Vehicular rear wheel steer angle control system
First Claim
1. A steering control system for a vehicle having at least one steerable front wheel and at least one steerable rear wheel, comprising:
- sensor means comprising means for sensing an actual front wheel steer angle of said vehicle,means for measuring a travel distance traveled by said vehicle,a controller for estimating a path traveled by a predetermined front point of a front portion of said vehicle during motion of said vehicle, from said actual front wheel steer angle sensed by said front wheel steer angle sensing means, and for determining a desired rear wheel steer angle required to cause a predetermined rear point of a rear portion of said vehicle, to follow said path of said front point, means for measuring a travel distance traveled by said vehicle, said controller comprising means for determining a value of a course angle of said front point indicative of a course of said front point from said actual front wheel steer angle each time said travel distance measured by said measuring means increases by a predetermined distance increment, means for storing a predetermined number of the course angle values which have been determined most recently by said course angle determining means, and means for determining said desired rear wheel steer angle from the oldest value of said predetermined number of said course angle values stored by said storing means,actuator means for steering said at least one rear wheel of said vehicle in accordance with said desired rear wheel steer angle.
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Accused Products
Abstract
A four wheel steer vehicle is equipped with a steering control system for controlling a rear wheel steer angle so that a rear end of the vehicle follows a path along which a front end moves. The control system includes a front wheel steer angle sensor, a controller for producing a control signal representing a desired rear wheel steer angle and an actuator for altering the rear wheel steer angle in response to the control signal produced by the controller. The controller estimates the path of the front end by calculating a value of a course angle of the front end from the front wheel steer angle each time the vehicle travels a predetermined short distance, and storing a predetermined number of the course angle values which are most recently determined. The controller determines the desired rear wheel steer angle so that the course angle of the rear end equals the oldest one of the stored course angle values of the front end.
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Citations
16 Claims
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1. A steering control system for a vehicle having at least one steerable front wheel and at least one steerable rear wheel, comprising:
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sensor means comprising means for sensing an actual front wheel steer angle of said vehicle, means for measuring a travel distance traveled by said vehicle, a controller for estimating a path traveled by a predetermined front point of a front portion of said vehicle during motion of said vehicle, from said actual front wheel steer angle sensed by said front wheel steer angle sensing means, and for determining a desired rear wheel steer angle required to cause a predetermined rear point of a rear portion of said vehicle, to follow said path of said front point, means for measuring a travel distance traveled by said vehicle, said controller comprising means for determining a value of a course angle of said front point indicative of a course of said front point from said actual front wheel steer angle each time said travel distance measured by said measuring means increases by a predetermined distance increment, means for storing a predetermined number of the course angle values which have been determined most recently by said course angle determining means, and means for determining said desired rear wheel steer angle from the oldest value of said predetermined number of said course angle values stored by said storing means, actuator means for steering said at least one rear wheel of said vehicle in accordance with said desired rear wheel steer angle. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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Specification