U.S. patent application number 14/709522 was filed with the patent office on 2015-11-19 for oscillating foil propulsion system and method for controlling a motion of an oscillating movable foil.
The applicant listed for this patent is ABB Oy. Invention is credited to Sabyasachi Gosh Dastidar, Dawei Feng, Esa Jaakkola, Rachit Jain, Rahul Kallada Janardhan, Ville Kallis, Inka Luhtanen, H. Mangkhankhual, Jurgen Neubauer, Ville Pyotsia, Pontus Salminen.
Application Number | 20150329186 14/709522 |
Document ID | / |
Family ID | 50735901 |
Filed Date | 2015-11-19 |
United States Patent
Application |
20150329186 |
Kind Code |
A1 |
Feng; Dawei ; et
al. |
November 19, 2015 |
Oscillating foil propulsion system and method for controlling a
motion of an oscillating movable foil
Abstract
The invention relates to an oscillating foil propulsion system
comprising a movable foil, a pitch mechanism connected to the
movable foil and configured to control a pitch motion of the foil,
a heave mechanism connected to the movable foil and configured to
control a heave motion of the foil, and wherein at least one of the
pitch and heave mechanisms is configured to adjust an amplitude of
the respective motion of the movable foil. The invention further
relates to a method for controlling a motion of an oscillating
movable foil of a marine propulsion system.
Inventors: |
Feng; Dawei; (Espoo, FI)
; Dastidar; Sabyasachi Gosh; (Noida, IN) ;
Jaakkola; Esa; (Espoo, FI) ; Jain; Rachit;
(IIT Kanpur, IN) ; Janardhan; Rahul Kallada;
(Saroornagar, IN) ; Kallis; Ville; (Helsinki,
FI) ; Luhtanen; Inka; (Helsinki, FI) ;
Mangkhankhual; H.; (IIT Kanpur, IN) ; Neubauer;
Jurgen; (Gnas, AT) ; Pyotsia; Ville;
(Helsinki, FI) ; Salminen; Pontus; (Helsinki,
FI) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
ABB Oy |
Helsinki |
|
FI |
|
|
Family ID: |
50735901 |
Appl. No.: |
14/709522 |
Filed: |
May 12, 2015 |
Current U.S.
Class: |
416/1 ;
416/79 |
Current CPC
Class: |
B63H 1/36 20130101 |
International
Class: |
B63H 1/36 20060101
B63H001/36 |
Foreign Application Data
Date |
Code |
Application Number |
May 14, 2014 |
EP |
14168271.6 |
Claims
1. An oscillating foil propulsion system comprising: a movable
foil, a pitch mechanism connected to the movable foil and
configured to control a pitch motion of the foil, and a heave
mechanism connected to the movable foil and configured to control a
heave motion of the foil, wherein at least one of the pitch and
heave mechanisms is configured to adjust an amplitude of the
respective motion of the movable foil.
2. The oscillating foil propulsion system according to claim 1,
wherein the pitch mechanism is configured to adjust a pitch angle
of the pitch motion of the foil.
3. The oscillating foil propulsion system according to claim 1,
wherein the pitch mechanism is configured to cause the amplitude of
the pitch motion to change from a first peak amplitude to a
substantially different peak amplitude.
4. The oscillating foil propulsion system according to claim 3,
wherein the substantially different peak amplitude is greater than
or less than the first peak amplitude by 5-70 degrees.
5. The oscillating foil propulsion system according to claim 1,
wherein the pitch mechanism is further configured to adjust a
frequency of the pitch motion of the foil.
6. The oscillating foil propulsion system according to claim 1,
wherein the heave mechanism is configured to adjust a heave of the
heave motion of the foil.
7. The oscillating foil propulsion system according to claim 6,
wherein the heave mechanism is configured to cause the amplitude of
the heave motion to change from a first peak amplitude to a
substantially different peak amplitude.
8. The oscillating foil propulsion system according to any of claim
1, wherein the heave mechanism is further configured to adjust a
frequency of the heave motion.
9. The oscillating foil propulsion system according to claim 1,
wherein at least one of the pitch mechanism and the heave mechanism
includes a crank mechanism.
10. The oscillating foil propulsion system according to claim 9,
wherein the crank mechanism includes a crank arm, which is
rotatable around an axis of rotation, and wherein the length of the
crank arm is adjustable or the crank arm includes a coupling which
is movable along the crank arm.
11. The oscillating foil propulsion system according to claim 1,
wherein at least one of the pitch mechanism and the heave mechanism
includes hydraulic cylinders and/or the heave mechanism includes a
rack and a movable base module.
12. The oscillating foil propulsion system according to claim 1,
wherein at least a portion of the pitch mechanism and at least a
portion of the heave mechanism are configured to be housed within a
hull of a vessel and wherein the movable foil is configured to be
outside of the hull of the vessel.
13. The oscillating foil propulsion system according to claim 1,
wherein the oscillating foil propulsion system is partially housed
within a azimuthing housing, and wherein a connector extends from
outside the azimuthing housing to inside the housing and wherein
the movable foil is configured to be outside of the azimuthing
housing.
14. The oscillating foil propulsion system according to claim 1,
further comprising a computer readable medium having stored thereon
a set of computer implementable instructions capable of causing a
processor, in connection with the pitch mechanism, to control a
pitch angle of the movable foil, a frequency of the pitch motion,
and an amplitude of the pitch motion.
15. The oscillating foil propulsion system according to claim 1,
further comprising a computer readable medium having stored thereon
a set of computer implementable instructions capable of causing a
processor, in connection with the heave mechanism, to control a
heave of the movable foil, a frequency of the heave motion, and an
amplitude of the heave motion.
16. A method for controlling a motion of an oscillating movable
foil of a marine propulsion system, comprising the steps of:
varying an amplitude of a pitch motion of the movable foil to
change from a first peak amplitude to a substantially different
peak amplitude, and/or varying an amplitude of a heave motion of
the movable foil to change from a first peak amplitude to a
substantially different peak amplitude.
17. The method according to claim 16, further comprising: receiving
at least one input, said input selected from the group of: a speed
of a vessel, a direction of a local fluid flow in relation to the
movable foil, a velocity of a local fluid flow in relation to the
movable foil, and a desired thrust of the vessel, and wherein at
least one of the amplitude of the pitch motion and the amplitude of
the heave motion is varied based on said at least one input.
18. A non-transitory computer readable medium having stored thereon
a set of computer implementable instructions capable of causing a
computing device, in connection with a pitch mechanism capable of
controlling a pitch motion of a movable foil and a heave mechanism
capable of controlling a heave motion of the movable foil, to vary
an amplitude of at least one of the pitch motion and the heave
motion of the foil of an oscillating foil propulsion system.
19. The non-transitory computer readable medium according to claim
18 capable of causing the computing device to vary at least one of
a pitch angle, a heave, a frequency of the pitch motion, a
frequency of the heave motion, the amplitude of the pitch motion,
and the amplitude of the heave motion depending on at least one of:
a speed of a vessel, a direction of a local fluid flow in relation
to the movable foil, a velocity of the local fluid flow in relation
to the movable foil, and a desired thrust of the vessel.
20. (canceled)
Description
TECHNICAL FIELD OF THE INVENTION
[0001] The present invention relates to a marine propulsion system,
in particular to an oscillating foil propulsion system. The present
invention further relates to a method for controlling a motion of
an oscillating movable foil of a marine propulsion system.
Furthermore, the invention relates to a computer readable medium
having stored thereon a set of computer implementable instructions.
Additionally, the invention relates to a computer program.
BACKGROUND OF THE INVENTION
[0002] Many different marine propulsion devices for use in a fluid
are known, by means of which a vessel can be propelled or propelled
and steered. Typical propulsion systems include, for example, side
paddle wheels, conventional screw propellers, podded propulsion
devices, vertical axis propellers, sails, kite sails, or Flettner
rotors.
[0003] Presently, vessels, especially cargo vessels, are usually
equipped with at least one screw propeller for propulsion. The
efficiency of the propeller is typically about 60%-70%. Further
optimization of conventional screw propellers has become more
difficult and therefore new propulsive devices are needed, which,
for example, produce thrust by a movement of an oscillating fin,
which mimics the manner in which dolphins or whales swim. The
efficiency of such sea animals has been estimated to be greater
than 70%. Theoretical fin propulsion has been widely studied in the
past and new fin propulsion systems may, for example, lead to
achievement of a greater propulsor efficiency compared to a
conventional propeller.
[0004] The document US 2011/0255971 A1, which is considered to be
the closest prior art, discloses an apparatus for oscillating a
foil in a fluid. The apparatus comprises a first crank mechanism
and a second crank mechanism connected to a foil. Said first crank
mechanism and said second crank mechanism have different crank pin
offsets, are functionally connected such that when driven the speed
of revolution of said first crank mechanism is the same as the
speed of revolution of said second crank mechanism, and are out of
phase with each other.
[0005] The crankshaft of the first crank mechanism is rotatable
about a first axis of rotation and having a first crank pin offset
relative to said first axis of rotation. The crankshaft of the
second crank mechanism is rotatable about a second axis of rotation
and having a second crank pin offset relative to said second axis
of rotation. The length of the first and second crankshaft is
constant and not adjustable. Therefore, the apparatus according to
document US 2011/0255971 A1 allows adjustment of the frequency of
the sinusoidal like pitch and heave motion of the foil by adjusting
the speed of revolution of the crank mechanisms, but does not allow
controlled adjustment of the peak amplitude of the pitch and heave
motion, for example, to adjust the angle of attack depending on the
direction and velocity of the oncoming local fluid flow in the foil
working area.
SUMMARY OF THE INVENTION
[0006] It is an object of certain embodiments of the present
invention to provide an oscillating foil propulsion system. It is a
further object of certain embodiments of the present invention to
provide a method for controlling a motion of an oscillating movable
foil of a marine propulsion system.
[0007] According to certain embodiments, there is described a
marine propulsion system by means of which a vessel can be
propelled. According to certain embodiments, there is further
described a propulsive device, which implements aspects of the
movement of a fin of an animal, such as a whale or a dolphin,
wherein the required motion of the propulsion system is
controllable and adjustable.
[0008] These and other objects are achieved by the present
invention, as hereinafter described and claimed. Thus the invention
concerns an oscillating foil propulsion system comprising a movable
foil, a pitch mechanism connected to the movable foil and
configured to control a pitch motion of the foil, a heave mechanism
connected to the movable foil and configured to control a heave
motion of the foil, and wherein at least one of the pitch and heave
mechanisms is configured to adjust an amplitude of the respective
motion of the movable foil.
[0009] The pitch mechanism is configured to adjust a pitch angle of
the pitch motion of the foil. The pitch mechanism is configured to
cause the amplitude of the pitch motion to change from a first peak
amplitude to a substantially different peak amplitude. The
substantially different peak amplitude is preferably greater than
or less than the first peak amplitude by 5-70 degrees, more
preferably by 10-60 degrees. The pitch mechanism is preferably
further configured to adjust a frequency of the pitch motion of the
foil.
[0010] The heave mechanism is configured to adjust a heave of the
heave motion of the foil. The heave mechanism is configured to
cause the amplitude of the heave motion to change from a first peak
amplitude to a substantially different peak amplitude. The heave
mechanism is preferably further configured to adjust a frequency of
the heave motion.
[0011] At least one of the pitch mechanism and the heave mechanism
preferably includes a crank mechanism to control the amplitude of
the pitch and/or heave motion. The crank mechanism preferably
includes a crank arm, which is rotatable around an axis of
rotation, and wherein the length of the crank arm is adjustable.
Otherwise, the crank mechanism preferably includes a crank arm,
which is rotatable around an axis of rotation, and a coupling which
is movable along the crank arm. The coupling of the crank mechanism
preferably includes a crank pin which is located at an adjustable
distance from the axis of rotation. The pitch mechanism preferably
includes a crank mechanism having a pitch rod. The pitch rod is
then connected to a coupling of the pitch mechanism. The heave
mechanism preferably includes a crank mechanism having a heave rod.
The heave rod is then connected to a coupling of the heave
mechanism. Otherwise, at least one of the pitch mechanism and the
heave mechanism preferably includes hydraulic cylinders instead of
a crank mechanism to control the amplitude of the pitch and/or
heave motion. The amplitudes of the pitch and heave motion may be
preferably also controlled by means of a rack and base module
assembly, wherein the base module is linearly movable along the
rack and at least one movable foil is connected to the base
module.
[0012] The pitch mechanism preferably includes a pitch slider,
which is connected to the pitch mechanism's crank mechanism, and
wherein the pitch slider is linearly movable. The heave mechanism
preferably includes a heave slider, which is connected to the heave
mechanism's crank mechanism, and wherein the heave slider is
linearly movable. At least one of the pitch mechanism and heave
mechanism is preferably connected to the movable foil by a
connector including at least one cam which includes pinions. The
respective pitch or heave slider of said pitch mechanism and/or
heave mechanism then includes rack pinions. The pinions of the cam
are then coupled to said rack pinions. Otherwise, the pitch
mechanism and the heave mechanism are preferably connected to the
movable foil by at least one connector including a crank mechanism.
The crank mechanism of the connector is then coupled to a pitch
slider, a heave slider, and the movable foil.
[0013] At least a portion of the pitch mechanism and at least a
portion of the heave mechanism are preferably configured to be
housed within a hull of a vessel. The movable foil is configured to
be outside of the hull of the vessel. Otherwise, the oscillating
foil propulsion system is partially housed within a azimuthing
housing. The connector extends then from outside the azimuthing
housing to inside the housing.
[0014] The oscillating foil propulsion system is preferably further
comprising a computer readable medium having stored thereon a set
of computer implementable instructions capable of causing a
processor, in connection with the pitch mechanism, to control a
pitch angle of the movable foil, a frequency of the pitch motion,
and an amplitude of the pitch motion. Additionally, the oscillating
foil propulsion system is preferably further comprising a computer
readable medium having stored thereon a set of computer
implementable instructions capable of causing a processor, in
connection with the heave mechanism, to control a heave of the
movable foil, a frequency of the heave motion, and an amplitude of
the heave motion.
[0015] The invention further concerns a method for controlling a
motion of an oscillating movable foil of a marine propulsion
system, comprising the steps of:
[0016] varying an amplitude of a pitch motion of the movable foil
to change from a first peak amplitude to a substantially different
peak amplitude, and/or
[0017] varying an amplitude of a heave motion of the movable foil
to change from a first peak amplitude to a substantially different
peak amplitude.
[0018] The method is preferably further comprising:
[0019] receiving at least one input, said input selected from the
group of: a speed of a vessel, a direction of a local fluid flow in
relation to the movable foil, a velocity of a local fluid flow in
relation to the movable foil, and a desired thrust of the vessel,
and
[0020] wherein at least one of the amplitude of the pitch motion
and the amplitude of the heave motion is varied based on said at
least one input.
[0021] The invention furthermore concerns a computer readable
medium having stored thereon a set of computer implementable
instructions capable of causing a computing device, in connection
with a pitch mechanism capable of controlling a pitch motion of a
movable foil and a heave mechanism capable of controlling a heave
motion of the movable foil, to vary an amplitude of at least one of
the pitch motion and the heave motion of the foil of an oscillating
foil propulsion system.
[0022] The computer readable medium is preferably capable of
causing the computing device to vary at least one of a pitch angle,
a heave, a frequency of the pitch motion, a frequency of the heave
motion, the amplitude of the pitch motion, and the amplitude of the
heave motion depending on at least one of:
[0023] a speed of a vessel,
[0024] a direction of a local fluid flow in relation to the movable
foil,
[0025] a velocity of the local fluid flow in relation to the
movable foil, and
[0026] a desired thrust of the vessel.
[0027] Additionally, the invention concerns a computer program
configured to cause a method in accordance with at least one of
claims 16-17 to be performed.
[0028] Considerable advantages are obtained by means of the present
invention. A vessel, for example a cargo vessel or a passenger
vessel, can be propelled by means of the propulsion system
according to the invention. The propulsion system implements
aspects of the movement of an animal, such as a whale or a dolphin,
and the required motion of the at least one foil is more natural,
continuously controllable and adjustable by modification of
parameters. Such parameters include the pitch angle, the heave, the
frequency of the heave motion, the frequency of the pitch motion,
the amplitude of the heave motion, the amplitude of the pitch
motion, and the phase difference between pitch and heave. The
motion of the foil can be optimized by means of controlled
adjustment of the amplitude of the pitch motion and/or the
amplitude of the heave motion of the foil, for example, depending
on the speed of the vessel, the direction of a local fluid flow,
the velocity of a local fluid flow and/or a desired thrust.
[0029] The present invention especially improves the propulsor
efficiency of the foil over prior art. The efficiency improvement
leads to reduced fuel consumption of the vessel and therefore to a
longer maximum range as well as reduced emissions. Another
advantage is the possibility to reduce the volume of the fuel tanks
which increases the space for valuable payload on board. A
combination of the aforementioned advantages, i.e. reduction of
fuel consumption and reduction of fuel tank volume, is also
possible.
[0030] Additionally, model tests of a propulsion system according
to an embodiment of the invention have indicated that a propulsor
efficiency of 50%-70% or greater can be achieved, which is in the
range of or significantly greater than the efficiency of a
conventional propeller. The wetted propulsion surface of the at
least one foil can be larger than the area of a conventional
propeller which reduces the area load. The propulsion system is
especially suited for so called horizontally positioned foils
having a large aspect ratio in order to achieve advantageous lift
and drag coefficients. In addition, the propulsion system according
to the invention is suitable for vessels with limited draught, for
example inland navigation vessels. The hydrofoil further reduces
noise and vibrations.
[0031] Furthermore, the propulsion system according to certain
embodiments of the invention does not include any connecting rods
which are arranged in vertical direction outside the vessel. In
absence of vertical connecting rods the strength and stability of
the propulsion system can be improved over prior art. Due to the
orientation of the at least one connector, which is not arranged in
an essentially vertical direction, impact forces in case of an
collision of the connector with another object will be minimized.
This reduces the risk of damaging the propulsion system or of a
total system failure and therefore improves safety of a vessel
during operation over prior art.
BRIEF DESCRIPTION OF THE DRAWINGS
[0032] For a more complete understanding of particular embodiments
of the present invention and their advantages, reference is now
made to the following descriptions, taken in conjunction with the
accompanying drawings. In the drawings:
[0033] FIG. 1 illustrates a schematic view of a propulsion system
according to a first embodiment of the invention,
[0034] FIG. 2 illustrates a schematic view of a propulsion system
according to a second embodiment of the invention,
[0035] FIG. 3 illustrates a schematic view of a crank mechanism of
a pitch or heave mechanism of a propulsion system according to a
third embodiment of the invention,
[0036] FIG. 4 illustrates a schematic view of a propulsion system
according to a fourth embodiment of the invention,
[0037] FIG. 5 illustrates a schematic view of a part of a vessel
which is equipped with two propulsion systems according to a fifth
embodiment of the invention,
[0038] FIG. 6 illustrates a schematic time-angle/vertical
position-diagram of the pitch and heave motion of a propulsion
system according to a sixth embodiment of the invention, wherein
the amplitudes of the pitch motion and the heave motion are
decreasing,
[0039] FIG. 7 illustrates a schematic time-angle/vertical
position-diagram of the pitch and heave motion of a propulsion
system according to a seventh embodiment of the invention, wherein
the amplitudes of the heave motion are increasing,
[0040] FIG. 8 illustrates a schematic time-angle/vertical
position-diagram of the pitch and heave motion of a propulsion
system according to an eighth embodiment of the invention, wherein
the amplitudes of the pitch motion are decreasing,
[0041] FIG. 9 illustrates a schematic time-angle/vertical
position-diagram of the pitch and heave motion of a propulsion
system according to a ninth embodiment of the invention, wherein
the foil is high loaded, and
[0042] FIG. 10 illustrates a schematic time-angle/vertical
position-diagram of the pitch and heave motion of a propulsion
system according to a tenth embodiment of the invention, wherein
the load of the foil is relatively small.
DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION
[0043] In FIG. 1 a schematic view of a propulsion system 1
according to a first embodiment of the invention is illustrated.
The propulsion system 1 includes a movable foil 2 which is arranged
in a fluid 3 outside a body 4. The system 1 further includes a
pitch mechanism 5 for adjusting a pitch angle .alpha.(t) between
the chord line c of the foil 2 and a horizontal plane HP, a
frequency f.sub.1(t) of the pitch motion, and an amplitude
A.sub.1(t) of the pitch motion of the movable foil 2. The system 1
also includes a heave mechanism 6 for adjusting a heave h(t) of the
movable foil in vertical direction, a frequency f.sub.2(t) of the
heave motion, and an amplitude A.sub.2(t) of the heave motion of
the movable foil 2. The pitch and heave mechanisms 5, 6 are
arranged inside the body 4. A connector 7 is extending from outside
the body 4 to inside the body 4 and is connected to and adapted to
interact with the pitch mechanism 5, the heave mechanism 6 and the
movable foil 2. The movable foil may have a symmetrical or
asymmetrical profile. The aspect ratio of the movable foil 2 is
preferably greater than 2 or 3, even more preferably greater than 4
or 5 in order to provide advantageous lift coefficients of the
movable foil 2. The movable foil 2 may further be equipped with so
called end plates or winglets. The system 1 is adapted to modify at
least one of the pitch angle .alpha.(t), the heave h(t), the
frequency f.sub.1(t) of the pitch motion, the frequency f.sub.2(t)
of the heave motion, the amplitude A.sub.1(t) of the pitch motion,
the amplitude A.sub.2(t) of the heave motion, and a phase
difference .DELTA..sub.P(t) between pitch and heave. The maximum
pitch angles .alpha.(t), i.e. the peak amplitudes A.sub.1(t) of the
movable foil 2, are typically in the range between +70.degree. and
-70.degree. from the horizontal plane HP. Other embodiments may
include other maximum pitch angles .alpha.(t) of the at least one
foil 2, for example+60.degree. and -60.degree., +45.degree. and
-45.degree., +35.degree. and -35.degree., or any other pitch angles
.alpha.(t). Maximum positive and negative pitch angles .alpha.(t)
of the foil 2 may be further equal or different. The maximum
frequency f.sub.1(t) of the pitch motion and the maximum frequency
f.sub.2(t) of the heave motion is typically less than 3 Hz.
[0044] In FIG. 2 a schematic view of a propulsion system 1
according to a second embodiment of the invention is illustrated.
The propulsion system 1 includes a movable foil 2, which is
arranged in a fluid 3 outside a body 4. The system 1 further
includes a pitch mechanism 5 for adjusting a pitch angle
.alpha.(t), a frequency f.sub.1(t) of the pitch motion, and an
amplitude A.sub.1(t) of the pitch motion of the movable foil 2 and
a heave mechanism 6 for adjusting a heave h(t), a frequency
f.sub.2(t) of the heave motion, and an amplitude A.sub.2(t) of the
heave motion of the movable foil 2. The pitch and heave mechanisms
5, 6 are arranged inside the body 4. The pitch mechanism 5 includes
a first crank mechanism 8, a movable pitch slider 9 which is
connected to the first crank mechanism 8 on one side, and rack
pinions 10 which are connected to, arranged on, or an integral part
of the pitch slider 9. The heave mechanism 6 includes a second
crank mechanism 11, a movable heave slider 12 which is connected to
the second crank mechanism 11 on one side, and rack pinions 10
which are connected to, arranged on, or an integral part of the
heave slider 12. A connector 7 is further extending from outside
the body 4 to inside the body 4. The connector 7 includes two
separate cams 13 inside the body 4, which each include pinions 14,
which are coupled to and adapted to interact with the rack pinions
10 of the movable pitch slider 9 of the pitch mechanism 5 and the
rack pinions 10 of the movable heave slider 12 of the heave
mechanism 6, respectively. The connector 7 is outside the body 4
connected to and adapted to interact with the movable foil 2. The
connector 7 for transmitting the heave motion may be hollow so that
a mechanism for the adjustment of the pitch motion is arranged
inside the connector 7. The system 1 is further comprising a
computer readable medium having stored thereon a set of computer
implementable instructions capable of causing a processor, in
connection with the pitch mechanism and/or heave mechanism, to
control the pitch angle .alpha.(t), the heave h(t), the frequency
f.sub.1 (t) of the heave motion, the frequency f.sub.2(t) of the
pitch motion, the amplitude A.sub.1(t) of the heave motion, the
amplitude A.sub.2(t) of the pitch motion, and the phase difference
.DELTA..sub.P(t) between pitch and heave. The system may further
include sensors or measurement devices for measuring parameters,
such as the pitch angle .alpha.(t), the heave h(t), the frequency
f.sub.1(t) of the heave motion, the frequency f.sub.2(t) of the
pitch motion, the amplitude A.sub.1 (t) of the heave motion, the
amplitude A.sub.2(t) of the pitch motion, or the velocity of the
local fluid flow in the foil working area. The propulsion system 1
is especially suited for so called horizontally positioned
foils.
[0045] In FIG. 3 a schematic view of a crank mechanism 8, 11 of a
pitch or heave mechanism 5, 6 of a propulsion system 1 according to
a third embodiment of the invention is illustrated. At least one
power source, which is not shown in FIG. 3, provides the first or
second crank mechanism 8, 11 with rotational power which is
transmitted to a rotating crank arm 16 which is rotatable about a
first axis of rotation 17 or a fourth axis of rotation 23,
respectively, and having a first crank pin 18 or a third crank pin
26, respectively, which is linearly movable in the longitudinal
direction of the rotating crank arm 16. The first crank pin 18
represents the second axis of rotation 19 and the third crank pin
26 represents the fifth axis of rotation 24, respectively. A pitch
rod 20 is rotatably connected at one end to said first crank pin 18
about the second axis of rotation 19 or a heave rod 30 is rotatably
connected at one end to said third crank pin 26 about the fifth
axis of rotation 24, respectively. A pitch slider 9 is connected at
one end to a second crank pin 21 about the third axis of rotation
22 or a heave slider 12 is connected at one end to a fourth crank
pin 27 about a sixth axis of rotation 25, respectively. Contrary to
prior art, in addition to the rotation of the crank arm 16 about
the first axis of rotation 17 or the fourth axis of rotation 23,
the position of the first crank pin 18 or the third crank pin 26
can be linearly adjusted relative to the first axis of rotation 17
or the fourth axis of rotation 23 by an actuator. In other words,
contrary to prior art, the rotating radius r(t) of the second axis
of rotation 19 or the fifth axis of rotation 24 relative to the
first axis of rotation 17 or the fourth axis of rotation 23 can be
adjusted, i.e. the amplitude A.sub.1(t) of the pitch motion or the
amplitude A.sub.2(t) of the heave motion can be controlled with the
help of the crank mechanisms 8, 11. A small rotating radius r(t) of
the second axis of rotation 17 equals a small amplitude A.sub.1(t)
of the pitch motion and a small rotating radius r(t) of the fifth
axis of rotation 24 equals a small amplitude A.sub.2(t) of the
heave motion and vice versa. The frequency f.sub.1(t) of the pitch
motion and the frequency f.sub.2(t) of the heave motion can be
varied by adjusting the speed of revolution of the crank arm 16 of
the crank mechanisms 8, 11.
[0046] In FIG. 4 a schematic view of a propulsion system 1
according to a fourth embodiment of the invention is illustrated.
The propulsion system 1 includes a movable foil 2, which is
arranged in a fluid 3 outside a body 4. The system 1 further
includes a pitch mechanism 5 for adjusting a pitch angle
.alpha.(t), a frequency f.sub.1(t) of the pitch motion, and an
amplitude A.sub.1(t) of the pitch motion of the foil 2 and a heave
mechanism 6 for adjusting a heave h(t), a frequency f.sub.2(t) of
the heave motion, and an amplitude A.sub.2(t) of the heave motion
of the foil 2. The pitch and heave mechanisms 5, 6 are arranged
inside the body 4 and each includes a crank mechanism 8, 11. The
first crank mechanism 8 of the pitch mechanism 5 is providing the
movement to the pitch motion and the second crank mechanism 11 of
the heave mechanism 6 is providing the movement to the heave
motion. A rotation of the second axis of rotation 19 about the
first axis of rotation 17 of the pitch mechanism 5 together with a
rotation of the fifth axis of rotation 24 about the fourth axis of
rotation 23 of the heave mechanism 6 would result in a simultaneous
pitch and heave motion of the foil 2. The crank mechanisms 8, 11 of
the pitch and heave mechanisms 5, 6 are out of phase with each
other. The phase angle of the pitch and heave motion is adjusted by
the angle difference .DELTA..sub.P(t) of the crank arms 16. The
rotation of the crank arm 16 of the first crank mechanism 8 leads
to a linear movement of the pitch slider 9 via the first crank pin
18, the pitch rod 20 and the second crank pin 21. The rotation of
the crank arm 16 of the second crank mechanism 11 leads to a linear
movement of the heave slider 12 via the third crank pin 26, the
heave rod 30 and the fourth crank pin 27. Both sliders 9, 12 are
supported by sliding bearings 28, 29. The pitch slider 9 is further
rotatable connected to a lower pitch rod 31 about a seventh axis of
rotation 32 via a fifth pin 33 and the heave slider 12 is rotatable
connected to a lower heave rod 34 about an eighth axis of rotation
35 via a sixth pin 36. Additionally, a connector 7 is extending
from outside the body 4 to inside the body 4. The connector 7
includes a third crank mechanism and is connected to and adapted to
interact with the lower pitch rod 31 of the pitch mechanism 5 via a
pitch lever 37, with the lower heave rod 34 of the heave mechanism
6 via a heave lever 46 and with the foil 2 via the hydrofoil crank
47. The pitch lever 37 of the third crank mechanism is rotatable
connected to one end of the lower pitch rod 31 about a ninth axis
of rotation 38 via a seventh pin 39 and rotatable connected to one
end of a pitch crank 40 about a tenth axis of rotation 41 via an
eighth pin 42. The pitch crank 40 of the third crank mechanism is
further rotatable connected to a heave connecting rod 43 about an
eleventh axis of rotation 44 via an ninth pin 45. The heave
connecting rod 43 is rotatable connected to a heave crank 48 about
a twelfth axis of rotation 49 via a tenth pin 50. The heave crank
48 is rotatable connected to the connecting rod 7 about a
thirteenth axis of rotation 51 via an eleventh pin 52. The third
crank mechanism also includes the heave lever 46, which is
rotatable connected via the eleventh pin 52 to the connecting rod
7. The other side of the heave lever 46 is rotatable connected to
the lower heave rod 34 about a fourteenth axis 53 of rotation via a
twelfth pin 54. Additionally, the heave crank 48 is also rotatable
connected via the tenth pin 50 to a hydrofoil connecting rod 55.
The hydrofoil connecting rod 55 is rotatable connected to the
hydrofoil crank 47 about a fifteenth axis of rotation 56 via a
thirteenth pin 57. The hydrofoil crank 47 is then rotatable
connected to the foil 2 about a sixteenth axis of rotation 58 via a
fourteenth pin 59. The propulsion system 1 is especially suited for
so called horizontally positioned foils.
[0047] According to other embodiments of the invention the pitch
mechanism 5 may include two or more hydraulic cylinders instead of
the crank mechanism 8. The heave mechanism 6 may also include two
or more hydraulic cylinders instead of the crank mechanism 11. The
hydraulic cylinders are configured to control the pitch angle
.alpha.(t), the frequency f.sub.1(t) of the pitch motion, and the
amplitude A.sub.1(t) of the pitch motion and/or the heave h(t), the
frequency f.sub.2(t) of the heave motion, and the amplitude
A.sub.2(t) of the heave motion. According to further embodiments of
the invention at least one rack may be fixedly attached to the
stern of a hull 61 of a vessel 60. A base module, which is movable
in vertical direction along the rack and configured to control the
heave h(t), the frequency f.sub.2(t) of the heave motion, and the
amplitude A.sub.2(t) of the heave motion of the movable foil 2, is
then connected to the rack. In this case at least one movable foil
2 is further connected to the base module. Preferably, one movable
foil 2 is connected on the starboard side and one movable foil 2 is
connected on the port side of the movable base module. The movable
base module may preferably include the pitch mechanism 5 which is
configured to control the pitch angle .alpha.(t), the frequency
f.sub.1(t) of the pitch motion, and the amplitude A.sub.1 (t) of
the pitch motion of the movable foil 2. According to another
embodiment of the invention the pitch mechanism and the heave
mechanism may, for example, also include connecting rods which are
arranged in an essentially vertical direction and connected to the
crank mechanisms or the hydraulic cylinders at one end as well as
to the movable foil 2 at the other end. The connecting rods then
extend from outside the vessel 60 to inside the hull 61 of the
vessel 60 and transmit the required motion to the movable foil 2.
The connecting rods may be preferably arranged in a streamlined
enclosure to reduce the resistance of the propulsion system 1.
[0048] In FIG. 5 a schematic view of a part of a vessel 60 which is
equipped with two propulsion systems 1 according to a fifth
embodiment of the invention is illustrated. The propulsion systems
1 each include two movable foils 2 which are arranged in a fluid 3
outside the vessel 60. The pitch and heave mechanisms 5, 6 of the
foils 2, which are not shown in FIG. 4, are arranged inside the
body 4. Connectors 7 are extending from outside the body 4 to
inside the body 4 and are each connected to the pitch mechanism 5,
to the heave mechanism 6 and to the foils 2. Only one seal is
required for each connector 7 at the position where the connector 7
extends from outside the hull 61 to inside the hull 61. The two
propulsion systems 1 may be controlled by one or more computing
devices 15 with an implemented computer aided algorithm stored
thereon. The local fluid flow in transversal direction in the foil
working area is in particular depending on the service speed, the
hullform, and the form of the connector 7 of the vessel 60.
According to other embodiments of the invention the pitch and heave
mechanism 5, 6 may be arranged inside a submerged azimuthing
housing, which is connected to a steering module, which is to be
installed in the hull 61 of the vessel 60. With the help of such a
propulsion system 1 it would be possible to direct the desired
thrust into any direction. In other words, such a propulsion system
1 which can rotate in an essentially horizontal plane around
360.degree. can be also used for steering a vessel 60.
[0049] In FIG. 6 a time-angle/vertical position-diagram of the
pitch and heave motion of a propulsion system according to a sixth
embodiment of the invention is illustrated. The diagram represents
an acceleration of a vessel from zero speed up to a desired service
speed. The peak amplitudes A.sub.1(t) of the pitch motion and the
peak amplitudes A.sub.2(t) of the heave motion are continuously or
step-wise decreased after starting until the desired service speed
of the vessel is reached. The system is configured to cause the
pitch angle .alpha.(t) and the heave h(t) to change its range of
oscillation from a first range to a second range. When starting,
especially large heave amplitudes A.sub.1(t) are necessary to
create a local fluid flow in the foil working area. With increasing
service speed of the vessel the oncoming local fluid flow in the
foil working area is changing from a rather vertical direction to a
more horizontal direction and therefore continuous or step-wise
reduction of the peak amplitudes A.sub.1(t) of the pitch motion is
advantageous in order to provide sufficient angles of attack. When
reaching the desired service speed, the at least one foil is
controlled such that the peak amplitudes A.sub.1(t) of the
sinusoidal like pitch angle function .alpha.(t) and the peak
amplitudes A.sub.2(t) of the sinusoidal like heave function h(t)
are constant. Contrary to prior art, the effect of the change of
the direction and velocity of the local fluid flow in the foil
working area on the angle of attack during acceleration of the
vessel can be considered which leads to a thrust and efficiency
improvement of the propulsion system. The peak amplitudes A.sub.1
(t) of the pitch motion and the peak amplitudes A.sub.2(t) of the
heave motion are preferably continuously controlled such that an
optimum thrust is achieved and the maximum angle of attack is less
than a critical angle of attack in order to avoid stalling of the
movable foil. In FIG. 6 the peak amplitudes A.sub.1(t) of the pitch
motion and the peak amplitudes A.sub.2(t) of the heave motion are
continuously controlled depending on the speed of the vessel.
[0050] In FIG. 7 a time-angle/vertical position-diagram of the
pitch and heave motion of a propulsion system according to a
seventh embodiment of the invention is illustrated, wherein the
peak amplitudes A.sub.2(t) of the heave motion are increasing.
While the peak amplitudes A.sub.1(t) of the pitch motion are
constant during operation of the propulsion system, the peak
amplitudes A.sub.2(t) of the heave motion are increased to increase
the area load of the at least one foil. The system is configured to
cause the heave h(t) to change its range of oscillation from a
first range to a second range. The first range may, for example,
comprise a heave between +0.5 m and -0.5 m and the second range
may, for example, comprise a heave between +0.8 m and -0.8 m,
between +1.2 m and -1.2 m, or any other heave range. In FIG. 7 the
peak amplitudes A.sub.2(t) of the heave motion are controlled
depending on a temporarily desired thrust.
[0051] In FIG. 8 a time-angle/vertical position-diagram of the
pitch and heave motion of a propulsion system according to an
eighth embodiment of the invention is illustrated, wherein the peak
amplitudes A.sub.1(t) of the pitch motion are decreasing. While the
peak amplitudes A.sub.2(t) of the heave motion are constant during
operation of the propulsion system, the peak amplitudes A.sub.1(t)
of the pitch motion are decreased in order to optimize the angle of
attack of the at least one foil of the propulsion system. The
system is configured to cause the pitch angle .alpha.(t) to change
its range of oscillation from a first range to a second range. The
first range may, for example, comprise angles between +70.degree.
and -70.degree. and the second range may, for example, comprise
angles between +30.degree. and -30.degree., or any other angles. In
FIG. 8 the peak amplitudes A.sub.1(t) of the pitch motion are
continuously controlled depending on the direction and velocity of
a local fluid flow in the foil working area.
[0052] In FIG. 9 a time-angle/vertical position-diagram of the
pitch and heave motion of a propulsion system according to a ninth
embodiment of the invention is illustrated, wherein the movable
foil is high loaded. The peak amplitudes A.sub.2(t) of the heave
motion are constant during operation and at the system's maximum.
The peak amplitudes A.sub.1(t) of the pitch motion are also
constant during operation, but not at the system's maximum in order
to provide sufficient angles of attack.
[0053] In FIG. 10 a time-angle/vertical position-diagram of the
pitch and heave motion of a propulsion system according to a tenth
embodiment of the invention is illustrated, wherein the area load
of the movable foil is relatively small. The peak amplitudes
A.sub.1(t), A.sub.2(t) of the pitch motion and the heave motion are
constant during operation and not at the system's maximum.
Increasing the heave h(t) would increase the area load of the foil.
The peak amplitude A.sub.1(t) of the pitch motion is depending on
the direction and velocity of the oncoming local fluid flow in the
foil working area. Smaller angles of attack would reduce the area
load further.
[0054] Although the present invention has been described in detail
for the purpose of illustration, various changes and modifications
can be made within the scope of the claims. In addition, it is to
be understood that the present disclosure contemplates that, to the
extent possible, one or more features of any embodiment may be
combined with one or more features of any other embodiment.
[0055] It is to be understood that the embodiments of the invention
disclosed are not limited to the particular structures, process
steps, or materials disclosed herein, but are extended to
equivalents thereof as would be recognized by those ordinarily
skilled in the relevant arts. It should also be understood that
terminology employed herein is used for the purpose of describing
particular embodiments only and is not intended to be limiting.
[0056] The pitch angle .alpha.(t), the heave h(t), the frequency
f.sub.1(t) of the pitch motion, the frequency f.sub.2(t) of the
heave motion, the amplitude A.sub.1(t) of the pitch motion, the
amplitude A.sub.2(t) of the heave motion, the phase difference
.DELTA..sub.P(t) between pitch and heave, and the distance r(t) are
functions of time.
[0057] In general, the vertical direction is defined as being
perpendicular to the horizontal direction and the transversal
direction. The horizontal direction is further defined as being
perpendicular to the transversal direction. The horizontal
direction and the transversal direction form a horizontal plane. A
rotation of one of the aforementioned directions about at least one
axis of rotation leads to a rotation of the other two directions as
well as to a rotation of the horizontal plane about the at least
one axis of rotation within the meaning of the detailed description
of embodiments described above.
LIST OF REFERENCE NUMBERS
[0058] 1 propulsion system [0059] 2 foil [0060] 3 fluid [0061] 4
body [0062] 5 pitch mechanism [0063] 6 heave mechanism [0064] 7
connector [0065] 8 first crank mechanism [0066] 9 pitch slider
[0067] 10 rack pinions [0068] 11 second crank mechanism [0069] 12
heave slider [0070] 13 cam [0071] 14 pinions [0072] 15 computing
device [0073] 16 crank arm [0074] 17 first axis of rotation [0075]
18 first crank pin [0076] 19 second axis of rotation [0077] 20
pitch rod [0078] 21 second crank pin [0079] 22 third axis of
rotation [0080] 23 fourth axis of rotation [0081] 24 fifth axis of
rotation [0082] 25 sixth axis of rotation [0083] 26 third crank pin
[0084] 27 fourth crank pin [0085] 28 sliding bearing [0086] 29
sliding bearing [0087] 30 heave rod [0088] 31 lower pitch rod
[0089] 32 seventh axis of rotation [0090] 33 fifth pin [0091] 34
lower heave rod [0092] 35 eighth axis of rotation [0093] 36 sixth
pin [0094] 37 pitch lever [0095] 38 ninth axis of rotation [0096]
39 seventh pin [0097] 40 pitch crank [0098] 41 tenth axis of
rotation [0099] 42 eighth pin [0100] 43 heave connecting rod [0101]
44 eleventh axis of rotation [0102] 45 ninth pin [0103] 46 heave
lever [0104] 47 hydrofoil crank [0105] 48 heave crank [0106] 49
twelfth axis of rotation [0107] 50 tenth pin [0108] 51 thirteenth
axis of rotation [0109] 52 eleventh pin [0110] 53 fourteenth axis
of rotation [0111] 54 twelfth pin [0112] 55 hydrofoil connecting
rod [0113] 56 fifteenth axis of rotation [0114] 57 thirteenth pin
[0115] 58 sixteenth axis of rotation [0116] 59 fourteenth pin
[0117] 60 vessel [0118] 61 hull [0119] A.sub.1(t) amplitude of
pitch motion [0120] A.sub.2(t) amplitude of heave motion [0121] c
chord line [0122] f.sub.1 (t) frequency of pitch motion [0123]
f.sub.2 (t) frequency of heave motion [0124] h(t) heave [0125] HP
horizontal plane [0126] r(t) rotating radius [0127] t time [0128]
.alpha.(t) pitch angle [0129] .DELTA..sub.P(t) phase difference
* * * * *