U.S. patent application number 11/809032 was filed with the patent office on 2007-10-11 for turning motion control system for vehicle.
This patent application is currently assigned to HONDA MOTOR CO., LTD.. Invention is credited to Nobuyuki Imaizumi, Yoshihiro Iwagawa, Hironobu Kiryu, Susumu Ohta, Kazunari Okada, Kazuya Sakurai, Masakazu Shiraishi, Tomoaki Sugano, Toshio Yahagi.
Application Number | 20070239334 11/809032 |
Document ID | / |
Family ID | 34722873 |
Filed Date | 2007-10-11 |
United States Patent
Application |
20070239334 |
Kind Code |
A1 |
Imaizumi; Nobuyuki ; et
al. |
October 11, 2007 |
Turning motion control system for vehicle
Abstract
A turning motion control system for a vehicle includes an
actuator, and an actuator control device for controlling the
actuator so that an actual turning motion state of the vehicle
becomes close to a target turning motion state. The actuator
control device is designed so that its control-permitted state and
its control-stopped state can be switched from one to another
through a switching device operated by a driver. When an
air-pressure decreased state detecting device has detected an
air-pressure decreased state, the actuator control device carries
out the control of the operation of the actuator, irrespective of a
switching mode of the switching device. Thus, even if an
air-pressure decrease or an abnormality is generated in any of
wheels in a state in which the turning motion control by the
actuator has been stopped, the stability of the vehicle can be
ensured.
Inventors: |
Imaizumi; Nobuyuki;
(Wako-shi, JP) ; Iwagawa; Yoshihiro; (Wako-shi,
JP) ; Ohta; Susumu; (Wako-shi, JP) ; Okada;
Kazunari; (Wako-shi, JP) ; Kiryu; Hironobu;
(Wako-shi, JP) ; Sakurai; Kazuya; (Wako-shi,
JP) ; Shiraishi; Masakazu; (Wako-shi, JP) ;
Sugano; Tomoaki; (Wako-shi, JP) ; Yahagi; Toshio;
(Wako-shi, JP) |
Correspondence
Address: |
HAMRE, SCHUMANN, MUELLER & LARSON, P.C.
P.O. BOX 2902
MINNEAPOLIS
MN
55402-0902
US
|
Assignee: |
HONDA MOTOR CO., LTD.
Tokyo
JP
|
Family ID: |
34722873 |
Appl. No.: |
11/809032 |
Filed: |
May 31, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10991652 |
Nov 8, 2004 |
7260459 |
|
|
11809032 |
May 31, 2007 |
|
|
|
Current U.S.
Class: |
701/41 |
Current CPC
Class: |
B60T 8/1755 20130101;
B60T 2201/16 20130101 |
Class at
Publication: |
701/041 |
International
Class: |
B62D 6/00 20060101
B62D006/00 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 27, 2003 |
JP |
2003-397825 |
Claims
1. (canceled)
2. A turning motion control system for a vehicle, comprising: a
target turning motion state determining means for determining a
target turning motion state of the vehicle; a turning motion state
detecting means for detecting an actual turning motion of the
vehicle; an actuator control means for controlling an actuator so
that the actual turning motion state of the vehicle detected by the
turning motion state detecting means becomes close to the target
turning motion state determined by the target turning motion state
determining means; and a switching means adapted to switch over a
control-permitted state and a control-stopped state of the actuator
upon operation by a driver, wherein the system further comprises:
wheel speed sensors for detecting wheel speeds of a plurality of
wheels, respectively; and a wheel abnormal state detecting means
for detecting an abnormal state of any of the wheels, based on
comparison of values detected by the wheel speed sensors with one
another, and wherein the actuator control means is adapted to carry
out the control of the operation of the actuator, irrespective of
the switching mode of the switching means, when the air-pressure
decreased state detecting means has detected the air-pressure
decreased state.
Description
RELATED APPLICATION DATA
[0001] This application is a Division of application Ser. No.
10/991,652, filed Nov. 8, 2004, which application is incorporated
herein by reference. The Japanese priority application No.
2003-397825 upon which the present application is based is hereby
incorporated in its entirety herein by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a turning motion control
system for a vehicle, comprising: a target turning motion state
determining means for determining a target turning motion state of
the vehicle; a turning motion state detecting means for detecting
an actual turning motion of the vehicle; an actuator control means
for controlling an actuator so that the actual turning motion state
of the vehicle detected by the turning motion state detecting means
becomes close to the target turning motion state determined by the
target turning motion state determining means; and a switching
means adapted to switch over a control-permitted state and a
control-stopped state of the actuator upon operation by a
driver.
[0004] 2. Description of the Related Art
[0005] Such a turning motion control system is already known, for
example, from Japanese Patent Publication No. 3214824. There is
another conventional turning motion control system, in which
turning motion control by operation of an actuator is turned on and
off by a vehicle driver's intention during circuit traveling or for
a convenience of use.
[0006] However, in a state in which the turning motion control by
the actuator has been stopped by the driver's intention, if an
air-pressure decreases in any of wheels or if any of the wheels is
fallen into an abnormal state, stability of the vehicle is
sometimes difficult to be secured when a sudden steering is
conducted.
SUMMARY OF THE INVENTION
[0007] Accordingly, it is an object of the present invention to
provide a turning motion control system for a vehicle, wherein
stability of the vehicle can be ensured even if an air-pressure
decrease or an abnormally is generated in any of wheels in a state
in which turning motion control by an actuator has been
stopped.
[0008] To achieve the above object, according to a first feature of
the present invention, there is provided a turning motion control
system for a vehicle, comprising: a target turning motion state
determining means for determining a target turning motion state of
the vehicle; a turning motion state detecting means for detecting
an actual turning motion of the vehicle; an actuator control means
for controlling an actuator so that the actual turning motion state
of the vehicle detected by the turning motion state detecting means
becomes close to the target turning motion state determined by the
target turning motion state determining means; and a switching
means adapted to switch over a control-permitted state and a
control-stopped state of the actuator upon operation by a driver,
wherein the system further comprises an air-pressure decreased
state detecting means capable of detecting an air-pressure
decreased state of any of wheels, and wherein the actuator control
means is adapted to carry out the control of the operation of the
actuator, irrespective of the switching mode of the switching
means, when the air-pressure decreased state detecting means has
detected the air-pressure decreased state.
[0009] With the arrangement of the first feature, in a state in
which the driver has operated the switching means to stop the
turning motion control by the actuator, when the air-pressure
decreased state detecting means detects an air-pressure decreased
state, the actuator control means controls the actuator so that the
actual turning motion state of the vehicle becomes close to the
target turning motion state. Therefore, the stability of the
vehicle can be ensured.
[0010] According to a second feature of the present invention,
there is provided a turning motion control system for a vehicle,
comprising: a target turning motion state determining means for
determining a target turning motion state of the vehicle; a turning
motion state detecting means for detecting an actual turning motion
of the vehicle; an actuator control means for controlling an
actuator so that the actual turning motion state of the vehicle
detected by the turning motion state detecting means becomes close
to the target turning motion state determined by the target turning
motion state determining means; and a switching means adapted to
switch over a control-permitted state and a control-stopped state
of the actuator upon operation by a driver, wherein the system
further comprises: wheel speed sensors for detecting wheel speeds
of a plurality of wheels, respectively; and a wheel abnormal state
detecting means for detecting an abnormal state of any of the
wheels, based on comparison of values detected by the wheel speed
sensors with one another, and wherein the actuator control means is
adapted to carry out the control of the operation of the actuator,
irrespective of the switching mode of the switching means, when the
air-pressure decreased state detecting means has detected the
air-pressure decreased state.
[0011] With the arrangement of the second feature, in a state in
which the driver has operated the switching means to stop the
turning motion control by the actuator, when the wheel abnormal
state detecting means detects an abnormal state of any of the
wheels through comparison of the plurality of wheel speeds with one
another, the actuator control means controls the actuator so that
the actual turning motion state of the vehicle becomes close to the
target turning motion state. Therefore, the stability of the
vehicle can be ensured.
[0012] The above and other objects, features and advantages of the
invention will become apparent from the following description of
the preferred embodiment with reference to the accompanying
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1 is an illustration showing the entire arrangement of
a drive system and a control system of a vehicle.
[0014] FIG. 2 is a diagram of a liquid pressure circuit showing
arrangement of an actuator.
[0015] FIG. 3 is a diagram showing a portion of an instrument
panel.
[0016] FIG. 4 is a diagram showing arrangement of the control
system associated with turning motion control.
[0017] FIG. 5 is a flow chart showing a procedure of detecting an
abnormal state by a wheel abnormal state detecting means.
[0018] FIG. 6 is a flow chart showing a procedure of determining
whether or not turning motion control should be conducted.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0019] Referring first to FIG. 1, an output from a transmission T
connected in series to an engine E is transmitted to front left and
front right wheels WFL and WFR which are left end right driven
wheels of a front-engine front-wheel-drive (FF) vehicle V. Front
left and front right wheel brakes 5FL and 5FR are mounted on the
front wheels WFL and WFR. Rear left and rear right wheel brakes 5RL
and 5RR are mounted on rear left and rear right wheels WRL and WRR
which are left and right follower wheels.
[0020] A master cylinder M is of a tandem type and adapted to
output a braking liquid pressure in response to the operation of a
brake pedal P by a vehicle driver. The master cylinder M is
connected to the wheel brakes 5FL, 5FR, 5RL and 5RR through an
actuator 4 which is a braking liquid pressure control unit.
[0021] Referring to FIG. 2, the master cylinder M includes first
and second output ports 1A and 1B which generate braking liquid
pressures. The first output port 1A is connected to a first output
liquid pressure passage 3A, and the second output port 1B is
connected to a second output liquid pressure passage 3B. Both the
output liquid pressure passages 3A and 3B are connected to the
actuator 4.
[0022] The actuator 4 includes: a normally-opened type solenoid
valve 6FL, a check valve 7FL and a normally-closed type solenoid
valve 9FL, all of which correspond to the front left wheel brake
5FL; a normally-opened type solenoid valve 6RR, a check valve 7RR
and a normally-closed type solenoid valve 9RR all of which
correspond to the rear right wheel brake 5RR; a first reservoir 8A,
a first pump 10A, a first damper 13A, a first cut valve 17A, a
first suction valve 18A and a first one-way valve 19A, all of which
correspond to the front left wheel brake 5FL and the rear right
wheel brake 5RR; a normally-opened type solenoid valve 6FR, a check
valve 7FR and a normally-closed type solenoid valve 9FR, all of
which correspond to the front right wheel brake 5FR; a
normally-opened type solenoid valve 6RL, a check valve 7RL and a
normally-closed type solenoid valve 9RL, all of which correspond to
the rear left wheel brake 5RL; a second reservoir 8B, a second pump
10B, a second damper 13B, a second cut valve 17B, a second suction
valve 18B and a second one-way valve 19B, all of which correspond
to the front right wheel brake 5FR and the rear left wheel brake
5RL.
[0023] The first output liquid pressure passage 3A is connected to
a first liquid pressure passage 20A through the first cut valve 17A
which is a normally-opened type solenoid valve. The second output
liquid pressure passage 3B is connected to a second liquid pressure
passage 20B through the second cut valve 17B which is a
normally-opened type solenoid valve.
[0024] The first liquid pressure passage 20A is connected to the
front left wheel brake 5FL through the normally-opened type
solenoid valve 6FL, and to the rear right wheel brake 5RR through
the normally-opened type solenoid valve 6RR. The second liquid
pressure passage 20B is connected to the front right wheel brake
5FR through the normally-opened type solenoid valve 6FR, and to the
rear left wheel brake 5RL through the normally-opened type solenoid
valve 6RL. The check valves 7FL, 7FR, 7RL and 7RR are connected in
parallel to the normally-opened type solenoid valves 6FL, 6FR, 6RL
and 6RR, respectively.
[0025] The normally-closed type solenoid valves 9FL and 9RR are
mounted between the first reservoir 8A and the front left wheel
brake SFL as well as the rear right wheel brake 5RR, respectively.
The normally-closed type solenoid valves 9FR and 9RL are mounted
between the second reservoir 8B and the front right wheel brake 5FR
as well as the rear left wheel brake 5RL, respectively.
[0026] The first and second reservoirs 8A and 8B are connected to
intake sides of the first and second pumps 10A and 10B driven by an
electric motor 11 which is a common electric actuator through the
first and second one-way valves 19A and 19B adapted to permit the
flow of a braking liquid toward the pumps 10A and 10B. The first
and second liquid pressure passages 20A and 20B are connected
between the first and second pumps 10A and 10B and the one-way
valves 19A and 19B through the first and second suction valves 18A
and 18B which are normally-closed type solenoid valves, and to
discharge sides of the first and second pumps 10A and 10B through
the first and second dampers 13A and 13B.
[0027] In such an actuator 4, during usual braking in a state in
which the first and second cut valves 17A and 17B have been opened
and the first and second suction valves 18A and 18B haven been
closed, the normally-opened type solenoid valves 6FL to 6RR are
brought into a deexcited and opened state, and the normally-closed
type solenoid valves 9FL to 9RR are brought into a deexcited and
closed state; and a braking liquid pressure output from the first
output port 1A in the master cylinder M is applied to the front
left and rear right wheel brakes 5FL and 5RR through the
normally-opened type solenoid valves 6FL and 6RR. In addition, a
braking liquid pressure output from the second output port 1B in
the master cylinder M is applied to the front right and rear left
wheel brakes 5FR and 5RL through the normally-opened type solenoid
valves 6FR and 6RL.
[0028] When a wheel is about to be brought into a locked state
during the braking, one of the normally-opened type solenoid valves
6FL to 6RR corresponding to such a near-lock wheel is excited and
closed, and one of the normally-closed type solenoid valves 9FL to
9RR corresponding the near-lock wheel is excited and opened. Thus,
a portion of the braking liquid pressure for the near-lock wheel is
absorbed into the first reservoir 8A or the second reservoir 8B,
whereby the braking liquid pressure for the near-lock wheel is
reduced.
[0029] To maintain the braking liquid pressure constant, the
normally-opened type solenoid valves 6FL to 6RR are brought into an
excited and closed state, and the normally-closed type solenoid
valves 9FL to 9RR are brought into a deexcited and closed state.
Further, to increase the braking liquid pressure, the
normally-opened type solenoid valves 6FL to 6RR are brought into a
deexcited and opened state, and the normally-closed type solenoid
valves 9FL to 9RR are brought into a deexcited and closed
state.
[0030] By controlling the deexcitation and excitation of the
normally-opened type solenoid valves 6FL to 6RR and the
normally-closed type solenoid valves 9FL and 9RR in this manner,
the braking can be conducted with a good efficiency without locking
the wheels.
[0031] During an antilock brake control operation as described
above, the electric motor 11 is operated to rotate, and the first
and second pumps 10A and 10B are driven with the operation of the
electric motor 11. Therefore, the braking liquid absorbed into the
first and second reservoirs 8A and 8B is drawn into the first and
second pumps 10A and 10B, and then returned through the first and
second dampers 13A and 13B into the first and second output liquid
passages 3A and 3B. Such circulation of the braking liquid can
prevent an increase in the amount of depression of the brake pedal
P due to the absorption of the braking liquid into the first and
second reservoirs 8A and 8B. Moreover, the pulsation of the
pressure discharged from the first and second pumps 10A and 10B is
suppressed by the action of the first and second dampers 13A and
13B, and the operational feeling of the brake pedal P cannot be
degraded.
[0032] By operating the electric motor 11 in a state in which the
first and second suction valves 18A and 18B have been excited and
opened, and the first and second cut valves 17A and 17B have been
excited and closed during non-braking operation, the first and
second pumps 10A and 10B draw the braking liquid into themselves
from the master cylinder M and discharge the pressurized braking
liquid into the first and second liquid pressure passages 20A and
20B. By controlling the deexcitation and excitation of the
normally-opened type solenoid valves 6FL to 6RR and the
normally-closed type solenoid valves 9FL and 9RR in this state, the
turning motion control of the vehicle can be carried out.
[0033] More specifically, when the vehicle is in an over-steered
sate, the over-steered state can be overcome by operating the wheel
brakes for the turning outer wheels; and when the vehicle is in an
under-steered state, the under-steered state can be overcome by
operating the wheel brakes for the turning inner wheels.
[0034] Referring again to FIG. 1, the operation of the actuator 4
is controlled by a control unit U, to which the following detection
values are input: a detection value provided by a steering angle
sensor Sd as a target turning motion state determining means for
determining a target turning motion state for the vehicle based on
an amount of operation of a steering wheel H; a detection value
provided by a yaw rate sensor S as a turning motion state detecting
means for detecting an actual turning motion state of the vehicle;
and detection values provided by wheel speed sensors SFL, SFR, SRL
and SRR for detecting wheel speeds of the wheels WFL, WFR, WRL and
RR, respectively.
[0035] Referring to FIG. 3, an instrument panel 14a is provided
with a meter 15 for indicating the operated state of the actuator
4, a warning and the like, and a selector switch 16 as a switching
means for switching on and off of the turning motion control by the
driver's intention. The indication of the meter 15 is controlled by
the control unit U, and a switching signal provided by the selector
switch 16 is input to the control unit U.
[0036] Referring to FIG. 4, a section of the control unit U, which
is associated with the turning motion control, includes: an
actuator control means 21 for controlling the operation of the
actuator 4 to carry out the turning motion control of the vehicle;
and a wheel abnormal state detecting means 22 adapted to detect an
abnormal state of any of wheels and deliver the detection result to
the actuator control means 21.
[0037] The wheel abnormal state detecting means 22 is adapted to
detect the wheel abnormality by comparing the wheel speeds detected
by the wheel speed sensors SFL, SFR, SRL and SRR with one another.
The wheel abnormality is detected by a procedure shown in FIG.
5.
[0038] After learning of an initial valve at Step S1, it is
confirmed at Step S2 whether or not the learning of the initial
valve has been completed. After the completion of the learning of
the initial value, it is determined at Step S3 whether or not a
relation (1-VR)>a determination threshold value is established,
wherein an equation {(FL+RR)/(FR+RL)}=VR is established, when FL
and FR representing wheel speeds of the front left and front right
wheels, and RL and RR representing wheel speeds of the rear left
and rear right wheels. When (1-VR).ltoreq.the determination
threshold value is established, it is determined that the wheels
are not in an abnormal state, to proceed to Step S4 at which a
warning lamp is still turned off. On the other hand, when
(1-VR)>the determination threshold value is established, it is
determined that any of the wheels is in an abnormal state, to
proceed to Step S5 at which the warning lamp is turned on, and a
signal indicating that any of the wheels is in the abnormal state
is input to the actuator control means 21.
[0039] The abnormal state of the wheel means a state in which an
air pressure in the wheel has been decreased, or a tire has been
punctured, or a tire with a different diameter has been mounted on
the wheel by mistake. Thus, the wheel abnormal state detecting
means 22 also functions as an air-pressure decreased state
detecting means for detecting a decrease in air pressure of the
wheel.
[0040] The actuator control means 21 controls the actuator 4 so
that the steering angle of the steering wheel H detected by the
steering angle sensor Sd becomes a value in the target turning
motion state, and so that the actual turning motion state detected
by the yaw rate sensor Sc becomes close to the target turning
motion state. When the driver selects to operate the selector
switch 16 to stop the turning motion control, the control of the
actuator 4 by the actuator control means 21 for control of the
turning motion is stopped, unless the wheel abnormal state
detecting means 22 has detected the wheel abnormality.
[0041] Namely, in the actuator control means 21, the turning motion
control is carried out by a procedure shown in FIG. 6. At Step S11,
it is determined whether or not a flag F is at 1. The flag F is
based on a signal from the selector switch 16. When the driver
selects to stop the turning motion control, the flag F assumes
"1".
[0042] When it is confirmed at Step S11 that the flag F is "0", the
procedure is advanced to Step 13 at which vehicle stability assist
(VSA) is carried out. When it is confirmed at Step S11 that the
flag F is "1", the procedure is advanced to Step S13 at which it is
confirmed whether or not the wheel abnormal state detecting means
22 has detected a wheel abnormality. When the wheel abnormal state
detecting means 22 has not detected a wheel abnormality, the
procedure is advanced to Step S14 at which it is confirmed whether
or not an abnormality has been generated in the wheel abnormal
state detecting procedure and a warning has been issued. When it is
confirmed that the wheel abnormal state detecting procedure has
been normally performed, the procedure is advanced to Step S12.
[0043] When it is confirmed at Step S13 that the wheel abnormal
state detecting means 22 has detected a wheel abnormality, as well
as when it is confirmed at Step S14 that the wheel abnormal state
detecting means 22 has not detected a wheel abnormality but an
abnormality has been generated in the wheel abnormal state
detecting procedure and the warning has been issued, the procedure
is advanced to Step S15 at which the flag F is set at "0", to
advance to Step S12. In other words, when it is confirmed that the
wheel abnormal state detecting means 22 has detected the wheel
abnormality, as well as when it is confirmed that the wheel
abnormal state detecting means 22 has not detected any wheel
abnormality, but an abnormality has been found in the wheel
abnormal state detecting procedure and the warning has been
emitted, the flag F is forcibly set at "0", whereby the actuator
control means 21 controls the operation of the actuator 4 to
conduct the vehicle stability assist, irrespective of the switching
mode of the selector switch 16.
[0044] The operation of the present embodiment will be described
below. Values detected by the wheel speed sensors SFL, SFR, SRL and
SRR for detecting the wheel speeds of the wheels WFL, WFR, WRL and
WRR, respectively, are input to the wheel abnormal state detecting
means 22, which detects an abnormal state of any of the wheels
based on the comparison of the values detected by the wheel speed
sensors SFL, SFR, SRL and SRR with one another. When the wheel
abnormal state detecting means 22 has detected an abnormal state of
any of the wheels, the actuator control means 21 adapted to control
the turning motion of the vehicle by controlling the operation of
the actuator 4 controls the operation of the actuator 4,
irrespective of the switching mode of the selector switch 16
adapted to switch over a control-permitted state and a
control-stopped state of the actuator 4 upon operation by the
driver.
[0045] Therefore, even in a state in which the driver has operated
the selector switch 16 to stop the turning motion control by the
operation of the actuator 4, when the wheel abnormal state
detecting means 22 has detected an abnormal state of any wheel
based on comparison of the wheel speeds with one another, the
actuator control means 21 controls the actuator 4 so that the
actual turning motion state of the vehicle becomes close to the
target turning motion sate. Therefore, even if an abnormality of a
wheel has been generated in a state in which the turning motion
control by the operation of the actuator 4 has been stopped, the
stability of the vehicle can be ensured.
[0046] In the above-described embodiment, the abnormality of the
wheel is detected by the comparison of the wheel speeds of the
wheels WFL, WFR, WRL and WRR with one another, but sensors for
detecting air pressures may be mounted separately on the wheels
WFL, WFR, WRL and WRR so that decrease in the air pressures of the
wheels is detected by wireless signal transmission from the
sensors. When an air-pressure decreased state has been detected,
the control of the operation of the actuator 4 may be carried out,
irrespective of the switching mode of the selector switch 16. With
this arrangement, even in a state in which the driver has operated
the selector switch 16 to stop the turning motion control by the
operation of the actuator 4, the actuator control means 21 controls
the actuator 4 so that the actual turning motion state of the
vehicle becomes close to the target turning motion state, in
response to the air pressure decrease. Therefore, the stability of
the vehicle can be ensured.
[0047] Although the embodiment of the present invention has been
described in detail, it will be understood that the present
invention is not limited to the above-described embodiment, and
various modifications in design may be made without departing from
the subject matter of the invention defined in the claims.
* * * * *