change
steering angles defined by directions of the propulsive forces
generated by the respective propulsion systems with respect to the
hull. The method includes the steps of detecting a proximity state
of the marine vessel, and controlling the steering mechanisms and
the propulsion systems so as to maintain the marine vessel in the
proximity state when the proximity state is detected. In this
method, the marine vessel is maintained in the proximity state for
moorage thereof by controlling the propulsion systems.
[0052] The proximity state maintaining step includes the steps of
controlling the steering angles of the respective steering
mechanisms such that the marine vessel has a turning angular speed
of zero, calculating target propulsive forces to be generated from
the respective propulsion systems such that the marine vessel is
maintained in the detected proximity state, and controlling the
propulsion systems so as to attain the calculated target propulsive
forces. Thus, the marine vessel can be maintained in the proximity
state for moorage thereof without turning a stem thereof.
[0053] The foregoing and other elements, features, steps,
characteristics and advantages of the present invention will become
more apparent from the following detailed description of the
preferred embodiments with reference to the attached drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0054] FIG. 1 is a schematic diagram illustrating a marine vessel
according to one preferred embodiment of the present invention;
[0055] FIG. 2 is a schematic diagram showing marine vessel movement
directions in which the marine vessel is moved in a stationary
marine vessel maneuvering support mode;
[0056] FIG. 3A is a schematic diagram illustrating an exemplary
operation to be performed in a moorage support mode;
[0057] FIG. 3B is a schematic diagram illustrating another
exemplary operation to be performed in the moorage support
mode;
[0058] FIG. 3C is a schematic diagram illustrating further another
exemplary operation to be performed in the moorage support
mode;
[0059] FIG. 3D is a schematic diagram illustrating still another
exemplary operation to be performed in the moorage support
mode;
[0060] FIG. 4 is a schematic sectional view illustrating an
outboard motor;
[0061] FIG. 5 is a block diagram illustrating a marine vessel
maneuvering supporting apparatus for controlling running of the
marine vessel;
[0062] FIG. 6 is a diagram illustrating an operation for moving the
marine vessel such that the orientation of a stem of the marine
vessel kept remains unchanged;
[0063] FIG. 7 is a diagram illustrating an operation for
horizontally moving the marine vessel substantially perpendicularly
relative to a center line of the marine vessel;
[0064] FIG. 8 is a schematic diagram for explaining a steering
controlling operation;
[0065] FIG. 9 is a schematic diagram for explaining the principle
of operation for locating an action point outside the center
line;
[0066] FIG. 10 is a block diagram illustrating the functions of a
stationary marine vessel maneuvering support controlling
section;
[0067] FIG. 11 is a flowchart of an operation to be performed by
the stationary marine vessel maneuvering support controlling
section in the stationary marine vessel maneuvering support
mode;
[0068] FIG. 12 is a flowchart of an operation to be per formed by
the stationary marine vessel maneuvering support controlling
section in the moorage support mode;
[0069] FIG. 13 is a block diagram illustrating the functions of a
throttle controlling section and a shift controlling section,
particularly, for explaining control operations to be performed by
the throttle controlling section and the shift controlling section
in the stationary marine vessel maneuvering support mode and the
moorage support mode;
[0070] FIG. 14 is a timing chart of PWM operations to be performed
by a port-side shift control module and a starboard-side shift
control module;
[0071] FIG. 15 is a block diagram illustrating the functions of a
steering controlling section, particularly, for explaining a
control operation to be performed by the steering controlling
section in the stationary marine vessel maneuvering support mode
and the moorage support mode;
[0072] FIG. 16 is a flow chart for explaining a throttle
controlling operation;
[0073] FIG. 17 is a flow chart for explaining an operation for
controlling a shift mechanism of a port-side outboard motor;
[0074] FIG. 18 is a flow chart for explaining the control operation
to be performed by the steering controlling section in the
stationary marine vessel maneuvering support mode and the moorage
support mode;
[0075] FIG. 19 is a flow chart for explaining an outboard motor
stop detecting operation; and
[0076] FIG. 20 is a block diagram illustrating a second preferred
embodiment of the present invention, particularly illustrating an
engine speed calculating module that is preferably used in place of
a target engine speed calculating module shown in FIG. 13.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0077] FIG. 1 is a schematic diagram illustrating a marine vessel 1
according to one preferred embodiment of the present invention. The
marine vessel 1 is preferably a relatively small-scale marine
vessel, such as a cruiser or a boat, and includes a pair of
outboard motors 11, 12 attached to a stern (transom) 3 of a hull 2.
The outboard motors 11, 12 are positioned laterally symmetrically
with respect to a center line 5 of the hull 2 extending through the
stern 3 and a stem 4 of the hull 2. That is, the outboard motor 11
is attached to a rear port-side portion of the hull 2, while the
outboard motor 12 is attached to a rear starboard-side portion of
the hull 2. The outboard motor 11 and the outboard motor 12 will
hereinafter be referred to as "port-side outboard motor 11" and
"starboard-side outboard motor 12", respectively, to differentiate
therebetween. Electronic control units 13 and 14 (hereinafter
referred to as "outboard motor ECU 13" and "outboard motor ECU 14",
respectively) are incorporated in the port-side outboard motor 11
and the starboard-side outboard motor 12, respectively.
[0078] The marine vessel 1 includes a control console 6 provided on
a deck thereof for controlling the marine vessel 1. The control
console 6 includes, for example, a steering operational section 7
for performing a steering operation, and a throttle operational
section 8 for controlling the outputs of the outboard motors 11,
12. The control console 6 further includes a stationary marine
vessel maneuvering support starting button 15 for staring a
stationary marine vessel maneuvering support controlling operation
to support maneuvering of the marine vessel 1 in a stationary state
(stationary marine vessel maneuvering operation), a cross button 16
(movement direction inputting section) for moving the marine vessel
1 at a very low speed in any of four directions (forward, reverse,
rightward and leftward directions), and a moorage support starting
button 17 for starting a moorage support controlling operation to
support moorage of the marine vessel 1 in a proximity state.
[0079] The stationary marine vessel maneuvering operation herein
includes a marine vessel approach maneuvering operation for moving
the marine vessel 1 toward an object (e.g., a pier, a wharf or
another marine vessel), a marine vessel departure maneuvering
operation for moving the marine vessel 1 away from the object, and
a fixed position marine vessel maintaining operation for
maintaining the marine vessel 1 at a fixed position on water.
[0080] The steering operational section 7 includes a steering wheel
7a (operational member). The throttle operational section 8
includes throttle levers 8a, 8b for the port-side outboard motor 11
and the starboard-side outboard motor 12. The cross button 16
includes a forward movement button 16A for forward movement of the
marine vessel 1, a reverse movement button 16B for reverse movement
of the marine vessel 1, a leftward movement button 16C for leftward
movement of the marine vessel 1, and a rightward movement button
16D for rightward movement of the marine vessel 1.
[0081] The operational signals of the operational sections 7, 8
provided on the control console 6 are input as electric signals to
a marine vessel running controlling apparatus 20, for example, via
a LAN (local area network, hereinafter referred to as an "inboard
LAN") provided in the hull 2. Similarly, the output signals of the
stationary marine vessel maneuvering support starting button 15,
the cross button 16 and the moorage support starting button 17 are
input to the marine vessel running controlling apparatus 20 via the
inboard LAN. The marine vessel running controlling apparatus 20
includes an electronic control unit (ECU) including a
microcomputer, and functions as a propulsive force controlling
apparatus for propulsive force control and as a steering
controlling apparatus for steering control. A yaw rate sensor 9
(angular speed detecting section) for detecting the angular speed
(yaw rate or stem turning speed) of the hull 2 outputs an angular
speed signal, which is also input to the marine vessel running
controlling apparatus 20 via the inboard LAN. Further, a GPS
(Global Positioning System) 10 (position detecting section) for
detecting the position of the marine vessel 1 outputs a position
signal, which is also input to the marine vessel running
controlling apparatus 20 via the inboard LAN.
[0082] A plurality of proximity sensors 18 which detect the
proximity state are provided on peripheral portions of the hull 2
to be brought into contact with the object (the pier, the wharf or
another marine vessel). Each of the proximity sensors 18 may be a
contact sensor such as a limit switch or a pressure sensor which
detects contact with the object, or a distance sensor such as an
ultrasonic sensor which detects a distance from the object. The
output signals of the respective proximity sensors 18 are also
input to the marine vessel running controlling apparatus 20 via the
inboard LAN.
[0083] The marine vessel running controlling apparatus 20
communicates with the outboard motor ECUs 13, 14 via the inboard
LAN. More specifically, the marine vessel running controlling
apparatus 20 acquires engine speeds (rotational speeds of motors)
NL, NR of the outboard motors 11, 12 and steering angles .phi.L,
.phi.R of the outboard motors 11, 12 indicating the orientations of
the outboard motors 11, 12 from the outboard motor ECUs 13, 14. The
marine vessel running controlling apparatus 20 applies data
including target steering angles .phi.L.sub.t, .phi.R.sub.t
(wherein a suffix "t" hereinafter means "target"), target throttle
opening degrees, target shift positions (forward drive, neutral and
reverse drive positions) and target trim angles to the outboard
motor ECUs 13, 14.
[0084] In this preferred embodiment, the marine vessel running
controlling apparatus 20 has a control mode to be switched between
various modes including an ordinary running mode in which the
outboard motors 11, 12 are controlled according to the operations
of the steering operational section 7 and the throttle operational
section 8, a stationary marine vessel maneuvering support mode in
which the outboard motors 11, 12 are controlled according to the
operation of the cross button 16, and a moorage support mode in
which the marine vessel is moored. The marine vessel running
controlling apparatus 20 is preferably usually in the ordinary
running mode.
[0085] In the ordinary running mode, the marine vessel running
controlling apparatus 20 controls the outboard motors 11, 12
according to the operation of the steering wheel 7a such that the
steering angles .phi.L, .phi.R are substantially equal to each
other. That is, the outboard motors 11, 12 generate propulsive
forces that are parallel with each other. In the ordinary running
mode, the marine vessel running controlling apparatus 20 determines
the target throttle opening degrees and the target shift positions
of the outboard motors 11, 12 according to the operation positions
and directions of the throttle levers 8a, 8b. The throttle levers
8a, 8b are each inclinable in forward and reverse directions. When
an operator inclines the throttle lever 8a forward from a neutral
position by a certain amount, the marine vessel running controlling
apparatus 20 sets the target shift position of the port-side
outboard motor 11 at the forward drive position. When the operator
inclines the throttle lever 8a further forward, the marine vessel
running controlling apparatus 20 sets the target throttle opening
degree of the port-side outboard motor 11 according to the position
of the throttle lever 8a. On the other hand, when the operator
inclines the throttle lever 8a in the reverse direction by a
certain amount, the marine vessel running controlling apparatus 20
sets the target shift position of the port-side outboard motor 11
at the reverse drive position. When the operator inclines the
throttle lever 8a further in the reverse direction, the marine
vessel running controlling apparatus 20 sets the target throttle
opening degree of the port-side outboard motor 11 according to the
position of the throttle lever 8a. Similarly, the marine vessel
running controlling apparatus 20 sets the target shift position and
the target throttle opening degree of the starboard-side outboard
motor 12 according to the operation of the throttle lever 8b.
[0086] Upper portions of the throttle levers 8a, 8b are bent toward
each other to constitute generally horizontal holders. With this
arrangement, the operator can simultaneously operate the throttle
levers 8a, 8b to control the outputs of the outboard motors 11, 12
with the throttle opening degrees of the port-side and
starboard-side outboard motors 11, 12 being maintained
substantially the same.
[0087] When the operator operates the stationary marine vessel
maneuvering support starting button 15, the control mode of the
marine vessel running controlling apparatus 20 is switched to the
stationary marine vessel maneuvering support mode. In the
stationary marine vessel maneuvering support mode, the marine
vessel running controlling apparatus 20 sets the target steering
angles .phi.L.sub.t, .phi.R.sub.t, the target shift positions and
the target throttle opening degrees of the port-side and
starboard-side outboard motors 11, 12 according to the operation of
the cross button 16.
[0088] In the stationary marine vessel maneuvering support mode, as
shown in FIG. 2, the movement directions of the marine vessel 1 are
limited to four directions including a forward direction (+x
direction), a reverse direction (-x direction), a leftward
direction (+y direction) and a rightward direction (-y direction).
That is, the marine vessel 1 is controlled with the orientation of
the stem thereof being kept unchanged. In this state, the marine
vessel 1 is moved forward when the forward movement button 16A is
operated, and moved in the reverse direction when the reverse
movement button 16B is operated. Further, the marine vessel 1 is
moved leftward when the leftward movement button 16C is operated,
and moved rightward when the rightward movement button 16D is
operated. In any of these cases, the movement direction of the
marine vessel 1 on water is kept unchanged despite disturbances
such as winds and waves. When none of the buttons 16A to 16D is
operated, a fixed position maintaining control operation is
preferably performed to maintain the marine vessel 1 at a fixed
position despite the disturbances.
[0089] On the other hand, when the operator operates the moorage
support starting button 17, the control mode of the marine vessel
running controlling apparatus 20 is switched to the moorage support
mode. In the moorage support mode, the marine vessel running
controlling apparatus 20 sets the target steering angles
.phi.L.sub.t, .phi.R.sub.t, the target shift positions and the
target throttle opening degrees of the port-side and starboard-side
outboard motors 11, 12 so as to maintain the proximity state
detected by the proximity sensors 18.
[0090] FIGS. 3A to 3D are diagrams illustrating exemplary
operations to be performed in the moorage support mode.
[0091] FIG. 3A illustrates a case where the marine vessel 1 is
moored to a pier 150 (object) with its port side 1L opposed to the
pier 150. In this case, two proximity sensors 18 (indicated by
black circles) provided on the port side 1L of the marine vessel 1L
detect the proximity state. The outboard motors 11, 12 generate
propulsive forces for moving the marine vessel 1 leftward toward
the pier 150 such that the proximity sensors 18 continuously detect
the proximity state. Thus, the marine vessel 1 is pressed toward
the pier 150 with the port side 1L thereof in contact with the pier
150. Since the marine vessel 1 is prevented from moving away from
the pier 150, the operator and other crew members of the marine
vessel 1 can safely step off the marine vessel 1 onto the pier 150.
Further, the marine vessel 1 can easily be moored to the pier 150
with a rope.
[0092] FIG. 3B illustrates a case where the marine vessel 1 is
moored to the pier 150 with the stem 4 thereof opposed to the pier
150. In this case, a proximity sensor 18 (indicated by a black
circle) provided at the stem 4 detects the proximity state. The
outboard motors 11, 12 generate propulsive forces for moving the
marine vessel 1 forward toward the pier 150 such that the proximity
sensor 18 continuously detects the proximity state. Thus, the stem
4 of the marine vessel 1 is moved toward and into contact with the
pier 150. Therefore, the operator and other crew members of the
marine vessel 1 can safely step off the marine vessel 1 onto the
pier 150, and the marine vessel 1 can easily be moored to the pier
150 with a rope.
[0093] Where the object to be approached by the marine vessel 1 is
a larger-scale marine vessel such as a tugboat, for example, the
marine vessel 1 can be moved toward and into contact with the
larger-scale marine vessel in the aforementioned manner. Thus, crew
members can safely move between the marine vessel 1 and the
larger-scale marine vessel, and easily transfer cargoes between the
marine vessel 1 and the larger-scale marine vessel.
[0094] In any case, the marine vessel 1 is continuously pressed
toward the object when the control is continued in the moorage
support mode. Therefore, the rope is not necessarily required for
the moorage.
[0095] FIGS. 3C and 3D illustrate cases where the marine vessel 1
is moored to another marine vessel 1A having substantially the same
size as the marine vessel 1. Where the marine vessels 1, 1A have
substantially the same construction, the marine vessels 1, 1A are
preferably both controlled in the moorage support mode. Thus, the
marine vessels 1, 1A are moved toward and into contact with each
other. In FIG. 3C, the outboard motors 11, 12 generate propulsive
forces for moving the marine vessels 1, 1A toward each other such
that the starboard side of the marine vessel 1 and the port side of
the marine vessel 1A move into contact with each other in the
vicinity of their stems. In FIG. 3D, the outboard motors 11, 12
generate propulsive forces for moving the marine vessels 1, 1A
toward each other in substantially parallel relation with the
starboard side of the marine vessel 1 and the port side of the
marine vessel 1A so as to move into contact with each other.
[0096] With the marine vessels 1, 1A moored to each other, crew
members can move between the marine vessels 1 and 1A, and transfer
cargoes between the marine vessels 1 and 1A. The marine vessels 1,
1A can be moored to each other in either of the moorage states
shown in FIGS. 3C and 3D depending upon the constructions of the
marine vessels 1, 1A and the positions of the cargoes.
[0097] In either case of FIGS. 3C and 3D, the marine vessels 1, 1A
can be moored to each other by continuing the control in the
moorage support mode. Further, the marine vessels 1, 1A can be
moored with a rope while the marine vessels 1, 1A are pressed
toward each other with the control thereof in the moorage support
mode. After the moorage with the rope, the control of the outboard
motors 11, 12 in the moorage support mode may be terminated.
[0098] It is preferred to control the outboard motors 11, 12 in the
moorage support mode when the marine vessel 1 is unmoored. Thus,
the marine vessel 1 can be unmoored while being assuredly
maintained in the proximity state by the propulsive forces
generated from the outboard motors 11, 12. Therefore, a crew member
can safely step onto the marine vessel 1 after unmooring the marine
vessel 1.
[0099] FIG. 4 is a schematic sectional view illustrating the common
construction of the outboard motors 11, 12. The outboard motors 11,
12 each include a propulsion unit 30, and an attachment mechanism
31 for attaching the propulsion unit 30 to the hull 2. The
attachment mechanism 31 includes a clamp bracket 32 detachably
fixed to the transom of the hull 2, and a swivel bracket 34
connected to the clamp bracket 32 pivotally about a tilt shaft 33
(horizontal pivot axis). The propulsion unit 30 is attached to the
swivel bracket 34 pivotally about a steering shaft 35. Thus, the
steering angle (which is equivalent to an angle defined by the
direction of the propulsive force with respect to the center line
of the hull 2) is changed by pivoting the propulsion unit 30 about
the steering shaft 35. Further, the trim angle of the propulsion
unit 30 (which is equivalent to an angle defined by the direction
of the propulsive force with respect to a horizontal plane) is
changed by pivoting the swivel bracket 34 about the tilt shaft
33.
[0100] The propulsion unit 30 has a housing which includes a top
cowling 36, an upper case 37 and a lower case 38. An engine 39
(drive source) is provided in the top cowling 36 with an axis of a
crank shaft thereof extending vertically. A drive shaft 41 for
transmitting power is coupled to a lower end of the crank shaft of
the engine 39, and vertically extends through the upper case 37
into the lower case 38.
[0101] A propeller 40 defining a propulsive force generating member
is rotatably attached to a lower rear portion of the lower case 38.
A propeller shaft 42 (rotation shaft) of the propeller 40 extends
horizontally in the lower case 38. The rotation of the drive shaft
41 is transmitted to the propeller shaft 42 via a shift mechanism
43 (clutch mechanism).
[0102] The shift mechanism 43 includes a beveled drive gear 43a
fixed to a lower end of the drive shaft 41, a beveled forward drive
gear 43b rotatably provided on the propeller shaft 42, a beveled
reverse drive gear 43c rotatably provided on the propeller shaft
42, and a dog clutch 43d provided between the forward drive gear
43b and the reverse drive gear 43c.
[0103] The forward drive gear 43b is meshed with the drive gear 43a
from a forward side, and the reverse drive gear 43c is meshed with
the drive gear 43a from a reverse side. Therefore, the forward
drive gear 43b and the reverse drive gear 43c rotate in opposite
directions when engaged with the drive gear 43a.
[0104] On the other hand, the dog clutch 43d is in spline
engagement with the propeller shaft 42. That is, the dog clutch 43d
is axially slidable with respect to the propeller shaft 42, but is
not rotatable relative to the propeller shaft 42. Therefore, the
dog clutch 43d is rotatable together with the propeller shaft
42.
[0105] The dog clutch 43 disslidable on the propeller shaft 42 by
pivotal movement thereof about a shift rod 44 that extends
vertically parallel to the drive shaft 41. Thus, the dog clutch 43d
is shifted to a forward drive position at which it is engaged with
the forward drive gear 43b, a reverse drive position at which it is
engaged with the reverse drive gear 43c, or a neutral position at
which it is not engaged with either the forward drive gear 43b or
the reverse drive gear 43c.
[0106] When the dog clutch 43d is in the forward drive position,
the rotation of the forward drive gear 43b is transmitted to the
propeller shaft 42 via the dog clutch 43d with virtually no
slippage between the dog clutch 43d and the propeller shaft 42.
Thus, the propeller 40 is rotated in one direction (in a forward
drive direction) to generate a propulsive force in a direction for
moving the hull 2 forward. On the other hand, when the dog clutch
43d is in the reverse drive position, the rotation of the reverse
drive gear 43c is transmitted to the propeller shaft 42 via the dog
clutch 43d with virtually no slippage between the dog clutch 43d
and the propeller shaft 42. The reverse drive gear 43c is rotated
in a direction opposite to that of the forward drive gear 43b, as
mentioned above. The propeller 40 is therefore rotated in an
opposite direction (in a reverse drive direction). Thus, the
propeller 40 generates a propulsive force in a direction for moving
the hull 2 reverse. When the dog clutch 43d is at the neutral
position, the rotation of the drive shaft 41 is not transmitted to
the propeller shaft 42. That is, transmission of a driving force
between the engine 39 and the propeller 40 is prevented, such that
no propulsive force is generated in either of the forward and
reverse directions.
[0107] A starter motor 45 for starting the engine 39 is connected
to the engine 39. The starter motor 45 is controlled by the
outboard motor ECU 13, 14. The propulsive unit 30 further includes
a throttle actuator 51 for actuating a throttle valve 46 of the
engine 39 in order to change the throttle opening degree to change
the intake air amount of the engine 39. The throttle actuator 51
may be an electric motor. The operation of the throttle actuator 51
is controlled by the outboard motor ECU 13, 14. The engine 39
includes an engine speed detecting section 48 for detecting the
rotation of the crank shaft to detect the engine speed NL, NR of
the engine 39.
[0108] A shift actuator 52 (clutch actuator) for changing the shift
position of the dog clutch 43d is provided in cooperation with the
shift rod 44. The shift actuator 52 is, for example, an electric
motor, and its operation is controlled by the outboard motor ECU
13, 14.
[0109] Further, a steering actuator 53 which includes, for example,
a hydraulic cylinder and is controlled by the outboard motor ECU
13, 14 is connected to a steering rod 47 fixed to the propulsion
unit 30. By driving the steering actuator 53, the propulsion unit
30 is pivoted about the steering shaft 35 for a steering operation.
The steering actuator 53, the steering rod 47 and the steering
shaft 35 define a steering mechanism 50. The steering mechanism 50
includes a steering angle sensor 49 for detecting the steering
angle .phi.L, .phi.R.
[0110] A trim actuator (tilt trim actuator) 54 which includes, for
example, a hydraulic cylinder and is controlled by the outboard
motor ECU 13, 14 is provided between the clamp bracket 32 and the
swivel bracket 34. The trim actuator 54 pivots the propulsion unit
30 about the tilt shaft 33 by pivoting the swivel bracket 34 about
the tilt shaft 33. Thus, the trim angle of the propulsion unit 30
can be adjusted.
[0111] FIG. 5 is a block diagram illustrating a marine vessel
maneuvering supporting apparatus for controlling the running of the
marine vessel 1. The marine vessel running controlling apparatus 20
includes a throttle controlling section 21 which issues command
signals regarding the target throttle opening degrees for
controlling the throttle actuators 51 of the port-side and
starboard-side outboard motors 11, 12, a shift controlling section
22 (clutch controlling section) which issues command signals of the
target shift positions for controlling the shift actuators 52 of
the outboard motors 11, 12, a steering controlling section 23 which
issues command signals of the target steering angles .phi.L.sub.t,
.phi.R.sub.t for controlling the steering actuators 53 of the
outboard motors 11, 12, and a trim angle controlling section 24
which issues command signals of the target trim angles for
controlling the trim actuators 54 of the outboard motors 11, 12.
The functions of each of these controlling sections 21 to 24 may be
provided by a predetermined software-based process performed by the
microcomputer provided in the marine vessel running controlling
apparatus 20.
[0112] The command signals generated by the respective controlling
sections 21 to 24 are applied to the outboard motor ECUs 13, 14 via
an interface (I/F) 25. The outboard motor ECUs 13, 14 control the
actuators 51 to 54 based on the applied command signals.
[0113] The outboard motor ECUs 13, 14 respectively apply the engine
speeds NL, NR detected by the engine speed detecting sections 48
and the steering angles .phi.L, .phi.R detected by the steering
angle sensors 49 to the marine vessel running controlling apparatus
20 via the interface 25. More specifically, the engine speeds NL,
NR are applied to the throttle controlling section 21, and the
steering angles .phi.L, .phi.R are applied to the steering
controlling section 23. The steering angles .phi.L, .phi.R may also
be applied to the throttle controlling section 21 from the steering
controlling section 23. The target steering angles .phi.L.sub.t,
.phi.R.sub.t may be applied instead of the steering angles .phi.L,
.phi.R to the throttle controlling section 21 from the steering
controlling section 23.
[0114] On the other hand, signals from the steering operational
section 7, the throttle operational section 8, the yaw rate sensor
9, the GPS 10, the stationary marine vessel maneuvering support
starting button 15, the cross button 16, the moorage support
starting button 17 and the proximity sensors 18 are input to the
marine vessel running controlling apparatus 20 via an interface
(I/F) 26. More specifically, signals from the steering operational
section 7 are input to the steering controlling section 23 for
calculating the target steering angles .phi.L.sub.t, .phi.R.sub.t.
Signals indicating the magnitudes of the target propulsive forces
are input from the throttle operational section 8 to the throttle
controlling section 21, and signals indicating the directions of
the propulsive forces are input from the throttle operational
section 8 to the shift controlling section 22. The angular speed
.omega. detected by the yaw rate sensor 9 is input to the steering
controlling section 23.
[0115] Output signals of the GPS 10, the stationary marine vessel
maneuvering support starting button 15, the cross button 16, the
moorage support starting button 17 and the proximity sensors 18 are
input to a stationary marine vessel maneuvering support controlling
section 27.
[0116] When the operation of the stationary marine vessel
maneuvering support starting button 15 is detected, the stationary
marine vessel maneuvering support controlling section 27 switches
the control mode of the marine vessel running controlling apparatus
20 to the stationary marine vessel maneuvering support mode. In the
stationary marine vessel maneuvering support mode, a target
combined propulsive force TG.sub.t to be generated by the port-side
and starboard-side outboard motors 11, 12 and a target movement
angle .theta..sub.t of the marine vessel 1 are calculated according
to the input from the GPS 10 and the cross button 16 by the
stationary marine vessel maneuvering support controlling section
27, and applied to the throttle controlling section 21. At the same
time, a target angular speed (target stem turning speed)
.omega..sub.t of the marine vessel 1 is set at zero by the
stationary marine vessel maneuvering support controlling section
27, and input to the steering controlling section 23 in the
stationary marine vessel maneuvering support mode.
[0117] When the operation of the moorage support starting button 17
is detected, the stationary marine vessel maneuvering support
controlling section 27 switches the control mode of the marine
vessel running controlling apparatus 20 to the moorage support
mode. In the moorage support mode, the target combined propulsive
force TG.sub.t to be generated by the port-side and starboard-side
outboard motors 11, 12 and the target movement angle .theta..sub.t
of the marine vessel 1 are calculated based on the output signals
of the proximity sensors 18 to maintain the marine vessel 1 in the
proximity state by the stationary marine vessel maneuvering support
controlling section 27, and applied to the throttle controlling
section 21. At the same time, the target angular speed (target stem
turning speed) .omega..sub.t of the marine vessel 1 is set at zero
by the stationary marine vessel maneuvering support controlling
section 27, and input to the steering controlling section 23 in the
moorage support mode.
[0118] When the operation of the steering wheel 7a or the operation
of the throttle lever 8a or 8b is detected in the stationary marine
vessel maneuvering support mode, the stationary marine vessel
maneuvering support controlling section 27 switches the control
mode of the marine vessel running controlling apparatus 20 to the
ordinary running mode from the stationary marine vessel maneuvering
support mode. When the operation of the moorage support starting
button 17 is detected in the stationary marine vessel maneuvering
support mode, the stationary marine vessel maneuvering support
controlling section 27 switches the control mode of the marine
vessel running controlling apparatus 20 to the moorage support mode
from the stationary marine vessel maneuvering support mode.
[0119] When the operation of the steering wheel 7a or the operation
of the throttle lever 8a or 8b is detected in the moorage support
mode, the stationary marine vessel maneuvering support controlling
section 27 switches the control mode of the marine vessel running
controlling apparatus 20 to the ordinary running mode from the
moorage support mode. When the operation of the stationary marine
vessel maneuvering support starting button 15 is detected in the
moorage support mode, the stationary marine vessel maneuvering
support controlling section 27 switches the control mode of the
marine vessel running controlling apparatus 20 to the stationary
marine vessel maneuvering support mode from the moorage support
mode.
[0120] An intermittent shift command signal is also applied to the
shift controlling section 22 from the throttle controlling section
21. Based on the intermittent shift command signal, the shift
controlling section 22 performs an intermittent shift operation to
shift the dog clutches 43d alternately between the neutral position
and the forward drive position or between the neutral position and
the reverse drive position when the engine speeds for the target
propulsive forces are lower than an idle speed of the engines 39 (a
lower limit engine speed, for example, about 700 rpm). The
intermittent shift operation makes it possible to generate
propulsive forces for engine speeds lower than the idle speed. The
intermittent shift operation will be described in detail below.
[0121] FIG. 6 is a diagram for explaining an operation for moving
the marine vessel 1 with the orientation of the stem 4 of the
marine vessel 1 being kept unchanged (i.e., with an angular speed
.omega. of 0). A point at which the center line 5 of the hull 2
intersects the stern 3 is defined as an origin O. An axis extending
along the center line 5 toward the stem 4 is defined as an x-axis,
and an axis extending along the stern 3 (transom) toward the port
side is defined as a y-axis. The origin O is a midpoint between
propulsive force generating points at which the propulsive forces
are generated by the respective propulsion units 30 provided in the
outboard motors 11, 12.
[0122] In the stationary marine vessel maneuvering support mode and
the moorage support mode, the steering controlling section 23 sets
the target steering angles .phi.L.sub.t, .phi.R.sub.t of the
port-side and starboard-side outboard motors 11, 12 such that
action lines (indicated by broken lines) extending along vectors
TL, TR of the propulsive forces generated by the respective
outboard motors 11, 12 intersect each other in a predetermined
range on the x-axis and the target angular speed .omega..sub.t (=0)
is attained. At this time, the trim angle controlling section 24
controls the port-side and starboard-side outboard motors 11, 12
such that the trim angles of the respective outboard motors 11, 12
are substantially equal to each other so that horizontal components
of the propulsive forces generated by the propulsion units 30 of
the respective outboard motors 11, 12 are substantially equal to
each other.
[0123] It is assumed that the intersection of the action lines of
the propulsive force vectors TL, TR is defined as an action point
F=(a,0) (wherein a>0), and the port-side and starboard-side
outboard motors 11, 12 respectively generate the propulsive forces
at positions (0,b), (0,-b) (wherein b is a constant value b>0)
that are symmetrical with respect to the center line 5. If the
steering angle .phi.R of the starboard-side outboard motor 12 is
.phi.R=.phi., the steering angle .phi.L of the port-side outboard
motor 11 is expressed by .phi.L=-.phi.. Here, the angle .phi. is
expressed by .phi.=tan.sup.-1(b/a).
[0124] A combined vector obtained by combining the propulsive force
vectors TL, TR at the action point F is herein expressed by TG. The
direction of the combined vector TG (which forms a movement angle
.theta. with the x-axis) indicates the direction of the combined
propulsive force (the movement direction of the hull 2), and the
magnitude of the combined vector TG indicates the magnitude of the
combined propulsive force. Therefore, it is necessary to direct the
combined vector TG at the target movement angle .theta..sub.t
applied from the stationary marine vessel maneuvering support
controlling section 27 and to equalize the magnitude |TG| of the
combined vector TG with the magnitude of the target combined
propulsive force applied from the stationary marine vessel
maneuvering support controlling section 27. In other words, target
propulsive force vectors TL.sub.t, TR.sub.t for the port-side and
starboard-side outboard motors 11, 12 are determined so as to
provide the aforementioned combined vector TG.
[0125] Where the action point F coincides with an instantaneous
center G of the hull 2, the angular speed .omega. of the hull 2
(angular speed about the instantaneous center G) is zero, so that
the hull 2 laterally moves parallel with the orientation of the
stem 4 being maintained unchanged.
[0126] More specifically, as shown in FIG. 7, the steering angles
.phi.R, .phi.L are set at .phi.R=.phi., L=-.phi. (wherein
.phi..gtoreq.0) such that the action point F coincides with the
instantaneous center G. At the same time, the port-side outboard
motor 11 and the starboard-side outboard motor 12 generate the
propulsive forces in the reverse drive direction and in the forward
drive direction, respectively, so as to satisfy an expression
|TL|=|TR|. At this time, the hull 2 is moved parallel leftward
perpendicularly to a stem direction (defined along the center line
5) with the orientation of the stem 4 being kept unchanged.
[0127] In this preferred embodiment, the steering angles .phi.L,
.phi.R are controlled such that the angular speed .omega. detected
by the yaw rate sensor 9 is substantially equal to the target
angular speed .omega..sub.t (=0). In this case, if the angular
speed .omega. is .omega.=0, the action point F coincides with the
instantaneous center G with the instantaneous center G being
located on the center line 5. If the angular speed .omega. is
.omega..noteq.0, the action point F does not coincide with the
instantaneous center G even with the instantaneous center G being
located on the center line 5.
[0128] FIG. 8 is a schematic diagram for explaining a specific
operation for controlling the steering angles .phi.L, .phi.R. The
instantaneous center G is not always located on the center line 5.
In the case of the small-scale marine vessel 1, for example, the
instantaneous center G changes when a crew member moves on the hull
2 or when fish are loaded into an under-deck water tank. Therefore,
the position of the instantaneous center G is not limited to
positions on the center line 5.
[0129] However, it is possible to perform a lateral maneuvering
operation to laterally move the marine vessel 1 as desired with the
action point F being located on the center line 5, even if the
instantaneous center G is not located on the center line 5. More
specifically, a line 60 extending through the instantaneous center
G at the target movement angle .theta..sub.t is drawn, and the
action point F is located at an intersection of the line 60 and the
center line 5. Then, the magnitudes of the propulsive force vectors
TL, TR for the port-side and starboard-side outboard motors 11, 12
are determined so as to provide a combined propulsive force vector
TG extending from the action point F along the line 60. Thus, the
hull 2 can be moved parallel with the angular speed .omega. being
kept at .omega.=0.
[0130] The propulsion units 30 of the port-side and starboard-side
outboard motors 11, 12 are preferably pivotal only in a
mechanically limited angular range about the steering shaft 35.
Therefore, it is impossible, in reality, to locate the action point
F within a range between the origin O and a predetermined lower
limit point (a.sub.min, 0) on the center line 5. Furthermore, if
the action point F is located at a position that is more distant
from the origin O than a predetermined upper limit point
(a.sub.max, 0) on the center line 5 to provide a desired combined
vector TG extending laterally of the hull 2, greatly increased
propulsive forces must be generated from the port-side and
starboard-side outboard motors 11, 12. Therefore, the position of
the action point F on the center line 5 is restricted within a
range .DELTA.x between the points (a.sub.min, 0) and (a.sub.max, 0)
due to limitations in the steering angles of the propulsion units
30 and limitations in the output capabilities of the engines
39.
[0131] Where the instantaneous center G is located at a position
(a', c) in FIG. 8, for example, the aforementioned limitations make
it impossible to move the hull 2 parallel from the instantaneous
center G into the cross-hatched ranges shown in FIG. 8 with the
action point F being located on the center line 5. That is, it is
impossible to set the angular speed .omega. at .omega.=0, thereby
imparting the hull 2 with a rotation moment.
[0132] That is, as shown in FIG. 9, there is a possibility that the
angular speed .omega. cannot be set at .omega.=.omega..sub.t (=0)
even if the steering angle .phi.R is reduced to a predetermined
switching reference steering angle .phi..sub.S. When the steering
angle .phi.R is reduced to the switching reference steering angle
.phi..sub.S, the action point F reaches the point (a.sub.max, 0) on
the center line 5. In this case, the action point F is offset from
the center line 5 in this preferred embodiment. Conversely, if the
steering angles .phi.L, .phi.R are controlled to set the angular
speed .omega. at .omega.=0, the action point F is located on a line
62 extending through the instantaneous center G at the target
movement angle .theta.. Then, the outputs (propulsive forces) of
the port-side and starboard-side outboard motors 11, 12 are
controlled to provide a combined vector TG having a desired
magnitude and a desired direction.
[0133] In general, the instantaneous center G is located within the
hull 2. Therefore, it is necessary to locate the action point F
within a predetermined range .DELTA.y having a width that is
roughly equivalent to the width of the hull 2. When it is
impossible to obtain the target angular speed .omega..sub.t even
with the action point F being located within the predetermined
range .DELTA.y, an alarm may be provided to notify the operator of
this situation.
[0134] Similarly, when it is impossible to attain the target
angular speed .omega..sub.t even with the action point F being
located at the point (a.sub.min, 0) on the center line 5 by
increasing the steering angle .phi.R, an alarm is preferably
provided to notify the operator of this situation.
[0135] In the case shown in FIG. 9, the steering angles .phi.L,
.phi.R of the port-side and starboard-side outboard motors 11, 12
are calculated from the following expressions so as to simplify the
control operation. .phi.L=.psi.-.phi..sub.S
.phi.R=.psi.+.phi..sub.S wherein .psi. is a steering angle
correction value.
[0136] Therefore, the steering angles .phi.L, .phi.R are determined
by properly determining the steering angle correction value .psi.
to attain the target angular speed .omega..sub.t. Thus, the
computation for the control operation is simplified. Here, the
switching reference steering angle .phi..sub.S is a steering angle
which is observed when the action point F is located at the point
(a.sub.max, 0) on the center line 5, and expressed by
.phi..sub.S=tan.sup.-1(b/a.sub.max).
[0137] Referring to FIG. 6, a method for calculating the magnitudes
|TL|, |TR| of the propulsive forces to be generated from the
port-side and starboard-side outboard motors 11, 12 will be
described in more detail.
[0138] It is herein assumed that the magnitude |TR.sub.t| of the
target propulsive force vector TR.sub.t for the starboard-side
outboard motor 12 for providing the target combined propulsive
force magnitude |TG.sub.t| is calculated from the following
expression (1) by multiplying the magnitude |TL.sub.t| of the
target propulsive force vector TL.sub.t for the port-side outboard
motor 11 by a scalar k. |TL.sub.t|=k|TR.sub.t| (1)
[0139] It is further assumed that the target steering angles
.phi.R.sub.t, .phi.L.sub.t of the port-side and starboard-side
outboard motors 11, 12 are determined so as to satisfy an
expression .phi..sub.t=.phi.R.sub.t=-.phi.L.sub.t (wherein
.phi..sub.t is a target steering angle basic value) in the
stationary marine vessel maneuvering support mode and the moorage
support mode.
[0140] Where the target combined propulsive force vector TG.sub.t
is provided by combining the target propulsive force vectors
TL.sub.t, TR.sub.t for the port-side and starboard-side outboard
motors 11, 12, x-axis and y-axis components TG.sub.tx, TG.sub.ty of
the target combined propulsive force vector TG.sub.t satisfy the
following expressions (2) and (3): TG.sub.tx=|TG.sub.t| cos
.theta..sub.t=|TR.sub.t| cos .phi..sub.t+|TL.sub.t| cos .phi..sub.t
(2) TG.sub.ty=|TG.sub.t| sin .theta..sub.t=|TR.sub.t| sin
.phi..sub.t-|TL.sub.t| sin .phi..sub.t (3)
[0141] Then, the magnitude |TR.sub.t| of the target propulsive
force vector TR.sub.t for the starboard-side outboard motor 12 is
expressed by the following expression (4): TR t = TG t .times. (
cos .times. .times. .theta. t + sin .times. .times. .theta. t ) { (
1 + k ) .times. cos .times. .times. .PHI. t + ( 1 - k ) .times. sin
.times. .times. .PHI. t } ( 4 ) ##EQU1##
[0142] On the other hand, the following expression (5) is obtained
from the expressions (2) and (3). tan .times. .times. .theta. t = T
R - T L T R + T L sin .times. .times. .PHI. t cos .times. .times.
.PHI. t = T R - T L T R + T L tan .times. .times. .PHI. t ( 5 )
##EQU2##
[0143] The expression (1) is substituted in the expression (5) to
provide the following expression (6). tan .times. .times. .theta. t
= 1 - k 1 + k tan .times. .times. .PHI. t ( 6 ) ##EQU3##
[0144] By solving this equation, the factor k is expressed by the
following expression (7): k = tan .times. .times. .PHI. t - tan
.times. .times. .theta. t tan .times. .times. .PHI. t + tan .times.
.times. .theta. t ( 7 ) ##EQU4##
[0145] Therefore, the factor k is calculated from the expression
(7) based on the target steering angle basic value .phi..sub.t
(=.phi.R.sub.t) and the target movement angle .theta..sub.t. The
target propulsive force |TR.sub.t| for the starboard-side outboard
motor 12 is calculated from the expression (4) based on the factor
k, the target steering angle basic value .phi..sub.t, the target
movement angle .theta..sub.t and the target combined propulsive
force |TG.sub.t|. Further, the target propulsive force |TL.sub.t|
for the port-side outboard motor 11 is calculated from the
expression (1).
[0146] Therefore, the target propulsive forces |TL.sub.t|,
|TR.sub.t| for the port-side and starboard-side outboard motors 11,
12 are determined based on the input of the target steering angle
basic value .phi..sub.t (which may be a value detected by the
steering angle sensor 49 of the starboard-side outboard motor 12),
the target movement angle .theta..sub.t and the target combined
propulsive force |TG.sub.t| through a computation process performed
by the microcomputer.
[0147] However, when the target movement angle .theta..sub.t is
.theta..sub.t=-.pi./4 or 3.pi./4 (rad), it is impossible to
calculate the target propulsive force |TR.sub.t| from the
expression (4) with the right side of the expression (4) being 0/0.
Therefore, the target propulsive forces |TL.sub.t|, |TR.sub.t| for
different target movement angles .theta..sub.t from 0 to 2.pi. in
increments of .pi./36 are preliminarily calculated based on
different target steering angle basic values .phi..sub.t and
different target combined propulsive forces |TG.sub.t|, and the
results of the calculation are stored in the form of a map, which
is used for the control of the propulsive forces.
[0148] If the action point F is offset from the center line 5 as
shown in FIG. 9, the relationship .phi.L=-.phi.R=-.phi. is not
satisfied. Even in this case, the aforementioned map is useful.
This is because the target steering angles .phi.L.sub.t,
.phi.R.sub.t are determined from the expression
.phi.L.sub.t=.psi..sub.t-.phi..sub.S and
.phi.R.sub.t=.psi..sub.t+.phi..sub.S. More specifically, the target
steering angle basic value .phi..sub.t and the target movement
angle .theta..sub.t are replaced with a target steering angle input
value .phi.R.sub.t-.psi..sub.t (or
.phi..sub.t.rarw..phi.R-.psi..sub.t) and a target movement angle
input value .theta..sub.t-.psi..sub.t, respectively, when the map
is used.
[0149] FIG. 10 is a block diagram illustrating the functions of the
stationary marine vessel maneuvering support controlling section
27. The stationary marine vessel maneuvering support controlling
section 27 includes a stationary marine vessel maneuvering support
start detecting section 161 which detects the operation of the
stationary marine vessel maneuvering support starting button 15, a
coordinate converting section 162 which converts absolute
coordinates (X, Y) of a position of the marine vessel 1 output from
the GPS 10 into relative coordinates (x, y) defined based on the
x-axis and the y-axis on the marine vessel 1, and a marine vessel
maneuvering support starting position storing section 163 which
stores coordinates (x.sub.0, y.sub.0) of a stationary marine vessel
maneuvering support starting position generated by the coordinate
converting section 162 when the operation of the stationary marine
vessel maneuvering support starting button 15 is detected by the
stationary marine vessel maneuvering support start detecting
section 161.
[0150] The relative coordinates (x, y) are based on the origin O
defined by the intersection of the x-axis and the y-axis at a
predetermined time point, for example, when the operation of the
stationary marine vessel maneuvering support starting button 15 is
detected, and the origin O is fixed during the control in the
stationary marine vessel maneuvering support mode.
[0151] The stationary marine vessel maneuvering support controlling
section 27 further includes a target control value calculating
section 164 which determines the magnitude |TG.sub.t| of the target
combined propulsive force and the target movement angle
.theta..sub.t to generate target control values. The target control
value calculating section 164 receives the coordinates (x.sub.0,
y.sub.0) of the stationary marine vessel maneuvering support
starting position applied from the marine vessel maneuvering
support starting position storing section 163 and coordinates (x,
y) of a current position of the marine vessel 1 applied from the
coordinate converting section 162.
[0152] The stationary marine vessel maneuvering support controlling
section 27 further includes a proximity state detecting section 165
which detects the proximity state of the marine vessel 1 based on
the output signals of the respective proximity sensors 18. The
proximity state detecting section 165 generates proximity
information indicating the proximity state, and applies the
proximity information to the target control value calculating
section 164.
[0153] The stationary marine vessel maneuvering support controlling
section 27 further includes a moorage support start detecting
section 166 which detects the operation of the moorage support
starting button 17. A detection signal from the moorage support
start detecting section 166 is applied to the target control value
calculating section 164. A detection signal from the stationary
marine vessel maneuvering support start detecting section 161 is
also applied to the target control value calculating section 164.
The output of the cross button 16 is also applied to the target
control value calculating section 164.
[0154] When the stationary marine vessel maneuvering support
starting button 15 is pressed to switch the control mode to the
stationary marine vessel maneuvering support mode, the target
control value calculating section 164 determines the target
combined propulsive force |TG.sub.t| and the target movement angle
.theta..sub.t based on the coordinates (x.sub.0, y.sub.0) of the
stationary marine vessel maneuvering support starting position, the
coordinates (x, y) of the current marine vessel position and the
output of the cross button 16. On the other hand, when the moorage
support starting button 17 is pressed to switch the control mode to
the moorage support mode, the target control value calculating
section 164 calculates the target combined propulsive force
|TG.sub.t| and the target movement angle .theta..sub.t such that
the marine vessel 1 is maintained in the proximity state according
to the proximity information applied from the proximity state
detecting section 165.
[0155] FIG. 11 is a flowchart of an operation to be performed by
the stationary marine vessel maneuvering support controlling
section 27 in the stationary marine vessel maneuvering support
mode. When the stationary marine vessel maneuvering support
starting button 15 is operated, the stationary marine vessel
maneuvering support controlling operation is started in the
stationary marine vessel maneuvering support mode. In the
stationary marine vessel maneuvering support mode, the coordinate
converting section 162 converts absolute coordinates of a current
marine vessel position output from the GPS 10 into relative
coordinates, which are in turn stored as the coordinates (x.sub.0,
y.sub.0) of the stationary marine vessel maneuvering support
starting position in the marine vessel maneuvering support starting
position storing section 163 (Step S100).
[0156] On the other hand, the target control value calculating
section 164 detects the operation state of the cross button 16
(Step S102).
[0157] If the operation of the cross button 16 is not detected, the
routine goes to Step S104 at a branch in Step S102. That is, a
deviation .DELTA.x (=x-x.sub.0) of a current position x-coordinate
x (relative position coordinate) from a reference x-coordinate
x.sub.0 with respect to the x-axis (hereinafter referred to as
"x-axis deviation .DELTA.x") and a deviation .DELTA.y (=y-y.sub.0)
of a current position y-coordinate y (relative position coordinate)
from a reference y-coordinate y.sub.0 with respect to the y-axis
(hereinafter referred to as "y-axis deviation .DELTA.y") are
determined.
[0158] Then, the magnitudes |TG.sub.tx|, |TG.sub.ty| of the x-axis
and y-axis components of the target combined propulsive force
TG.sub.t are calculated from the following expressions (8), (9),
respectively (Step S106). |TG.sub.tx|=k.sub.x|.DELTA.x| (8)
|TG.sub.ty|=k.sub.y|.DELTA.y| (9) wherein k.sub.x and k.sub.y are
proportionality constants greater than zero (k.sub.x>0,
k.sub.y>0).
[0159] That is, the magnitude |TG.sub.tx| of the x-axis component
is directly proportional to the magnitude |.DELTA.x| of the x-axis
deviation, and the magnitude |TG.sub.ty| of the y-axis component is
directly proportional to the magnitude |.DELTA.y| of the y-axis
deviation.
[0160] Based on the magnitudes |TG.sub.tx|, |TG.sub.ty| of the
x-axis and y-axis components, the target combined propulsive force
|TG.sub.t| is calculated as the magnitude of a vector obtained by
combining the x-axis and y-axis component vectors TG.sub.tx,
TG.sub.ty from the following expression (10) (Step S116). The
directions of the x-axis and y-axis component vectors TG.sub.tx,
TG.sub.ty are determined by signs of the x-axis and y-axis
deviations .DELTA.x, .DELTA.y, respectively.
|TG.sub.t|=|TG.sub.tx+TG.sub.ty| (10)
[0161] Further, the target movement direction .theta..sub.t is
calculated based on a ratio between the x-axis component of the
x-axis component vector TG.sub.tx and the y-axis component of the
y-axis component vector TG.sub.ty from the following expression
(11) (Step S116). .theta..sub.t=tan.sup.-1(TG.sub.tx/TG.sub.ty)
(11)
[0162] The target movement direction .theta..sub.t is such that the
x-axis deviation .DELTA.x and the y-axis deviation .DELTA.y are
eliminated to move the marine vessel 1 back to the stationary
marine vessel maneuvering support starting position (x.sub.0,
y.sub.0).
[0163] Thereafter, it is determined whether the stationary marine
vessel maneuvering support controlling operation is to be
terminated (Step S118). This judgment is positive if the operation
of any of the steering wheel 7a, the throttle levers 8a, 8b and the
moorage support starting button 17 is detected, and is negative if
the operation of any of the steering wheel 7a, the throttle levers
8a, 8b and the moorage support starting button 17 is not
detected.
[0164] When the leftward movement button 16C or the rightward
movement button 16D is operated to move the marine vessel 1 along
the y-axis, the routine goes to Step S108 at the branch in Step
S102. That is, the x-axis deviation .DELTA.x is determined (Step
S108).
[0165] Then, the magnitudes |TG.sub.tx|, |TG.sub.ty| of the x-axis
component and the y-axis component of the target combined
propulsive force TG.sub.t are calculated from the following
expressions (12), (13) (Step S110). |TG.sub.tx|=k.sub.x|.DELTA.x|
(12) |TG.sub.ty|=C.sub.y (13)
[0166] That is, the magnitude |TG.sub.tx| of the x-axis component
is directly proportional to the magnitude |.DELTA.x| of the x-axis
deviation with a proportionality constant k.sub.x, and the
magnitude |TG.sub.ty| of the y-axis component has a very small
constant value C.sub.y (>0).
[0167] The reference y-coordinate y.sub.0 is updated to the
y-coordinate y of the current position (Step S110). This prevents
the marine vessel 1 from being moved back to the stationary marine
vessel maneuvering support starting position when the routine goes
to Step S104 from Step S102 with the operation of the leftward
movement button 16C or the rightward movement button 16D
cancelled.
[0168] Thereafter, a process sequence beginning from Step S116 is
performed. In this case, the sign of the x-axis component vector
TG.sub.tx is determined by the sign of the x-axis deviation
.DELTA.x. Further, the y-axis component vector TG.sub.ty has a plus
sign if the leftward movement button 16D is operated, and has a
minus sign if the rightward movement button 16C is operated.
[0169] Thus, the target movement direction .theta..sub.t indicating
the direction of the target combined propulsive force vector
TG.sub.t is determined to eliminate the x-axis deviation .DELTA.x
and move the marine vessel 1 along the y-axis.
[0170] When the forward movement button 16A or the reverse movement
button 16B is operated to move the marine vessel 1 along the
x-axis, the routine goes to Step S112 at the branch in Step S112.
That is, the y-axis deviation .DELTA.y is determined. Then, the
magnitudes |TG.sub.tx|, |TG.sub.ty| of the x-axis component and the
y-axis component of the target combined propulsive force TG.sub.t
are calculated from the following expressions (14), (15) (Step
S114). |TG.sub.tx|=C.sub.x (14) |TG.sub.ty|=k.sub.y|.DELTA.y|
(15)
[0171] That is, the magnitude |TG.sub.tx| of the x-axis component
has a very small constant value C.sub.x (>0), and the magnitude
|TG.sub.ty| of the y-axis component is directly proportional to the
magnitude |.DELTA.y| of the y-axis deviation with a proportionality
constant k.sub.y.
[0172] The reference x-coordinate x.sub.0 is updated to the
x-coordinate x of the current position (Step S114) This prevents
the marine vessel 1 from being moved back to the stationary marine
vessel maneuvering support starting position when the routine goes
to Step S104 from Step S102 with the operation of the forward
movement button 16A or the reverse movement button 16B is
cancelled.
[0173] Thereafter, a process sequence beginning from Step S116 is
performed. In this case, the sign of the y-axis component vector
TG.sub.ty is determined by the sign of the y-axis deviation
.DELTA.y. Further, the x-axis component vector TG.sub.tx has a plus
sign if the forward movement button 16A is operated, and has a
minus sign if the reverse movement button 16B is operated.
[0174] Thus, the target movement direction .theta..sub.t indicating
the direction of the target combined propulsive force vector
TG.sub.t is determined to eliminate the y-axis deviation .DELTA.y
and move the marine vessel 1 along the x-axis.
[0175] In this manner, the fixed position marine vessel maintaining
operation is performed to maintain the marine vessel 1 at the
stationary marine vessel maneuvering support starting position
despite disturbances being applied to the marine vessel, if none of
the buttons 16A to 16D of the cross button 16 is operated in the
stationary marine vessel maneuvering support mode. When the forward
movement button 16A or the reverse movement button 16B is operated,
the marine vessel 1 is moved along the x-axis with movement of the
marine vessel 1 along the y-axis due to disturbances being
prevented. When the leftward movement button 16C or the rightward
movement button 16D is operated, the marine vessel 1 is moved along
the y-axis with movement of the marine vessel 1 along the x-axis
due to disturbances being prevented. Since the angular speed
.omega. of the marine vessel 1 is maintained at zero in this mode,
the orientation of the stem 4 of the marine vessel 1 is kept
unchanged without turning of the stem 4.
[0176] Therefore, the operator first operates the steering wheel 7a
and the throttle levers 8a, 8b to move the marine vessel 1 into the
vicinity of a desired stop position with the stem 4 of the marine
vessel 1 oriented in a desired direction (e.g., with the center
line 5 of the marine vessel 1 maintained parallel to the pier), and
then operates the stationary marine vessel maneuvering support
starting button 15. Thereafter, the operator operates the cross
button 16 to move the marine vessel 1 forward, reverse, leftward or
rightward with the orientation of the stem 4 of the marine vessel 1
kept unchanged, and then stops the marine vessel 1 at the desired
stop position.
[0177] The stationary marine vessel maneuvering support mode is
also useful for moving the marine vessel 1 away from the pier or
other objects. In this case, the operator operates the cross button
16 to move the marine vessel 1 away from the pier or other objects
with the orientation of the stem 4 of the marine vessel being kept
unchanged.
[0178] FIG. 12 is a flow chart of an operation (proximity state
maintaining controlling operation) to be performed by the
stationary marine vessel maneuvering support controlling section 27
(serving as a proximity state maintaining controlling section in
this case) in the moorage support mode. When the operation of the
moorage support starting button 17 is detected, the target control
value calculating section 164 acquires the proximity information
from the proximity state detecting section 165 (Step S400). Then,
the target control value calculating section 164 determines the
target combined propulsive force vector TG.sub.t so as to maintain
the marine vessel 1 in the proximity state as indicated by the
proximity information. That is, the magnitude |TG.sub.t| of the
target combined propulsive force vector TG.sub.t is set at a very
small constant value C (proximity maintaining target propulsive
force), and the target movement direction .theta..sub.t defining
the direction of the target combined propulsive force vector
TG.sub.t is determined such that the marine vessel 1 is moved
toward an anchoring position (along a line extending from the
center of the marine vessel 1 to the anchoring position) (Step
S402).
[0179] Thus, the port-side and starboard-side outboard motors 11,
12 generate propulsive forces to maintain the marine vessel 1 in
the proximity state, whereby the moorage support controlling
operation is performed to move and press the marine vessel 1 toward
the pier and the other object with a minute force. At this time,
the steering angles of the respective outboard motors 11, 12 are
controlled by the steering controlling section 23 to maintain the
angular speed of the marine vessel 1 at zero.
[0180] In Step S404, it is determined whether the moorage support
controlling operation is to be terminated. This judgment is
positive if the operation of any of the steering wheel 7a, the
throttle levers 8a, 8b and the stationary marine vessel maneuvering
support starting button 15 is detected, and is negative if the
operation of any of the steering wheel 7a, the throttle levers 8a,
8b and the stationary marine vessel maneuvering support starting
button 15 is not detected.
[0181] When the marine vessel 1 is to be brought into contact with
the object (the pier or another marine vessel), the operator
performs an ordinary marine vessel maneuvering operation with the
use of the steering wheel 7a and the like to move the marine vessel
1 sufficiently close to the object with the stem 4 of the marine
vessel 1 oriented in a desired direction, and then operates the
stationary marine vessel maneuvering support starting button 15. In
this state, the operator operates the cross button 16 to move the
marine vessel 1 parallel in the forward, reverse, leftward or
rightward direction toward the object. After the marine vessel 1 is
brought into contact with the object, the operator operates the
moorage support starting button 17. Thus, the marine vessel 1 is
continuously pressed toward the object. Then, the marine vessel 1
is moored to the object with a rope as required.
[0182] On the other hand, when the marine vessel 1 is to be moved
away from the object (the pier or another marine vessel), the
operator first operates the moorage support starting button 17.
Thus, the marine vessel 1 is pressed toward the object, so that the
marine vessel 1 can safely be unmoored from the object. After
operating the stationary marine vessel maneuvering support starting
button 15, the operator operates the cross button 16 to move the
marine vessel 1 away from the object with the orientation of the
stem 4 of the marine vessel 1 kept unchanged. After the marine
vessel 1 is moved sufficiently away from the object, the operator
performs the ordinary marine vessel maneuvering operation with the
use of the steering wheel 7a and the throttle levers 8a, 8b to move
the marine vessel 1.
[0183] The control mode may automatically be switched from the
stationary marine vessel maneuvering support mode to the moorage
support mode. That is, the stationary marine vessel maneuvering
support controlling section 27 may automatically switch the control
mode to the moorage support mode in response to the proximity
sensors 18 detecting the object in contact with the marine vessel 1
(or in close proximity to the marine vessel 1) without the
operation of the moorage support starting button 17 in the
stationary marine vessel maneuvering support mode.
[0184] FIG. 13 is a block diagram illustrating the functions of the
throttle controlling section 21 and the shift controlling section
22, particularly, for explaining the control operations to be
performed by the throttle controlling section 21 and the shift
controlling section 22 in the stationary marine vessel maneuvering
support mode and the moorage support mode. The throttle controlling
section 21 includes a target engine speed calculating module 70
(individual target propulsive force calculating section) which
calculates target engine speeds |NL.sub.t|, |NR.sub.t| of the
engines 39 of the port-side and starboard-side outboard motors 11,
12, and a throttle opening degree calculating module 80 (propulsive
force controlling section) which calculates the target throttle
opening degrees of the engines 39 of the outboard motors 11, 12
based on the calculated target engine speeds |NL.sub.t|,
|NR.sub.t|.
[0185] The target engine speed calculating module 70 includes a
steering angle input value calculating section 71 which receives
the steering angle .phi.R (or the target steering angle
.phi.R.sub.t) of the starboard-side outboard motor 12 and the
target steering angle correction value .psi..sub.t from the
steering controlling section 23 and calculates the steering angle
input value .phi.R-.psi..sub.t (or .phi.R.sub.t-.psi..sub.t) to be
used in a map search, and a target movement angle input value
calculating section 72 which calculates the target movement angle
input value .theta..sub.t-.psi..sub.t to be used in the map search
based on the target movement angle .theta..sub.t and the target
steering angle correction value .psi..sub.t from the stationary
marine vessel maneuvering support controlling section 27. The
target engine speed calculating module 70 further includes a target
propulsive force calculating section 74 which calculates the target
propulsive forces |TL.sub.t|, |TR.sub.t| of the port-side and
starboard-side outboard motor 11, 12, a propulsive force-to-engine
speed conversion table 75 which determines the target engine speeds
NL.sub.t, NR.sub.t (with signs indicating the directions of the
propulsive forces to be generated) of the port-side and
starboard-side outboard motors 11, 12 for the target propulsive
forces |TL.sub.t|, |TR.sub.t|, and a lower limit engine speed
judging section 76 which calculates the absolute values |NL.sub.t|,
|NR.sub.t| of the target engine speeds and compares the absolute
values |NL.sub.t|, |NR.sub.t| with the lower limit engine speed
(which is, for example, equal to the idle speed of the engines
39).
[0186] The target propulsive force calculating section 74 is
defined by the aforementioned map which outputs the target
propulsive forces |TL.sub.t|, |TR.sub.t| of the port-side and
starboard-side outboard motors 11, 12 based on the steering angle
input value .phi.R-.psi..sub.t (or .phi.R.sub.t-.psi..sub.t), the
target movement angle input value .theta..sub.t-.psi..sub.t and the
target combined propulsive force |TG.sub.t| applied from the
stationary marine vessel maneuvering support controlling section
27.
[0187] The target propulsive forces |TL.sub.t|, |TR.sub.t| are not
suitable for the control of the engines 39 and, therefore, are
converted into the target engine speeds NL.sub.t, NR.sub.t
according to the characteristics of the engines 39 with reference
to the propulsive force-to-engine speed conversion table 75. The
signs of the target engine speeds NL.sub.t, NR.sub.t are determined
according to the target movement angle .theta..sub.t. More
specifically, if the target movement angle .theta..sub.t is
0.ltoreq..theta..sub.t.ltoreq..pi., a minus sign indicating the
reverse drive direction is assigned to the target engine speed
NL.sub.t of the port-side outboard motor 11, and a plus sign
indicating the forward drive direction is assigned to the target
engine speed NR.sub.t of the starboard-side outboard motor 12. On
the other hand, if the target movement angle .theta..sub.t is
.pi.<.theta..sub.t<2.pi. (or -.pi.<.theta..sub.t<0), a
plus sign indicating the forward drive direction is assigned to the
target engine speed NL.sub.t of the port-side outboard motor 11,
and a minus sign indicating the reverse drive direction is assigned
to the target engine speed NR.sub.t of the starboard-side outboard
motor 12. The target engine speeds NL.sub.t, NR.sub.t thus
determined are input not only to the lower limit engine speed
judging section 76 (rotational speed comparing section), but also
to the shift controlling section 22.
[0188] The lower limit engine speed judging section 76 determines
whether the absolute values |NL.sub.t|, |NR.sub.t| of the target
engine speeds are less than the lower limit engine speed NLL (which
is equal to the idle speed), and applies judgment results to the
shift controlling section 22. Further, the absolute values
|NL.sub.t|, |NR.sub.t| of the target engine speeds are applied to
the throttle opening degree calculating module 80. However, if the
target engine speed |NL.sub.t| of the port-side outboard motor 11
is less than the lower limit engine speed NLL, the lower limit
engine speed judging section 76 substitutes the lower limit engine
speed NLL for the target engine speed |NL.sub.t|. Similarly, if the
target engine speed |NR.sub.t| of the starboard-side outboard motor
12 is less than the lower limit engine speed NLL, the lower limit
engine speed judging section 76 substitutes the lower limit engine
speed NLL for the target engine speed |NR.sub.t|.
[0189] The throttle opening degree calculating module 80 includes a
port-side PI (proportional integration) control module 81 and a
starboard-side PI control module 82, which have substantially the
same construction. The port-side PI control module 81 receives the
target engine speed |NL.sub.t| of the port-side outboard motor 11
input from the lower limit engine speed judging section 76, and a
current engine speed NL (.gtoreq.0) input from the outboard motor
ECU 13 of the port-side outboard motor 11. A deviation
.epsilon.L=|NL.sub.t|-NL of the current engine speed NL from the
target engine speed |NL.sub.t| of the port-side outboard motor 11
is calculated by a deviation computing section 83. The deviation
.epsilon.L is output from the deviation computing section 83 to a
proportional gain multiplying section 84, and to an integrating
section 85 in which the deviation .epsilon.L is subjected to a
discrete integration process. The integration result provided by
the integrating section 85 is applied to an integration gain
multiplying section 86. The proportional gain multiplying section
84 outputs a value obtained by multiplying the deviation .epsilon.L
by a proportional gain kp, and the integration gain multiplying
section 86 outputs a value obtained by multiplying the integration
value of the deviation .epsilon.L by an integration gain ki. These
values are added by the adding section 87 to provide a target
throttle opening degree of the engine 39 of the port-side outboard
motor 11. The target throttle opening degree is applied to the
outboard motor ECU 13 of the port-side outboard motor 11. The
port-side PI control module 81 thus performs a so-called PI
(proportional integration) control.
[0190] The starboard-side PI control module 82 preferably has
substantially the same construction as the port-side PI control
module 81. That is, the starboard-side PI control module 82
processes a deviation .epsilon.R of a current engine speed NR
(.gtoreq.0) from the target engine speed |NR.sub.t| of the
starboard-side outboard motor 12 through the PI (proportional
integration) control, and outputs a target throttle opening degree
of the engine 39 of the starboard-side outboard motor 12. The
target throttle opening degree is applied to the outboard motor ECU
14 of the starboard-side outboard motor 12.
[0191] The shift controlling section 22 includes a port-side shift
control module 91 and a starboard-side shift control module 92,
which have substantially the same construction. Each of the shift
control modules 91, 92 generates a shift controlling signal for
controlling the shift mechanism 43 (more specifically, the dog
clutch 43d) of the outboard motor 11, 12 based on the target engine
speed NL.sub.t, NR.sub.t applied from the propulsive
force-to-engine speed conversion table 75 to switch the shift
position of the shift mechanism 43 to the forward drive position,
the reverse drive position or the neutral position. Each of the
shift control modules 91, 92 performs an intermittent shift control
operation (intermittent coupling control operation) for
periodically switching the shift position of the shift mechanism 43
alternately between the neutral position and the forward drive
position or between the neutral position and the reverse drive
position to intermittently couple the engine 39 to the propeller 40
when the target engine speed NL.sub.t, NR.sub.t is less than the
lower limit engine speed NLL.
[0192] The intermittent shift control operation will hereinafter be
referred to as "PWM control" (pulse width modulation control). In a
shift-in period S.sub.in of a PWM control period S, the rotation of
the engine 39 is transmitted to the propeller shaft 42 with the
shift position being set at the forward drive position or the
reverse drive position. In a neutral period S-S.sub.in of the PWM
control period S, the shift position is set at the neutral
position.
[0193] The port-side shift control module 91 includes a shift rule
table 93 which outputs the shift position (the forward drive
position, the reverse drive position or the neutral position) of
the shift mechanism 43 based on the sign of the target engine speed
NL.sub.t of the port-side outboard motor 11 applied from the
propulsive force-to-engine speed conversion table 75. The port-side
shift control module 91 further includes a shift-in period
calculating section 94 (coupling duration calculating section)
which calculates the shift-in period S.sub.in based on the absolute
value |NL.sub.t| of the target engine speed NL.sub.t applied from
the propulsive force-to-engine speed conversion table 75. The
port-side shift control module 91 further includes a shift position
outputting section 95 (intermittent coupling controlling section)
which generates a shift position signal indicating the shift
position of the shift mechanism 43 of the port-side outboard motor
11 based on the outputs of the shift rule table 93 and the shift-in
period calculating section 94.
[0194] The shift rule table 93 outputs a signal indicating the
forward drive position when the target engine speed NL.sub.t has a
plus sign, and outputs a signal indicating the reverse drive
position when the target engine speed NL.sub.t has a minus sign.
Where the absolute value of the target engine speed NL.sub.t is
determined to be substantially zero (for example, not higher than
about 100 rmp), the shift rule table 93 outputs a signal indicating
the neutral position.
[0195] The shift-in period calculating section 94 sets the shift-in
period S.sub.in at S.sub.in=S if the lower limit engine speed
judging section 76 determines that the target engine speed NL.sub.t
is not less than the lower limit engine speed NLL. In this case,
the PWM control is not performed, but the shift position of the
shift mechanism 43 is maintained at the shift position output from
the shift rule table 93. On the other hand, if the lower limit
engine speed judging section 76 determines that the target engine
speed NL.sub.t is less than the lower limit engine speed NLL, the
shift-in period calculating section 94 sets the shift-in period
S.sub.in at S.sub.in=SD wherein D=NL.sub.t/NLL is a duty ratio for
the PWM control.
[0196] The shift position outputting section 95 outputs the shift
position signal in a cycle of the PWM period S. More specifically,
the shift position outputting section 95 continuously generates the
shift position signal according to the output of the shift rule
table 93 over the shift-in period S.sub.in calculated by the
shift-in period calculating section 94 in the PWM period S, and
generates the shift position signal indicating the neutral position
in the neutral period irrespective of the output of the shift rule
table 93. If the shift-in period S.sub.in is S.sub.in=S, the shift
position signal according to the output of the shift rule table 93
is continuously output.
[0197] The starboard-side shift control module 92 has substantially
the same construction as the port-side shift control module 91, and
controls the shift position of the shift mechanism 43 of the
starboard-side outboard motor 12 by performing the aforementioned
operation based on the target engine speed NR.sub.t of the
starboard-side outboard motor 12 and the judgment result on the
absolute value of the target engine speed NR.sub.t provided by the
lower limit engine speed judging section 76.
[0198] The engines 39 of the outboard motors 11, 12 are each
intrinsically inoperative at an engine speed less than the lower
limit engine speed NLL, such that an output less than the lower
limit engine speed NLL is not provided. In this preferred
embodiment, therefore, if the target engine speeds NL.sub.t,
NR.sub.t are each set to have an absolute value that is less than
the lower limit engine speed NLL, the engines 39 are each operated
at the lower limit engine speed NLL, and the rotation thereof is
intermittently transmitted to the propeller 40 at the duty ratio D
which depends upon the target engine speed NL.sub.t, NR.sub.t.
Thus, the propulsive force can be provided for an engine speed that
is less than the idle speed NLL.
[0199] The shift controlling section 22 further includes an engine
state judging section 90 (motor state judging section) for judging
whether the engines 39 of the port-side and starboard-side outboard
motors 11, 12 are inactive in the stationary marine vessel
maneuvering support mode and the moorage support mode. The engine
state judging section 90 acquires the engine speeds NL, NR of the
engines 39 of the port-side and starboard-side outboard motors 11,
12 from the outboard motor ECUs 13, 14. Then, the engine state
judging section 90 judges whether the engines 39 are active based
on whether or not the engine speeds NL, NR are substantially zero.
If at least one of the engines 39 of the outboard motors 11, 12 is
inactive in the stationary marine vessel maneuvering support mode
or the moorage support mode, a signal indicating the inactive
engine state is applied to the shift position outputting sections
95 of the shift control modules 91, 92. In response to this signal,
each of the shift position outputting sections 95 controls the
shift mechanism 43 of the outboard motor 11, 12 to switch the shift
position of the shift mechanism 43 to the neutral position.
[0200] The engine state judging section 90 also functions as a
restart controlling section for controlling the restart of the
engines 39. That is, when the engine state judging section 90
determines that at least one of the engines 39 of the outboard
motors 11, 12 is inactive in the stationary marine vessel
maneuvering support mode or the moorage support mode, the engine
state judging section 90 provides a command to the outboard motor
ECU 13, 14 of the corresponding outboard motor 11, 12 to restart
the inactive engine 39. In response to the command, the outboard
motor ECU 13, 14 actuates the starter motor 45 of the inactive
engine 39.
[0201] The engine state judging section 90 monitors the engine
speeds NL, NR to determine whether the inactive engine 39 is
restarted. When the engines 39 of the respective outboard motors
11, 12 become active after the restart of the inactive engine 39, a
signal indicating the engine active state is applied to the shift
position outputting sections 95. In response to this signal, the
shift position outputting sections 95 of the shift control modules
91, 92 are each returned to an ordinary state to control the shift
mechanism 43 according to the outputs of the shift rule table 93
and the shift-in period calculating section 94.
[0202] FIG. 14 is a timing chart of the PWM operation to be
performed by the port-side shift control module 91 and the
starboard-side shift control module 92. In FIG. 9, solid lines
indicate a change in the shift position of the shift mechanism 43
of the port-side outboard motor 11 to be controlled by the
port-side shift control module 91, and broken lines indicate a
change in the shift position of the shift mechanism 43 of the
starboard-side outboard motor 12 to be controlled by the
starboard-side shift control module 92.
[0203] Herein, it is assumed that the absolute values of the target
engine speeds NL.sub.t, NR.sub.t of the port-side and
starboard-side outboard motors 11, 12 are less than the lower limit
engine speed (idle speed) NLL. At this time, the shift-in period
calculating sections 94 provided in the port-side shift control
module 91 and the starboard-side shift control module 92
respectively calculate shift-in periods S.sub.in.sub.--L and
S.sub.in.sub.--R. Therefore, the dog clutch 43d of the port-side
outboard motor 11 is located at the forward drive position or the
reverse drive position over the shift-in period S.sub.in.sub.--L in
the PWM period S, and located at the neutral position in a neutral
period S-S.sub.in.sub.--L. Similarly, the dog clutch 43d of the
starboard-side outboard motor 12 is located at the forward drive
position or the reverse drive position over the shift-in period
S.sub.in.sub.--R in the PWM period S, and located at the neutral
position in a neutral period (S-S.sub.in.sub.--R). In the shift-in
periods S.sub.in.sub.--L, S.sub.in.sub.--R, the rotation of each of
the engines 39 rotating at the lower limit engine speed NLL is
transmitted to the corresponding propeller 40.
[0204] In this preferred embodiment, the PWM shift control
operations performed by the shift position outputting sections 95
of the port-side and starboard-side shift control modules 91, 92
are synchronized with each other. That is, as shown in FIG. 14, the
shift-in timings in the PWM shift control operations are
synchronized in each PWM period. Thus, the on-board comfort is
improved in the PWM control. Of course, the required propulsive
forces can be generated from the respective outboard motors 11, 12
without synchronization of the PWM shift control operations.
However, the lag of the shift timings of the port-side and
starboard-side outboard motors 11, 12 results in poorer on-board
comfort.
[0205] FIG. 15 is a block diagram illustrating the function of the
steering controlling section 23, particularly, for explaining a
control operation to be performed by the steering controlling
section 23 in the stationary marine vessel maneuvering support mode
and the moorage support mode. The steering controlling section 23
includes a first target steering angle computing section 101
(target steering angle calculating section) which computes the
target steering angles .phi.R.sub.t, .phi.L.sub.t to be set when
the action point F is located on the center line 5, a second target
steering angle computing section 102 (target steering angle
calculating section) which computes the target steering angle
.phi.R.sub.t, .phi.L.sub.t to be set when the action point F is
located outside the center line 5, a selector 103 which selects
outputs of either of the first target steering angle computing
section 101 and the second target steering angle computing section
102, and a comparing section 104 which controls switching of the
selector 103.
[0206] The comparing section 104 compares the target steering angle
.phi.R.sub.t of the starboard-side outboard motor 12 computed by
the first target steering angle computing section 101 with the
switching reference steering angle .phi..sub.S
(=tan.sup.-1(b/a.sub.max) That is, if the target steering angle
.phi.R.sub.t of the starboard-side outboard motor 12 computed by
the first target steering angle computing section 101 is not less
than the switching reference steering angle .phi..sub.S, the
comparing section 104 controls the selector 103 to select the
outputs of the first target steering angle computing section 101.
On the other hand, if the target steering angle .phi.R.sub.t of the
starboard-side outboard motor 12 computed by the first target
steering angle computing section 101 is less than the switching
reference steering angle .phi..sub.S, the comparing section 104
controls the selector 103 to select the outputs of the second
target steering angle computing section 102.
[0207] The first target steering angle computing section 101 is
defined by a PI (proportional integration) control module based on
the input of the angular speed .omega. detected by the yaw rate
sensor 9 and the target angular speed .omega..sub.t applied from
the stationary marine vessel maneuvering support controlling
section 27. That is, the first target steering angle computing
section 101 is operative such that the angular speed .omega. is
substantially equal to the target angular speed .omega..sub.t (=0)
through PI control. More specifically, the first target steering
angle computing section 101 includes a deviation computing section
106 which computes a deviation .epsilon..sub..omega. of the angular
speed .omega. from the target angular speed .omega..sub.t, a
proportional gain multiplying section 107 which multiplies the
output .epsilon..sub..omega. of the deviation computing section 106
by a proportional gain k.sub..omega.1, an integrating section 108
which integrates the deviation .epsilon..sub..omega. output from
the deviation computing section 106, an integration gain
multiplying section 109 which multiplies the output of the
integrating section 108 by an integration gain k.sub..theta.1, and
a first adding section 110 which generates a steering angle
deviation .DELTA..phi. by adding the output of the proportional
gain multiplying section 107 and the output of the integration gain
multiplying section 109. These components define a steering angle
deviation computing section.
[0208] Further, the first target steering angle computing section
101 includes a memory 111 (basic target steering angle storing
section) which stores an initial target steering angle .phi.i as a
basic target steering angle, and a second adding section 112
(adding section) which determines the target steering angle basic
value .phi..sub.t (=.phi.i+.DELTA..phi.) by adding the steering
angle deviation .phi..sub.f generated by the first adding section
110 to the initial target steering angle .phi.i stored in the
memory 111. The target steering angle basic value .phi..sub.t is
used as the target steering angle .phi.R.sub.t of the
starboard-side outboard motor 12. Further, the sign of the target
steering angle basic value .phi..sub.t is reversed by a reversing
section 113 to provide a value -.phi..sub.t which is used as the
target steering angle .phi.L.sub.t of the port-side outboard motor
11.
[0209] The memory 111 is preferably a nonvolatile rewritable
memory, such as a flash memory or an EEPROM (electrically erasable
programmable read only memory). The initial target steering angle
.phi.i is written in the memory 111, for example, by a special
inputting device prior to delivery of the marine vessel 1 from a
dealer to a user. The initial target steering angle .phi.i is set
at .phi.i=tan.sup.-1(b/a.sub.i) based on a design instantaneous
center Gi (a.sub.i,0) which is determined by the type of the hull 2
and the outboard motors 11, 12. The instantaneous center Gi
(a.sub.i,0) may be experimentally determined by test cruising.
[0210] Parameters a.sub.i and b for the initial target steering
angle .phi..sub.i may be stored as initial target steering angle
information in the memory 111. In this case, the initial target
steering angle .phi.i is calculated from an expression
.phi.i=tan.sup.-1(b/a.sub.i).
[0211] In this preferred embodiment, a learning function is
provided for learning the fluctuation of the instantaneous center G
due to a change in the load on the marine vessel 1 and other
factors. That is, a writing section 114 is provided for updating
the initial target steering angle .phi.i in the memory 111. The
writing section 114 writes the target steering angle basic value
.phi..sub.t generated by the second adding section 112 as a new
initial target steering angle .phi.i in the memory 111 when the
running control is terminated by stopping the driving of the
outboard motors 11, 12 or when the control mode is switched from
the stationary marine vessel maneuvering support mode or the
moorage support mode to the ordinary running mode.
[0212] The second target steering angle computing section 102 is
also defined by a PI (proportional integration) control module
based on the input of the angular speed .omega. detected by the yaw
rate sensor 9 and the target angular speed .omega..sub.t applied
from the stationary marine vessel maneuvering support controlling
section 27. That is, the second target steering angle computing
section 102 is operative such that the angular speed .omega. is
substantially equal to the target angular speed .omega..sub.t
through PI control. More specifically, the second target steering
angle computing section 102 includes a deviation computing section
116 which computes a deviation .epsilon..sub..omega. of the angular
speed .omega. from the target angular speed .omega..sub.t, a
proportional gain multiplying section 117 which multiplies the
output .epsilon..sub..omega. of the deviation computing section 116
by a proportional gain k.sub..omega.2, an integrating section 118
which integrates the deviation .epsilon..sub..omega. output from
the deviation computing section 116, an integration gain
multiplying section 119 which multiplies the output of the
integrating section 118 by an integration gain k.sub..theta.2, and
a first adding section 120 which generates a target steering angle
correction value .psi..sub.t by adding the output of the
proportional gain multiplying section 117 and the output of the
integration gain multiplying section 119. The second target
steering angle computing section 102 further includes a memory 121
which stores the switching reference steering angle .phi..sub.S, a
second adding section 122 which determines the target steering
angle .phi.R.sub.t (=.phi..sub.S+.psi..sub.t) of the starboard-side
outboard motor 12 by adding the switching reference steering angle
.theta..sub.S stored in the memory 121 to the target steering angle
correction value .psi..sub.t generated by the first adding section
120, a reversing section 123 which reverses the sign of the
switching reference steering angle .phi..sub.S to provide an
reversed value -.phi..sub.S, and a third adding section 124 which
provides the target steering angle .phi.L.sub.t
(=-.phi..sub.S+.psi..sub.t) of the port-side outboard motor 11 by
adding the target steering angle correction value .psi..sub.t to
the value -.phi..sub.S provided by the reversing section 123. The
switching reference steering angle .phi..sub.S is also applied to
the comparing section 104 from the memory 121.
[0213] Further, the selector 103 selectively outputs the target
steering angle correction value .psi..sub.t provided by the first
adding section 120 or zero.
[0214] With this arrangement, if it is possible to attain the
target angular speed .omega..sub.t by moving the action point F in
the predetermined range .DELTA..sub.x (x-a.sub.min to a.sub.max,
see FIG. 9) on the center line 5, the selector 103 selects the
target steering angles .phi.L.sub.t, .phi.R.sub.t provided by the
first target steering angle computing section 101, and applies the
target steering angles .phi.L.sub.t, .phi.R.sub.t to the outboard
motor ECUs 13, 14. At this time, the target steering angles
.phi.L.sub.t, .phi.R.sub.t of the port-side and starboard-side
outboard motors 11, 12 satisfy the relationship
.phi.L.sub.t=-.phi.R.sub.t. Further, the selector 103 outputs
.psi..sub.t=0 as the target steering angle correction value
.psi..sub.t to be used for the computation in the throttle
controlling section 21.
[0215] On the other hand, if it is not possible to attain the
target angular speed .omega..sub.t by moving the action point F in
the predetermined range .DELTA.x on the center line 5, the target
steering angle .phi.R.sub.t becomes less than the switching
reference steering angle .phi..sub.S (.phi.R.sub.t<.phi..sub.S)
when the action point Freaches the endpoint (a.sub.max, 0) of the
range .DELTA.x. Therefore, the selector 103 selects the output of
the second target steering angle computing section 102. Thus, the
target steering angles .phi.L.sub.t, .phi.R.sub.t based on the
switching reference steering angle .phi..sub.S are set for the
port-side and starboard-side outboard motors 11, 12, such that the
action point F is located outside the center line 5. Further, the
selector 103 outputs the value provided by the first adding section
120 as the target steering angle correction value .psi..sub.t to be
used for the computation in the throttle controlling section
21.
[0216] FIG. 16 is a flow chart for explaining a throttle
controlling operation to be performed by the throttle controlling
section 21. The target engine speed calculating module 70 acquires
the starboard-side target steering angle .phi.R.sub.t (or the
actually detected steering angle .phi..sub.R) and the target
steering angle correction value .psi..sub.t from the steering
controlling section 23, and acquires the target movement angle
.theta..sub.t and the target combined propulsive force |TG.sub.t|
from the stationary marine vessel maneuvering support controlling
section 27 (Step S10).
[0217] The target propulsive forces |TL.sub.t|, |TR.sub.t| of the
port-side and starboard-side outboard motors 11, 12 are calculated
based on the starboard-side target steering angle .phi.R.sub.t, the
target steering angle correction value .psi..sub.t, the target
movement angle .theta..sub.t and the target combined propulsive
force |TG.sub.t| primarily by the operation of the target
propulsive force calculating section 74 (Step S11). Further, the
target engine speeds NL.sub.t, NR.sub.t are determined according to
the target propulsive forces |TL.sub.t|, |TR.sub.t| and the target
movement angle .theta..sub.t by the propulsive force-to-engine
speed conversion table 75 (if the absolute values of the target
engine speeds NL.sub.t, NR.sub.t are less than the lower limit
engine speed NLL, the target engine speeds NL.sub.t, NR.sub.t are
each set at the lower limit engine speed NLL) (Step S12). Throttle
opening degree commands are generated based on the target engine
speeds NL.sub.t, NR.sub.t primarily by the operation of the
throttle opening degree calculating module 80, and applied to the
outboard motor ECUs 13, 14 (Step S13). According to the applied
throttle opening degree commands, the outboard motor ECUs 13, 14
control the respective throttle actuators 52 (Step S14). In this
manner, the throttle opening degrees of the engines 39 of the
respective outboard motors 11, 12 are controlled, whereby the
engine speeds of the engines 39 are controlled. Thus, the port-side
and starboard-side outboard motors 11, 12 generate the target
propulsive forces |TL.sub.t|, |TR.sub.t|, respectively.
[0218] The throttle controlling section 21 determines whether the
control operation in the stationary marine vessel maneuvering
support mode or the moorage support mode is to be continued (Step
S15). If a significant input from the steering operational section
7 or the throttle operational section 8 is detected, the control
operation from Step S10 to Step S14 is terminated to return the
control mode back to the ordinary running mode from the stationary
marine vessel maneuvering support mode or the moorage support mode.
If the control operation in the stationary marine vessel
maneuvering support mode or the moorage support mode is continued,
the process beginning from Step S10 is repeated.
[0219] FIG. 17 is a flow chart for explaining a control operation
for controlling the shift mechanism 43 of the port-side outboard
motor 11. When the target engine speed NL.sub.t is provided by the
propulsion force-to-engine speed conversion table 75 (Step S20),
the lower limit engine speed judging section 76 compares the
absolute value |NL.sub.t| of the target engine speed NL.sub.t with
the lower limit engine speed NLL (Step S21). If the target engine
speed NL.sub.t is less than the lower limit engine speed NLL, the
shift-in period calculating section 94 of the shift controlling
section 22 sets the duty ratio D at D=NL.sub.t/NLL, and the lower
limit engine speed judging section 76 inputs the target engine
speed NL.sub.t having an absolute value replaced with the value of
the lower limit engine speed NLL to the throttle opening degree
calculating module 80 (the port-side PI control module 81) (Step
S22A).
[0220] The shift-in period calculating section 94 calculates the
shift-in period S.sub.in=SD (Step S23). Further, the shift position
is determined according to the target engine speed NL.sub.t by the
shift rule table 93 (Step S23). Based on the shift-in period
S.sub.in and the shift position, a shift position command is output
from the shift position outputting section 95 (Step S24). The
outboard motor ECU 13 controls the shift actuator 52 based on the
shift position command.
[0221] If the target engine speed NL.sub.t is not less than the
lower limit engine speed NLL (Step S21), the shift-in period
calculating section 94 sets the duty ratio D at D=1, and the lower
limit engine speed judging section 76 inputs the target engine
speed NL.sub.t as is to the throttle opening degree calculating
module 80 (the port-side PI control module 81) (Step S22B).
Thereafter, an operation from Step S23 is performed.
[0222] Judgment in Step S25 is performed in the same manner as in
Step S15 of FIG. 16 by the throttle controlling section 21.
[0223] A control operation for the shift mechanism 43 of the
starboard-side outboard motor 12 is performed in substantially the
same manner.
[0224] FIG. 18 is a flow chart for explaining a control operation
to be performed by the steering controlling section 23 in the
stationary marine vessel maneuvering support mode and the moorage
support mode. The steering controlling section 23 acquires the
angular speed .omega. detected by the yaw rate sensor 9 and the
target angular speed .omega..sub.t (=0) input from the stationary
marine vessel maneuvering support controlling section 27 (Step
S30A). The first target steering angle computing section 101
determines the target steering angle basic value
.phi..sub.t=.phi.i+.DELTA..phi. through the PI control (Step S30B).
Then, the target steering angles .phi.L.sub.t=-.phi.t,
.phi.R.sub.t=.phi..sub.t of the port-side and starboard-side
outboard motors 11, 12 are determined and input to the selector 103
(Step S31).
[0225] On the other hand, the comparing section 104 compares the
target steering angle basic value .phi..sub.t with the switching
reference steering angle .phi..sub.s (=tan.sup.-1(b/a.sub.max))
(Step S32). If .phi..sub.t.gtoreq..phi..sub.S, the selector 103 is
controlled to select the output of the first target steering angle
computing section 101 (Step S33). Then, the steering controlling
section 23 resets the integration value of the integrating section
118 of the second target steering angle computing section 102 to
zero (Step S34). If .phi..sub.t<.phi..sub.S, the selector 103 is
controlled to select the output of the second target steering angle
computing section 102 (Step S35). The second target steering angle
computing section 102 calculates the target steering angle
correction value .psi..sub.t through the PI control (Step S36).
Based on the target steering angle correction value .psi..sub.t,
the target steering angles .phi.L.sub.t=.psi..sub.t-.phi..sub.S,
.phi.R.sub.t=.psi..sub.t+.phi..sub.S of the port-side and
starboard-side outboard motors 11, 12 are calculated (Step
S37).
[0226] The target steering angles .phi.L.sub.t, .phi.R.sub.t of the
port-side and starboard-side outboard motors 11, 12 selected by the
selector 103 are output to the outboard motor ECUs 13, 14 (Step
S38). Then, the outboard motor ECUs 13, 14 respectively control the
steering actuators 53 of the port-side and starboard-side outboard
motors 11, 12 based on the applied target steering angles
.phi.L.sub.t, .phi.R.sub.t. Thereafter, the steering controlling
section 23 determines whether the control operation in the
stationary marine vessel maneuvering support mode or the moorage
support mode is to be terminated (Step S39). The judgment is
performed in the same manner as in Step S15 of FIG. 16 by the
throttle controlling section 21. If the control operation in the
stationary marine vessel maneuvering support mode or the moorage
support mode is continued, the process beginning from Step S30A is
repeated.
[0227] FIG. 19 is a flow chart for explaining an engine stop
checking process to be performed in the stationary marine vessel
maneuvering support mode and the moorage support mode by the engine
state judging section 90 of the shift controlling section 22 for
checking the engine stop of the outboard motors 11, 12. The engine
state judging section 90 monitors the engine speeds NL, NR applied
from the outboard motor ECUs 13, 14 to determine whether or not the
engines 39 of the outboard motors 11, 12 are inactive (Step S40).
If the engines 39 of the outboard motors 11, 12 are both active,
the shift position outputting sections 95 continuously control the
respective shift mechanisms 43 (Step S41).
[0228] On the other hand, if the inactive state of at least one of
the engines 39 of the outboard motors 11, 12 is detected, a command
for setting the shift position of each of the shift mechanisms 43
of the outboard motors 11, 12 at the neutral position is applied to
the shift position outputting sections 95 (Step S42). Thus, neither
of the outboard motors 11, 12 generate the propulsive forces. Then,
a restart command for restarting the inactive engine 39 is applied
to the corresponding one of the outboard motor ECUs 13, 14 of the
outboard motors 11, 12 from the engine state judging section 90
(Step S43). Thus, the inactive engine 39 is restarted by the
starter motor 45 of the corresponding outboard motor 11, 12.
[0229] Thereafter, the engine state judging section 90 determines
whether the control operation is to be terminated (Step S44). The
judgment is preferably performed in the same manner as in Step S15
of FIG. 16 by the throttle controlling section 21. If the control
operation in the stationary marine vessel maneuvering support mode
or the moorage support mode is continued, the process beginning
from Step S40 is repeated.
[0230] FIG. 20 is a block diagram illustrating a second preferred
embodiment of the present invention, and particularly illustrating
the construction of an engine speed calculating module 130 to be
provided instead of the target engine speed calculating module 70
shown in FIG. 13. In FIG. 20, functional components corresponding
to those shown in FIG. 13 are denoted by the same reference
characters as in FIG. 13. Further, reference will be made again to
FIGS. 1 to 19.
[0231] In this preferred embodiment, the target engine speed
NL.sub.t of the port-side outboard motor 11 is determined according
to the target combined propulsive force |TG.sub.t| applied from the
stationary marine vessel maneuvering support controlling section 27
by a propulsive force-to-engine speed conversion table 131 (first
rotational speed setting section). The target engine speed NL.sub.t
is applied to an engine speed computing section 132 (second
rotational speed setting section). Further, the target steering
angle .phi.R.sub.t (or the detected steering angle .phi.R) of the
starboard-side outboard motor 12, the target steering angle
correction value .psi..sub.t and the target movement angle
.theta..sub.t are applied to an engine speed computing section 132.
Based on the target engine speed NL.sub.t, the target steering
angle .phi.R.sub.t, the target steering angle correction value
.psi..sub.t and the target movement angle .theta..sub.t, the engine
speed computing section 132 determines the target engine speed
NR.sub.t for the engine 39 of the starboard-side outboard motor 12
so as to provide the combined propulsive force for moving the hull
2 at the target movement angle .theta..sub.t.
[0232] The target engine speed NL.sub.t is not necessarily equal to
an engine speed required to generate a propulsive force from the
outboard motor 11 for providing the target combined propulsive
force |TG.sub.t|, but is preferably less than that engine speed. In
a lateral maneuvering operation for anchorage and moorage, the
directions of the propulsive forces generated by the outboard
motors 11, 12 are significantly different from the movement
direction of the hull 2 and, therefore, the engines 39 of the
outboard motors 11, 12 are operated at high engine speeds in spite
of the fact that the combined propulsive force |TG| is relatively
small. Therefore, a loud engine sound arouses unnatural or
uncomfortable feeling in the operator and the crew during the
lateral maneuvering operation.
[0233] In this preferred embodiment, the target combined propulsive
force generated by the stationary marine vessel maneuvering support
controlling section 27 is associated with the engine speed of the
port-side outboard motor 11. Therefore, the operator's unnatural
feeling and the crew's uncomfortable feeling attributable to the
loud engine sound are prevented.
[0234] While two preferred embodiments of the present invention
have thus been described, the present invention may be embodied in
many other ways. In the preferred embodiments described above, it
is assumed that the instantaneous center G of the hull 2 varies.
However, where the instantaneous center G is considered to be
virtually fixed, the construction of the marine vessel maneuvering
supporting apparatus and the control method are simplified. More
specifically, the target steering angle basic value .phi..sub.t in
the stationary marine vessel maneuvering support mode or the
moorage support mode may be fixed at a value which is determined by
a geometrical relationship between the instantaneous center G and
the propulsive force generating positions of the outboard motors
11, 12 (to coincide the action point F with the instantaneous
center G). In this case, the construction of the marine vessel
maneuvering supporting apparatus and the control method are further
simplified.
[0235] The propulsive forces are controlled by controlling the
outputs of the engines 39 in the preferred embodiments described
above. However, the propulsive forces may be controlled by using
propulsion systems including a variable pitch propeller whose
propeller angle (pitch) is controllable. In this case, target
pitches of the variable pitch propellers are calculated according
to target propulsive forces, and the pitches of the variable pitch
propellers are set at the target pitches thus calculated.
[0236] Although the preferred embodiments described above are
directed to the marine vessel 1 including two outboard motors 11,
12, the marine vessel 1 may further include a third outboard motor
provided on the center line 5 of the hull 2.
[0237] While the present invention has been described in detail
with reference to the preferred embodiments thereof, it should be
understood that the foregoing disclosure is merely illustrative of
the technical principles of the present invention but not
limitative of the same. The spirit and scope of the present
invention are to be limited only by the appended claims.
[0238] This application corresponds to Japanese Patent Application
No. 2003-418421 filed with the Japanese Patent Office on Dec. 16,
2003, the disclosure of which is incorporated herein by
reference.
* * * * *