EP0150856A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Auxiliary steering system for wheeled vehicle
Assignee: Nissan Motor Co Ltd
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Filing: 1985-01-31
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Granted: —
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Expires: 2005-01-31
Abstract
Abstract @ In addition to a conventional steering system for steering a vehicle through the front wheels (2) in accordance with an angular displacement of the steering wheel, the vehicle is equipped with a negative feedback steering control system (7) which steers the vehicle through the front or rear wheels in accordance with an instantaneous yaw rate of the vehicle. The feedback system has a vehicle behavior sensor (3') for sensing the yaw rate, and a control circuit (9) which determines an actual quantity which is equal to the yaw rate or a linear combination of the yaw rate and the time derivative of the yaw rate and a reference quantity which is a function of the angular displacement and the vehicle speed, so designed as to be approximately equal to the yaw rate if there is no disturbance. The control circuit produces a feedback signal proportional to a difference between the actual quantity multiplied by a first coefficient and the reference quantity multiplied by a second coefficient. In response to the feedback signal, an actuator (6) corrects the direction of the front or rear wheels in such a direction as to reduce the yaw rate. A lateral acceleration of the vehicle may be used in place of the yaw rate.
Inventors
- 👤 Yasuji Shibahata
- 👤 Yukio Fukunaga
- 👤 Yasumasa Tsubota
- 👤 Takaaki Uno
- 👤 Yuji Okuyama
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-23 21:00
CPC Classifications
G; G05; G05D; G05D1/00; G05D1/08; G05D1/0891; B; B62; B62D; B62D7/00; B62D7/06; B62D7/14; B62D7/15; B62D7/159
Claims Analysis
Total Claims: 34
Claim 1
Independent Claim
171 words
A vehicle comprising: road wheels (2,27), a steering wheel (18), a steering mechanism (14,15,19,20,21,22) for steering the vehicle by altering the direction of at least one of the road wheels in accordance with an angular displacement of the steering wheel, a steering angle sensor for sensing the angular displacement of the steering wheel, vehicle behavior sensing means (3',3") for sensing at least one variable, which is indicative of an actual turning behavior of the vehicle, negative feedback means (9) connected with the steering angle sensor and the vehicle behavior sensing means for producing a negative feedback signal in accordance with a difference between an actual quantity determined in accordance with the variable sensed by the vehicle behavior sensing means and a reference quantity determined in accordance with the angular displacement sensed by the steering angle sensor, and actuating means (6) for steering the vehicle by altering the direction of at least one of the road wheels in accordance with the negative feedback signal in such direction as to reduce the variable.
Claim 2
Dependent Claim
171 words
A vehicle comprising: road wheels (2,27), a steering wheel (18), a steering mechanism (14,15,19,20,21,22) for steering the vehicle by altering the direction of at least one of the road wheels in accordance with an angular displacement of the steering wheel, a steering angle sensor for sensing the angular displacement of the steering wheel, vehicle behavior sensing means (3',3") for sensing at least one variable, which is indicative of an actual turning behavior of the vehicle, negative feedback means (9) connected with the steering angle sensor and the vehicle behavior sensing means for producing a negative feedback signal in accordance with a difference between an actual quantity determined in accordance with the variable sensed by the vehicle behavior sensing means and a reference quantity determined in accordance with the angular displacement sensed by the steering angle sensor, and actuating means (6) for steering the vehicle by altering the direction of at least one of the road wheels in accordance with the negative feedback signal in such direction as to reduce the variable.
Claim 3
Dependent Claim
29 words
A vehicle according to Claim 1, wherein the variable to be sensed by the vehicle behavior sensing means is a yaw rate or, a lateral acceleration of the vehicle.
Claim 4
Dependent Claim
51 words
A vehicle according to Claim 2, further comprising a vehicle speed sensor (12) for sensing the speed of the vehicle, and wherein the feedback means determines the reference quantity in accordance with the angular displacement sensed by the steering angle sensor and the vehicle speed sensed by the vehicle speed sensor.
Claim 5
Dependent Claim
56 words
A vehicle according to Claim 3, wherein the reference quantity is a function of the angular displacement of the steering wheel and the vehicle speed, and approximately equal to the variable determined by the angular displacement of the steering wheel and the vehicle speed in a predetermined steady state of a turning movement of the vehicle.
Claim 6
Dependent Claim
37 words
A vehicle according to Claim 4, wherein the value of the feedback signal is directly proportional to a difference between the actual quantity multiplied by a first coefficient and the reference quantity multiplied by a second coefficient.
Claim 7
Dependent Claim
75 words
A vehicle according to Claim 5, wherein the vehicle behavior sensing means senses the yaw rate of the vehicle, the variable being the yaw rate of the vehicle, the reference quantity being approximately equal to wherein N is a steering gear ratio of the vehicle, ℓw is a wheel base of the vehicle, K is a predetermined stability factor, V is the vehicle speed, and 6 is the angular displacement . of the steering wheel.
Claim 8
Dependent Claim
26 words
A vehicle according to Claim 6, wherein the actual quantity is equal to the yaw rate of the vehicle sensed by the vehicle behavior sensing means.
Claim 9
Dependent Claim
28 words
A vehicle according to Claim 6, wherein the actual quantity is equal to a linear combination of the yaw rate and the time rate-of-change of the yaw rate.
Claim 10
Dependent Claim
45 words
A vehicle according to Claim 8, wherein the vehicle behavior sensing means comprises a yaw rate sensor (3') for sensing the yaw rate of the vehicle, and a differentiator (61) for finding the time rate-of-change of the yaw rate sensed by the yaw rate sensor.
Claim 11
Dependent Claim
170 words
A vehicle according to Claim 8, wherein the vehicle behavior sensing means comprises a front lateral G sensor (52) mounted on a front portion of the vehicle for sensing a lateral acceleration of the front portion, a rear lateral G sensor (53) mounted on a rear portion of the vehicle for sensing a lateral acceleration of the rear portion, a differential amplifier (54) for producing an output which is equal to (G 1 -G 2 )/ℓ where G 1 is the lateral acceleration sensed by the front lateral G sensor, G 2 is the lateral acceleration sensed by the rear lateral G sensor and & is a distance between the front and rear lateral G sensors, and an integrator (63) for finding the time integral of the output of the differentia amplifier, and wherein the feedback means regards the time integral of the output of the differential amplifier as the yaw rate of the vehicle, and the output of the differential amplifier as the time rate-of-change of the yaw rate.
Claim 12
Dependent Claim
39 words
A vehicle according to Claim 6, wherein the actual quantity is equal to a linear combination of the yaw rate of the vehicle, and the time rate-of-change of the lateral acceleration of the center of gravity of the vehicle.
Claim 13
Dependent Claim
82 words
A vehicle according to Claim 5, wherein the vehicle behavior sensing means senses a lateral acceleration of the center of gravity of the vehicle, the variable being the lateral acceleration of the center of gravity of the vehicle, the reference quantity being approximately equal to where N is a steering gear ratio, 1 w is a wheel base of the vehicle, K is a predetermined stability factor, V is the vehicle speed, and 0 is the angular displacement of the steering wheel.
Claim 14
Dependent Claim
23 words
A vehicle according to Claim 12, wherein the actual quantity is equal to the lateral acceleration sensed by the vehicle behavior sensing means.
Claim 15
Dependent Claim
35 words
A vehicle according to Claim 12, wherein the actual quantity is equal to a linear combination of the lateral acceleration sensed by the vehicle behavior sensing means, and the time rate-of-change of the lateral acceleration.
Claim 16
Dependent Claim
50 words
A vehicle according to Claim 14, wherein the vehicle behavior sensing means comprises a center lateral G sensor mounted on the vehicle for sensing the lateral acceleration of the center of gravity of the vehicle, and a differentiator for differentiating the lateral acceleration sensed by the center lateral G sensor.
Claim 17
Dependent Claim
31 words
A vehicle according to Claim 12, wherein the actual quantity is equal to a linear combination of the lateral acceleration and the time rate-of-change of the yaw rate of the vehicle.
Claim 18
Dependent Claim
68 words
A vehicle according to Claim 16, wherein the vehicle behavior sensing means comprises a center lateral G sensor (3") mounted on the vehicle for sensing the lateral acceleration of the center of gravity of the vehicle, a yaw rate sensor (3') mounted on the vehicle for sensing the yaw rate of the vehicle, and a differentiator (61) for differentiating the yaw rate sensed by the yaw rate sensor.
Claim 19
Dependent Claim
87 words
A vehicle according to Claim 16, wherein the vehicle behavior sensing means comprises a front G sensor (52) mounted on a front portion of the vehicle for sensing a lateral acceleration of the front portion of the vehicle, and the feedback means receives the output of the front lateral G sensor and regards the output of the front G sensor as the linear combination of the lateral acceleration of the center of gravity of the vehicle and the time rate-of-change of the yaw rate of the vehicle.
Claim 20
Dependent Claim
22 words
A vehicle according to Claim 5, wherein the first coefficient is equal to one, and the second coefficient is equal to 0.7.
Claim 21
Dependent Claim
34 words
A vehicle according to Claim 5, wherein the feedback means comprises a feedback coefficient adjusting means (60) for varying a coefficient difference that remains after the second coefficient is subtracted from the first coefficient.
Claim 22
Dependent Claim
21 words
A vehicle according to Claim 20, wherein the feedback coefficient adjusting means increases the coefficient difference as the vehicle speed increases.
Claim 23
Dependent Claim
26 words
A vehicle according to Claim 20, wherein the feedback coefficient adjusting means increases the coefficient difference when a side wind becomes stronger than a predetermined level.
Claim 24
Dependent Claim
21 words
A vehicle according to Claim 20, wherein the feedback coefficient adjusting means increases the coefficient difference when the weather becomes rainy.
Claim 25
Dependent Claim
32 words
A vehicle according to Claim 20, wherein the feedback coefficient adjusting means increases the coefficient difference as a road condition under the vehicle becomes worse for the directional control of the vehicle.
Claim 26
Dependent Claim
25 words
A vehicle according to Claim 20, wherein the feedback coefficient adjusting means increases the coefficient difference as the acceleration or deceleration of the vehicle increases.
Claim 27
Dependent Claim
21 words
A vehicle according to Claim 20, wherein the feedback coefficient adjusting means increases the coefficient difference as the vehicle weight increases.
Claim 28
Dependent Claim
24 words
A vehicle according to Claim 20, wherein the feedback coefficient adjusting means increase the coefficient difference as the weight on the rear wheels increases.
Claim 29
Dependent Claim
22 words
A vehicle according to Claim 20, wherein the feedback coefficient adjusting means varies the coefficient difference in accordance with a manual operation.
Claim 30
Dependent Claim
93 words
A vehicle according to Claim 5, wherein the road wheels comprises a pair of steerable front wheels (2) and a pair of rear wheels (27), and the steering mechanism (14,15,19,20,21,22) is connected between the steering wheel and the front wheels for controlling the direction of the front wheels in accordance with the angular displacement of the steering wheel, and wherein the actuating means (6) is connected with the steering mechanism so that the actuating means can correct the direction of the front wheels in accordance with the feedback signal through the steering mechanism.
Claim 31
Dependent Claim
106 words
A vehicle according to Claim 29, wherein the steering mechanism comprises a steering gear assembly which comprises a pinion (21) rotated by the steering wheel, a rack (20) which engaged with the pinion and is capable of steering the front wheels, and a gear housing (22) enclosing the rack and pinion, the gear housing being supported on a body of the vehicle through rubber bushes (23) so that the gear housing is movable longitudinally, and wherein the actuating means comprises a front hydraulic actuator comprising a cylinder fixed to the vehicle body and a piston connected with the gear housing for moving the gear housing longitudinally.
Claim 32
Dependent Claim
71 words
A vehicle according to Claim 29, wherein the actuating means comprises a front hydraulic actuator, and the steering mechanism comprises a recirculating ball type steering gear having a pitman arm (19a), right and left steering linkages (13,14) for supporting the right and left front wheels, and a tie rod (15) connecting the right and left steering linkages, the tie rod being connected with the pitman arm through the front hydraulic actuator.
Claim 33
Dependent Claim
84 words
A vehicle according to Claim 5, wherein the road wheels comprises a pair of steerable front wheels (2) and a pair of rear wheels (27), and the steering mechanism (14,22) is connected between the steering wheel and the front wheels for controlling the direction of the front wheels in accordance with the angular displacement of the steering wheel, and wherein the actuating means (6) is connected with the rear wheels for altering the direction of the rear wheels in accordance with the feedback signal.
Claim 34
Dependent Claim
228 words
A vehicle according to Claim 32, wherein the actuating means comprises a right pair of first and second lateral rods (40,41) extending along a lateral line of the vehicle and connecting the right rear wheel to the vehicle body, and a left pair of first and second lateral rods (40,41) extending along the lateral line of the vehicle and connecting the left rear wheel to the vehicle body, the first lateral rod of each pair being divided into an inner rod portion and an outer rod portion, the rear actuating means further comprising a right rear hydraulic actuator disposed between the inner and outer rod portions (40a,40b) of the first lateral rod of the right pair so that the length of the first lateral rod is variable, and a left rear hydraulic actuator disposed between the inner and outer rod portions of the first lateral rod of the left pair so that the length of the first lateral rod is variable, each of the rear actuators comprises a cylinder fixed to the inner rod portion (40b), a piston (6a) separating two working fluid chambers, and a piston rod (6b) which is fixed with the piston and the outer rod portion, and formed with an outerward flange interposed between two rubber bushes (45,46) so that the flange deflects one of the rubber bushes when the piston rod moves axially.
References Cited (Backward Citations)
No citation records indexed.
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