Control system for a front and rear wheel steering vehicle
First Claim
1. A control system for a front and rear wheel steering vehicle having front wheels which are steered by turning of a steering wheel, and rear wheels which are automatically steered by a powered actuator according to an operating condition of said vehicle, comprising:
- standard yaw rate determining means for determining a standard yaw rate according to a steering angle of said steering wheel;
actual yaw rate detecting means for detecting an actual yaw rate acting upon said vehicle;
computing means for computing a deviation between said standard yaw rate and said actual yaw rate;
feedback control means for controlling a steering angle of said rear wheels according to said deviation computed by said computing means; and
feed forward control means for controlling, in cooperation with said feedback control means, said steering angle of said rear wheels according to said steering angle of said steering wheel.
1 Assignment
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Accused Products
Abstract
A steering angle of rear wheels are steered according to a deviation between an ideal yaw rate response and an actual yaw rate response to the given steering wheel input. By combining feedback control and feed forward control, immunity from external disturbances and lateral stability can be both ensured each at a high level over the entire range of vehicle speed. By appropriately selecting the transfer function of the control system, it is possible to achieve desired responsiveness and stability. Furthermore, the vehicle response in the range where the cornering force of tires tends to saturate can be improved, and it is therefore possible to neutralize the steering property over the entire vehicle speed range.
36 Citations
10 Claims
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1. A control system for a front and rear wheel steering vehicle having front wheels which are steered by turning of a steering wheel, and rear wheels which are automatically steered by a powered actuator according to an operating condition of said vehicle, comprising:
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standard yaw rate determining means for determining a standard yaw rate according to a steering angle of said steering wheel; actual yaw rate detecting means for detecting an actual yaw rate acting upon said vehicle; computing means for computing a deviation between said standard yaw rate and said actual yaw rate; feedback control means for controlling a steering angle of said rear wheels according to said deviation computed by said computing means; and feed forward control means for controlling, in cooperation with said feedback control means, said steering angle of said rear wheels according to said steering angle of said steering wheel. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A control system for a front and rear wheel steering vehicle having front wheels which are steered by turning of a steering wheel, and rear wheels which are automatically steered by a powered actuator according to an operating condition of said vehicle, comprising:
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standard yaw rate determining means for determining a standard yaw rate according to a steering angle of said steering wheel; actual yaw rate detecting means for detecting an actual yaw rate acting upon said vehicle; computing means for computing a deviation between said standard yaw rate and said actual yaw rate; feedback control means for controlling a steering angle of said rear wheels according to said deviation computed by said computing means; and means for reducing the gain of said standard yaw rate determining means when a lateral acceleration is greater than a predetermined level.
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Specification