U.S. patent application number 09/766851 was filed with the patent office on 2001-12-27 for automotive vehicle steering control device.
Invention is credited to Nishida, Minoru, Nishiwaki, Takeshi.
Application Number | 20010054519 09/766851 |
Document ID | / |
Family ID | 18691856 |
Filed Date | 2001-12-27 |
United States Patent
Application |
20010054519 |
Kind Code |
A1 |
Nishiwaki, Takeshi ; et
al. |
December 27, 2001 |
Automotive vehicle steering control device
Abstract
No automatic steering system is currently available, which has a
drive device commonly used with a power steering device and which
does not hinder the emergency escaping operation conducted by a
driver. An image sensor for detecting a positional relationship
between a subject automotive vehicle and an automotive vehicle
lane, a target steering quantity calculating process for obtaining
a target steering quantity A required for the automotive vehicle to
run along the automotive vehicle lane based on the positional
relationship, a torque sensor for detecting a manual steering force
with which a driver operates a steering handle, a target steering
quantity changing process for outputting a target steering quantity
B by changing the target steering quantity A based on the manual
steering force thus detected, a steering angle sensor for detecting
an actual steering quantity, and an automatic steering force
calculating process for obtaining an automatic steering force
required to make the target steering quantity B and the actual
steering quantity coincident with each other are provided. Even
during the automatic steering, steering can be carried out based on
the driver's intention.
Inventors: |
Nishiwaki, Takeshi; (Tokyo,
JP) ; Nishida, Minoru; (Tokyo, JP) |
Correspondence
Address: |
SUGHRUE, MION, ZINN, MACPEAK & SEAS
2100 Pennsylvania Avenue, N. W.
Washington
DC
20037
US
|
Family ID: |
18691856 |
Appl. No.: |
09/766851 |
Filed: |
January 23, 2001 |
Current U.S.
Class: |
180/167 ;
180/446 |
Current CPC
Class: |
B62D 1/286 20130101 |
Class at
Publication: |
180/167 ;
180/446 |
International
Class: |
B62D 006/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 27, 2000 |
JP |
2000-192772 |
Claims
What is claimed is:
1. An automotive vehicle steering control device comprising:
positional relationship detecting means for detecting a positional
relationship between a subject automotive vehicle and an automotive
vehicle lane; target steering quantity calculating means for
obtaining a first target steering quantity, required for the
automotive vehicle to run along the automotive vehicle lane, based
on the positional relationship; manual steering force detecting
means for detecting a manual steering force with which a driver
operates a steering handle; target steering quantity changing means
for outputting a second target steering quantity by changing the
first target steering quantity based on the manual steering force
thus detected; actual steering quantity detecting means for
detecting an actual steering quantity; and automatic steering force
calculating means for obtaining an automatic steering force
required to make the second target steering quantity and the actual
steering quantity coincident with each other.
2. An automotive vehicle steering control device comprising:
positional relationship detecting means for detecting a positional
relationship between a subject automotive vehicle and an automotive
vehicle lane; target steering quantity calculating means for
obtaining a target steering quantity, required for the automotive
vehicle to run along the automotive vehicle lane, based on the
positional relationship; manual steering force detecting means for
detecting a manual steering force with which a driver operates a
steering handle; actual steering quantity detecting means for
detecting an actual steering quantity; automatic steering force
calculating means for obtaining an automatic steering force
required to make the target steering quantity and the actual
steering quantity coincident with each other; and manual steering
assisting means for superimposing the manual steering force thus
detected and the automatic steering force thus obtained to each
other.
3. The automotive vehicle steering control device as claimed in
claim 2, further comprising: target steering quantity changing
means for outputting a second target steering quantity by changing
the target steering quantity based on the manual steering force
thus detected, wherein the automatic steering force calculating
means obtains the automatic steering force required to make the
second target steering quantity and the actual steering quantity
coincident with each other.
4. The automotive vehicle steering control device as claimed in
claim 2, further comprising: emergency escaping operation judging
means for judging a driver's emergency escaping motion if the
manual steering force detected by the manual steering force
detecting means exceeds a threshold value preliminarily set for the
manual steering force.
5. The automotive vehicle steering control device as claimed in
claim 4, further comprising: automatic steering force holding means
for constantly holding the automatic steering force obtained by the
automatic steering force calculating means if a notification
indicative of the driver's emergency escaping motion is given from
the emergency escaping operation judging means.
6. An automotive vehicle steering control device comprising:
positional relationship detecting means for detecting a positional
relationship between a subject automotive vehicle and an automotive
vehicle lane; target steering quantity calculating means for
obtaining a first target steering quantity, required for the
automotive vehicle to run along the automotive vehicle lane, based
on the positional relationship; automotive vehicle speed detecting
means for detecting an automotive vehicle speed of the subject
automotive vehicle: manual steering force detecting means for
detecting a manual steering force with which a driver operates a
steering handle; target steering quantity changing means for
outputting a second target steering quantity by changing the first
target steering quantity based on the automotive vehicle speed and
manual steering force thus detected; actual steering quantity
detecting means for detecting an actual steering quantity;
automatic steering force calculating means for obtaining an
automatic steering force required to make the second target
steering quantity and the actual steering quantity coincident with
each other; and manual steering assisting means for superimposing
the manual steering force thus detected and the automatic steering
force thus obtained to each other.
7. The automotive vehicle steering control device as claimed in
claim 6, further comprising: emergency escaping operation judging
means for judging a driver's emergency escaping motion if the
manual steering force detected by the manual steering force
detecting means exceeds a threshold value that is set based on
either one of the automotive vehicle speed detected by the
automotive vehicle speed detecting means and the actual steering
quantity detected by the actual steering quantity detecting
means.
8. The automotive vehicle steering control device as claimed in
claim 7, further comprising: automatic steering force gradually
decreasing means for gradually decreasing the automatic steering
force obtained by the automatic steering force calculating means if
a notification indicative of the driver's emergency escaping motion
is given from the emergency escaping operation judging means.
9. The automotive vehicle steering control device as claimed in
claim 3, further comprising: emergency escaping operation judging
means for judging a driver's emergency escaping motion if the
manual steering force detected by the manual steering force
detecting means exceeds a threshold value preliminarily set for the
manual steering force.
10. The automotive vehicle steering control device as claimed in
claim 9, further comprising: automatic steering force holding means
for constantly holding the automatic steering force obtained by the
automatic steering force calculating means if a notification
indicative of the driver's emergency escaping motion is given from
the emergency escaping operation judging means.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to an automotive vehicle
steering control device, which modifies a target steering quantity
depending on a manual steering force by the driver's operation, to
conduct the steering based on the driver's intention even under an
automatic steering control.
[0003] 2. Description of the Related Art
[0004] Various attempts have been made to superimpose the automatic
steering operation and the driver's steering operation to improve a
so-called automatic vehicle steering system which allows at least
some part of the steering operation to be automated during running
of the automotive vehicle.
[0005] Japanese Patent Application Laid-open No. 9-128699 discloses
an automotive vehicle steering angle correcting device, which is
provided with a drive device between a steering wheel grip portion
that is operated by a driver and a directing device, and which
generates such a drive output as to obtain a steering quantity
required for maintaining a vehicle running lane, thereby enabling
the driver's over-ride under the automatic steering control.
[0006] Japanese Patent Application Laid-open No. 9-221054 discloses
an automotive vehicle steering device in which an actuator for
driving a directing device to follow the vehicle running lane is
provided to conduct the lane maintaining control. The steering
device serves to increase or decrease a torque generated between
the directing device and the steering operated by a driver
depending on a difference between an angle of the directing device
and an angle of the steering operated by the driver, inform the
driver of the angular difference between the target steering angle
and the angle of the steering operated by the driver, and provide a
function to adjust the running course in the lane depending on the
difference. This permits the driver to conduct the over-ride with a
natural feeling.
[0007] Japanese Patent Application Laid-open Nos. 9-240502,
9-142327, 6-336170, and so on disclose an automotive vehicle
steering device, which detects the driver's over-ride based on the
magnitude of the driver's steering force, the quantity of change in
the steering force, the steering speed and so on, and automatically
switch over to the manual driving mode when the driver's over-ride
is conducted during the automatic driving mode.
[0008] The automotive vehicle steering devices, which are designed
to permit the driver's over-ride as mentioned above, makes it
possible to conduct the emergence escaping operation when a danger
is judged by the driver, for instance, when an obstructive object
on the lane is found during running. Under the current technology,
it is, however, difficult to conduct the emergency escaping
operation automatically and surely, and therefore, such a system is
desirable where man can drive the automotive vehicle with
initiative at least when the emergency escape is conducted.
[0009] Further, in a system which permits the driver to switch the
driving initiative from the automatic steering to the driver at the
time of the emergency escaping operation as mentioned above, the
switching of the driving initiative is carried out concurrently
when the driver performs the emergency escaping operation.
Therefore, it is desirable that the torque applied for the purpose
of conducting the automatic steering at the time of the switching
of the initiative does not hinder the driver's operation.
[0010] More specifically, it is desirable that means provided to
conduct the automatic steering, such as a steering actuator,
neither acts in contradiction to the driver's operation nor
adversely affects the driver's feeling at the time of the emergency
escaping operation, for example, abruptly changes the driver's
steering torque, to hinder or erroneously conduct the emergency
escaping operation.
[0011] In view of this, the automotive vehicle steering angle
correcting device disclosed in the Japanese Patent Application
Laid-open No. 9-128699 or the automotive vehicle steering device
disclosed in Japanese Patent Application Laid-open No. 9-221054 can
switch over to the manual steering with the operation torque
maintained at the time when the driver carries out the emergency
escaping operation. Accordingly, these devices do not adversely
affects the driver's feeling at the time of the emergency escaping
operation and do not hinder the emergency escaping operation. That
is, these system (the automotive vehicle steering angle correcting
device and the automotive vehicle steering device) are desirable
forms that take into account such an essential factor that the
emergency escaping operation be performed by the driver.
[0012] Besides, in general, a power steering device is widely used
for an automotive vehicle to reduce the driver's operation force
required to operate a directing device. The power steering drive is
designed to actuate the directing device in the driver's operating
direction depending on the driver's operation torque.
[0013] Recently, as the power steering device, a motor-driven power
steering device is widely used, which has a torque sensor for
detecting the driver's operation force, an electrically-driven
motor for actuating the directing device, and a controller for
determining and outputting a driving output and a direction of the
electrically-driven motor depending on the driver's operation force
detected by the torque sensor.
[0014] The motor-driven power steering device provides sufficient
output power enabling a large angle steering (turning the handle
with the vehicle not moving), and since the power required to steer
and direct the running vehicle is generally smaller than the power
required for the large angle steering, it can be used as an
actuator of the automatic steering system. Assuming that the
automatic steering system is incorporated in the automotive vehicle
equipped with the motor-driven power steering device, the common
use of the electrically-driven motor and the controller makes it
possible to realize the automatic steering system with reduced
cost, in comparison to a case where the separate
electrically-driven motors and the separate controllers are
provided.
[0015] However, each of the automotive vehicle steering angle
correcting device disclosed in the Japanese Patent Application
Laid-open No. 9-128699 and the automotive vehicle steering device
disclosed in Japanese Patent Application Laid-open No. 9-221054 is
designed such that the driving device is provided between the
steering wheel grip portion operated by the driver and the
directing device, and therefore, the electrically-driven motor of
the power steering device, which directly drives the directing
device, can not be used commonly as the driving device. For this
reason, even in a case where the automatic steering system is
incorporated in the vehicle having the motor-driven power steering
device, it is necessary to install a dedicated electrically-driven
motor and a dedicated controller, resulting in increased cost.
[0016] On the other hand, the systems which switch the driving
initiative from the automatic steering to the driver in the case of
emergency as disclosed such as in the Japanese Patent Application
Laid-open Nos. 9-240502 and 9-142327 are each designed to drive the
directing device, and therefore it is possible to commonly use the
electrically-driven motor and controller of the motor-driven power
steering device and thus realize the automatic steering system with
reduced cost.
[0017] Although these systems are designed to switch the driving
initiative from the automatic steering to the driver in the case of
emergency, each of these systems interrupts the automatic steering
control at the time of the switching, and therefore inevitably
encounters the abrupt change of the operation torque. For these
reasons, these systems adversely affect the driver's feeling at the
time of the emergency escaping operation and hinder or erroneously
conduct the emergency escaping operation. Accordingly, these
devices cannot be considered as desirable system forms that take
into account such an essential factor that the emergency escaping
operation be performed by the driver.
[0018] As discussed above, no automotive vehicle steering control
device (automatic steering system) is currently available, which
has a drive device commonly used with a power steering device and
which does not hinder the emergency escaping operation conducted by
a driver.
SUMMARY OF THE INVENTION
[0019] The present invention was made in order to solve the
aforementioned problems. An object of the present invention is to
provide an automotive vehicle steering control device which has a
drive device commonly used by a power steering device and which
does not hinder the emergency escaping operation conducted by a
driver.
[0020] An automotive vehicle steering control device according to a
first aspect of the present invention includes: positional
relationship detecting means for detecting a positional
relationship between a subject automotive vehicle and an automotive
vehicle lane; target steering quantity calculating means for
obtaining a first-target steering quantity, required for the
automotive vehicle to run along the automotive vehicle lane, based
on the positional relationship; manual steering force detecting
means for detecting a manual steering force with which a driver
operates a steering handle; target steering quantity changing means
for outputting a second target steering quantity by changing the
first target steering quantity based on the manual steering force
thus detected; actual steering quantity detecting means for
detecting an actual steering quantity; and automatic steering force
calculating means for obtaining an automatic steering force
required to make the second target steering quantity and the actual
steering quantity coincident with each other.
[0021] An automotive vehicle steering control device according to a
second aspect of the present invention includes: positional
relationship detecting means for detecting a positional
relationship between a subject automotive vehicle and an automotive
vehicle lane; target steering quantity calculating means for
obtaining a target steering quantity, required for the automotive
vehicle to run along the automotive vehicle lane, based on the
positional relationship; manual steering force detecting means for
detecting a manual steering force with which a driver operates a
steering handle; actual steering quantity detecting means for
detecting an actual steering quantity; automatic steering force
calculating means for obtaining an automatic steering force
required to make the target steering quantity and the actual
steering quantity coincident with each other; and manual steering
assisting means for superimposing the manual steering force thus
detected and the automatic steering force thus obtained to each
other.
[0022] An automotive vehicle steering control device according to a
third aspect of the present invention, further includes: target
steering quantity changing means for outputting a second target
steering quantity by changing the target steering quantity based on
the manual steering force thus detected, wherein the automatic
steering force calculating means obtains the automatic steering
force required to make the second target steering quantity and the
actual steering quantity coincident with each other.
[0023] An automotive vehicle steering control device according to a
fourth and a ninth aspects of the present invention, further
includes: emergency escaping operation judging means for judging a
driver's emergency escaping motion if the manual steering force
detected by the manual steering force detecting means exceeds a
threshold value preliminarily set for the manual steering
force.
[0024] An automotive vehicle steering control device according to a
fifth and a tenth aspects of the present invention, further
includes: automatic steering force holding means for constantly
holding the automatic steering force obtained by the automatic
steering force calculating means if a notification indicative of
the driver s emergency escaping motion is given from the emergency
escaping operation judging means.
[0025] An automotive vehicle steering control device according to a
sixth aspect of the present invention includes: positional
relationship detecting means for detecting a positional
relationship between a subject automotive vehicle and an automotive
vehicle lane; target steering quantity calculating means for
obtaining a first target steering quantity, required for the
automotive vehicle to run along the automotive vehicle lane, based
on the positional relationship; automotive vehicle speed detecting
means for detecting an automotive vehicle speed of the subject
automotive vehicle: manual steering force detecting means for
detecting a manual steering force with which a driver operates a
steering handle; target steering quantity changing means for
outputting a second target steering quantity by changing the first
target steering quantity based on the automotive Vehicle speed and
manual steering force thus detected; actual steering quantity
detecting means for detecting an actual steering quantity;
automatic steering force calculating means for obtaining an
automatic steering force required to make the second target
steering quantity and the actual steering quantity coincident with
each other; and manual steering assisting means for superimposing
the manual steering force thus detected and the automatic steering
force thus obtained to each other.
[0026] An automotive vehicle steering control device according to a
seventh aspect of the present invention, further includes:
emergency escaping operation judging means for judging a driver's
emergency escaping motion if the manual steering force detected by
the manual steering force detecting means exceeds a threshold value
that is set based on either one of the automotive vehicle speed
detected by the automotive vehicle speed detecting means and the
actual steering quantity detected by the actual steering quantity
detecting means.
[0027] An automotive vehicle steering control device according to
an eighth aspect of the present invention, further includes:
automatic steering force gradually decreasing means for gradually
decreasing the automatic steering force obtained by the automatic
steering force calculating means if a notification indicative of
the emergency escaping motion is given from the emergency escaping
operation judging means.
BRIEF DESCRIPTION OF THE DRAWINGS
[0028] FIG. 1 shows an entire arrangement of an automotive vehicle
steering control device according to a first embodiment of the
present invention.
[0029] FIG. 2 is a block diagram showing an arrangement of the
automotive vehicle steering control device according to the first
embodiment of the present invention.
[0030] FIG. 3 shows the operation of a target steering quantity
changing process in a processing device of the automotive vehicle
steering control device according to the first embodiment of the
present invention.
[0031] FIG. 4 shows the operation of an automatic steering force
calculating process in the processing device of the automotive
vehicle steering control device according to the first embodiment
of the present invention.
[0032] FIG. 5 shows the operation of an emergency escaping motion
judging process in the processing device of the automotive vehicle
steering control device according to the first embodiment of the
present invention.
[0033] FIG. 6 shows the operation of an automatic steering force
holding process in the processing device of the automotive vehicle
steering control device according to the first embodiment of the
present invention.
[0034] FIG. 7 shows the operation of a manual steering assisting
process in the processing device of the automotive vehicle steering
control device according to the first embodiment of the present
invention.
[0035] FIG. 8 is a block diagram showing an arrangement of an
automotive vehicle steering control device according to the second
embodiment of the present invention.
[0036] FIG. 9 shows the operation of a target steering quantity
changing process in a processing device of the automotive vehicle
steering control device according to the second embodiment of the
present invention.
[0037] FIG. 10 shows the operation of the coefficient setting
process section of the target steering quantity changing process in
the processing device of the automotive vehicle steering control
device according to the second embodiment of the present
invention.
[0038] FIG. 11 shows the operation of an emergency escaping motion
judging process in the processing device of the automotive vehicle
steering control device according to the second embodiment of the
present invention.
[0039] FIG. 12 shows the operation of the emergency escaping motion
judging threshold value setting process of the emergency escaping
motion judging process in the processing device of the automotive
vehicle steering control device according to the second embodiment
of the present invention.
[0040] FIG. 13 shows the operation of an automatic steering force
gradually decreasing process in the processing device of the
automotive vehicle steering control device according to the second
embodiment of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0041] First Embodiment
[0042] An automotive vehicle steering control device according to a
first embodiment of the present invention will be described with
reference to the drawings. FIG. 1 shows an entire arrangement of
the automotive vehicle steering control device according to the
first embodiment of the present invention. FIG. 2 is a block
diagram showing an arrangement of a processing device of the
automotive vehicle steering control device according to the first
embodiment of the present invention. Note that, in respective
drawings, the same numerals represent the same or corresponding
parts.
[0043] In FIG. 1, a reference numeral 10 designates an image sensor
(positional relationship detecting means) provided at a front
portion or the like of an automotive vehicle, a reference numeral
20 designates a steering angle sensor (actual steering quantity
detecting means) which detects an actual steering quantity (a
steering angle or a steering position), a reference numeral 30
designates a torque sensor (manual steering force detecting means)
which detects a manual steering force (an operation force or an
operation torque) with which a driver operates a steering handle, a
reference numeral 40 designates a processing device, which is a
computer system, having a CPU, a memory or the like, a reference
numeral 50 designates a power steering motor, and a reference
numeral 60 designates an automotive vehicle speed sensor
(automotive vehicle speed detecting means) built in an information
panel meter. As the positional relationship detecting means, for
example, a magnetic nail sensor may be used to recognize a running
lane in place of the image sensor 10, or a radio wave marker or the
like may be used.
[0044] In FIG. 2, the processing device 40 includes a target
steering quantity calculating process (target steering quantity
calculating means) 41 which obtains a target steering quantity (a
steering angle or a steering position) A required for the
automotive vehicle to run along a vehicle lane partitioning line, a
target steering quantity changing process (target steering quantity
changing means) 42 which changes the target steering quantity B in
accordance with a detected manual steering force, an automatic
steering force calculating process (automatic steering force
calculating means) 43, which obtains an automatic steering force (a
steering force or a steering torque) A that is calculated from a
difference between the actual steering quantity and the target
steering quantity B, an n-ordered differential value of the
difference, an integral value thereof, a combination of any two of
these, or all of these, and that is required to make the actual
steering quantity and the target steering quantity B coincident
with each other, an emergency escaping motion judging process
(emergency escaping motion judging means) 44 which detects an
emergency escaping operation of a driver, an automatic steering
force holding process (automatic steering force holding means) 45
which holds the automatic steering force B constant if it is judged
that the emergency escaping operation is being conducted by the
driver, and a manual steering assisting process (manual steering
assisting means) 46 which superimpose the steering force depending
on the manual steering force with the automatic steering force B to
output to the power steering motor 50.
[0045] Next, the operation of the automotive vehicle steering
control device according to the first embodiment will be described
with reference to the drawings.
[0046] FIG. 3 shows the operation of a target steering quantity
changing process in the processing device of the automotive vehicle
steering control device according to the first embodiment of the
present invention. In FIG. 3, a reference character Km denotes a
coefficient which is set in conformity with a kinematic
characteristic of the automotive vehicle.
[0047] FIG. 4 shows the operation of an automatic steering force
calculating process in the processing device of the automotive
vehicle steering control device according to the first embodiment
of the present invention. In FIG. 4, a reference character Kp
denotes a steering angle feed-back control gain and a reference
character Kd denotes a steering angle speed feed-back control
gain.
[0048] FIG. 5 shows the operation of an emergency escaping motion
judging process in the processing device of the automotive vehicle
steering control device according to the first embodiment of the
present invention.
[0049] FIG. 6 shows the operation of an automatic steering force
holding process in the processing device of the automotive vehicle
steering control device according to the first embodiment of the
present invention.
[0050] FIG. 7 shows the operation of a manual steering assisting
process in the processing device of the automotive vehicle steering
control device according to the first embodiment of the present
invention. In FIG. 7, a reference character Ka denotes a steering
operation assist gain.
[0051] First of all, the target steering quantity calculating
process 41 in the processing device 40 calculates a steering angle,
required for an automotive vehicle to run along a vehicle lane,
based on a positional relationship between the subject automotive
vehicle and the vehicle lane, which is recognized by detecting a
position, shape or the like of an vehicle lane partitioning line,
and outputs the thus calculated steering angle as the target
steering quantity A.
[0052] Next, as shown in FIG. 3, the target steering quantity
changing process 42 in the processing device 40 adds, to the target
steering quantity A, a value obtained by multiplying the
coefficient Km by a value of the manual steering force inputted
through the torque sensor 30 to the processing device 40, and
outputs the result as the target steering quantity B.
[0053] Next, as shown in FIG. 4, the automatic steering force
calculating process 43 in the processing device 40 sets, as the
target steering speed, a value obtained by multiplying the gain Kp
by a difference between the actual steering quantity from the
steering angle sensor 20 and the target steering quantity B, and
outputs as the automatic steering force A, a value obtained by
multiplying the gain Kd by a difference between a differential
value of the actual steering quantity and a differential value of
the target steering speed. This process is a feed-back control
having the speed feed-back in the minus loop.
[0054] Next, as shown in FIG. 5, the emergency escaping motion
judging process 44 in the process device 40 notifies the automatic
steering force holding process 45 of the driver's emergency
escaping operation if a value of the manual steering force inputted
through the torque sensor 30 to the processing device 40 is larger
than a threshold value that is set so as to be the same level as a
force generated when the driver intentionally operates the steering
handle.
[0055] Next, as shown in FIG. 6, the automatic steering force
holding process 45 in the processing device 40 outputs the
automatic steering force A per se as the automatic steering force B
if the driver's emergency escaping operation is not notified by the
emergency escaping motion judging process 44. On the other hand, if
the driver's emergency escaping operation is notified, the
automatic steering force holding process 45 holds the value of the
automatic steering force A at the time of the start of the
notification, and outputs the thus held value as the automatic
steering force B.
[0056] Subsequently, as shown in FIG. 7, the manual steering
assisting process 46 in the processing device 40 multiplies the
gain Ka by the value of the manual steering force inputted through
the torque sensor 30 to the processing device 40, and adds the
result to the automatic steering force B to obtain and output a
drive output to the power steering motor 50.
[0057] That is, since the automotive vehicle steering control
device according to the first embodiment of the present invention
is provided with the target steering quantity changing process 42
that changes the target steering quantity A depending on the manual
steering force of the driver's operation, it is possible to conduct
the steering based on the driver's intention even under the
automatic steering control.
[0058] Since the manual steering assisting process 46 is provided,
which superimposes and outputs a steering force depending on the
manual steering force of the driver's operation with the automatic
steering force A or B, it is possible to conduct the steering based
on the driver's intention even under the automatic steering
control.
[0059] Note, however, that the mere provision of the manual
steering assisting process 46 will cause the change in actual
steering quantity by the superimposed output of the automatic
steering force A with the steering force depending on the manual
steering force, and the automatic steering force A will be
increased or decreased in order to correct this change. This
increase or decrease in the automatic steering force A will act in
a direction so as to correct a deviation of the actual steering
quantity from the manual steering force and thus conflict with the
manual steering force. For this reason, both the manual steering
assisting process 46 and the target steering quantity changing
process 42 are provided to adjust the target steering quantity A
depending on the manual steering force in order to eliminate the
conflict. Therefore, the automatic steering can be prevented from
conflicting with the manual steering.
[0060] The provision of the manual steering assisting process 46
will cause the change in actual steering quantity by the
superimposed output of the automatic steering force A with the
steering force depending on the manual steering force, and the
target steering quantity calculating process 41, which obtains the
target steering quantity A to change the automotive vehicle posture
depending on the change in the actual steering quantity, will
increase or decrease the target steering quantity A in order for
the automotive vehicle to run along the vehicle lane partitioning
line by correcting the change of the automotive vehicle posture.
Since the increase or decrease of the target steering quantity A
will serve to correct the automotive vehicle posture changed by the
manual steering force to return to the original posture, and thus
will serve to hinder the manual steering and to conflict with the
manual steering force. For this reason, the automatic steering
force holding process 45 is provided in order to hold the automatic
steering force B constant when the steering handle is largely
operated to escape from the emergency. Accordingly, no conflict
motion occurs, and there is no case where the driver's emergency
escaping operation is hindered. Further, since the automatic
steering force B is kept constant, the abrupt change in the
operation force never occurs. Therefore, there is not case that the
steering feeling is adversely affected to erroneously conduct the
driver's emergency escaping operation.
[0061] Since the emergency escaping motion judging process 44 is
provided, which detects the driver's emergency escaping operation
based on the detected value of the torque sensor 30 that has been
already used in the system, it is possible to detect the emergency
escaping operation without providing a new detecting device,
thereby making it possible to suppress the cost increase.
[0062] Second Embodiment
[0063] An automotive vehicle steering control device according to a
second embodiment of the present invention will be described with
reference to the drawings. FIG. 8 is a block diagram showing an
arrangement of an automotive vehicle steering control device
according to the second embodiment of the present invention. The
entire arrangement of the second embodiment is similar to that of
the first embodiment.
[0064] In FIG. 8, the processing device 40A includes, in place of
the automatic steering force holding process 45, an automatic
steering force gradually decreasing process (automatic steering
force gradually decreasing means) 47 which gradually decreases the
automatic steering force B when it is judged that the emergency
escaping operation is conducted by the driver.
[0065] Next, the operation of the automotive vehicle steering
control device according to the second embodiment will be described
with reference to the drawings.
[0066] FIG. 9 shows the operation of a target steering quantity
changing process in the processing device of the automotive vehicle
steering control device according to the second embodiment of the
present invention. In FIG. 9, a reference character Km denotes a
coefficient which is set in conformity with a kinematic
characteristic of the automotive vehicle. A reference numeral 42a
denotes a coefficient setting process section.
[0067] FIG. 10 shows the operation of the coefficient setting
process section of the target steering quantity changing process in
the processing device of the automotive vehicle steering control
device according to the second embodiment of the present
invention.
[0068] FIG. 11 shows the operation of an emergency escaping motion
judging process in the processing device of the automotive vehicle
steering control device according to the second embodiment of the
present invention. In FIG. 11, a reference numeral 44a denotes an
emergency escaping motion judging threshold value setting process,
and a reference numeral 44b denotes a comparator.
[0069] FIG. 12 shows the operation of the emergency escaping motion
judging threshold value setting process of the emergency escaping
motion judging process in the processing device of the automotive
vehicle steering control device according to the second embodiment
of the present invention.
[0070] FIG. 13 shows the operation of an automatic steering force
gradually decreasing process in the processing device of the
automotive vehicle steering control device according to the second
embodiment of the present invention.
[0071] The second embodiment differs from the first embodiment in
operation of the target steering quantity process 42 and the
emergency escaping motion judging process 44, and in that the
automatic steering force holding process 45 is replaced with the
automatic steering force gradually decreasing process 47. The
operation associated with different points from the first
embodiment will be described in the following paragraphs.
[0072] The processing device 40A differs from the processing device
40 of the first embodiment in that in the target steering quantity
process 42, as shown in FIG. 9, the coefficient setting process
section 42a is provided to variably change the coefficient
depending on the automotive vehicle speed detected by the
automotive vehicle speed sensor 60. As shown in FIG. 10, the
coefficient setting process section 42a is designed to set the
coefficient Km, which is to be multiplied to the value of the
manual steering force inputted through the torque sensor 30, to be
large as the automotive vehicle speed is low, and low as the
automotive vehicle speed is high.
[0073] The processing device 40A differs from the processing device
40 of the first embodiment in that, as shown in FIG. 11 in the
emergency escaping motion judging process 44, the emergency
escaping motion judging threshold value setting process 44a is
provided, which variably changes the judging threshold value
depending on the automotive vehicle speed and the actual steering
quantity. As shown in FIG. 12, the emergency escaping motion
judging threshold value setting process 44a sets the threshold
value for judgement of the emergency escaping motion to be large as
the automotive vehicle speed is low, small as the automotive
vehicle speed is high, large as the actual steering quantity is
large and small as the actual steering quantity is small.
[0074] As shown in FIG. 13, the automatic steering force gradually
decreasing process 47 in the processing device 40A outputs the
automatic steering force A per se as the automatic steering force B
if the driver's emergency escaping motion is not notified by the
emergency escaping motion judging process 44. If the emergency
escaping motion is notified, the automatic steering force gradually
decreasing process 47 outputs, as the automatic steering force B, a
value that is obtained by gradually decreasing the automatic
steering force A at the time of the start of the notification
depending on the elapsed time period from the time point of the
start of the notification.
[0075] That is, since the automotive vehicle steering control
device according to the second embodiment is provided in place of
the automatic steering force holding process 45 holding the
automatic steering force constant, with the automatic steering
force gradually decreasing process 47 which gradually decreases the
automatic steering force, it is possible to suppress the effect of
the automatic steering force to the driver while maintaining the
function of avoiding the abrupt change of the operation force as
explained in the first embodiment.
[0076] In order to detect and judge the driver's emergency escaping
operation based on the manual steering force detected by the torque
sensor 30, the emergency escaping motion judging process 44 is
provided which takes into account the automotive vehicle speed
detected by the automotive vehicle speed sensor 60 and the actual
steering quantity detected by the steering angle sensor 20, and
therefore the accuracy of the judgement can be enhanced.
[0077] Since the target steering quantity changing process 42 is
provided to adjust the relationship between the manual steering
force and the change of the target steering quantity depending on
the automotive vehicle speed, it is possible to conduct the
emergency escaping operation with a more natural feeling.
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