Rear wheel steering control for vehicle
First Claim
1. A vehicle comprising:
- a pair of front wheels and a pair of rear wheels,front wheel steering means for altering a front wheel steering angle, andrear wheel steering means including means for measuring distance travelled by the vehicle, means for sensing the front wheel steering angle, means for determining a target rear wheel steering angle equal to the product of the front wheel steering angle and a predetermined ratio, and means for controlling a rear wheel steering angle by steering the rear wheels so that the rear wheel steering angle is maintained equal to the target rear wheel steering angle when the distance measured by the distance measuring means is equal to or greater than a predetermined total distance, and so that the rear wheel sterring angle approaches the target rear wheel steering angle in accordance with distance travelled by the vehicle when the distance measured by the distance measuring means is smaller that the predetermined total distance.
1 Assignment
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Accused Products
Abstract
A rear wheel steering control system which determines a target rear wheel steering angle in accordance with a steering angle of front wheels of the vehicle and steers the rear wheels so that the rear wheel steering angle is maintained equal to the target rear wheel steering angle, and is arranged not to decrease the difference between the target angle and the actual rear wheel steering angle immediately to zero, but to decrease the difference gradually in accordance with a distance traveled by the vehicle, in order to prevent the rear wheels from being steered too much in a direction opposite to a steered direction of the front wheels especially when the vehicle speed is low, and thereby prevent the rear of the vehicle from bumping against an object lying alongside the vehicle.
22 Citations
13 Claims
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1. A vehicle comprising:
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a pair of front wheels and a pair of rear wheels, front wheel steering means for altering a front wheel steering angle, and rear wheel steering means including means for measuring distance travelled by the vehicle, means for sensing the front wheel steering angle, means for determining a target rear wheel steering angle equal to the product of the front wheel steering angle and a predetermined ratio, and means for controlling a rear wheel steering angle by steering the rear wheels so that the rear wheel steering angle is maintained equal to the target rear wheel steering angle when the distance measured by the distance measuring means is equal to or greater than a predetermined total distance, and so that the rear wheel sterring angle approaches the target rear wheel steering angle in accordance with distance travelled by the vehicle when the distance measured by the distance measuring means is smaller that the predetermined total distance. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A vehicle comprising:
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a pair of steerable front wheels and a pair of steerable rear wheels, front wheel steering means for altering the front wheel steering angle, and rear wheel steering means for determining a target rear wheel steering angle equal to the product of the front wheel steering angle and a predetermined ration, and steering the rear wheels so that any difference between a rear wheel steering angle and the target rear wheel steering angle is decreased gradually each time the vehicle travels a predetermined constant distance, means for determining the target rear wheel steering angle by multiplying the sensed front wheel steering angle with the predetermined ratio, and means for making the rear wheel steering angle equal to the sum of the currently sensed rear wheel steering angle and a correction quantity determined by multiplying a predetermined coefficient which is greater than zero and equal to or smaller than one with the difference obtained by subtracting the currently sensed rear wheel steering angle from the determined target rear wheel steering angle. - View Dependent Claims (9, 10, 11, 12)
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13. A method for steering rear wheels of a vehicle having steerable front wheels, comprising the steps of:
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measuring distance travelled by the vehicle, sensing the front wheel steering angle, determining a target rear wheel steering angle equal to the product of the front wheel steering angle and a predetermined ratio, and controlling a rear wheel steering angle by steering the rear wheels so that the rear wheel steering angle is maintained equal to the target rear wheel steering angle when the distance measured by the distance measuring means is equal to or greater than a predetermined total distance, and so that the rear wheel steering angle approaches the target rear wheel steering angle gradually in accordance with distance travelled by the vehicle when the distance measured by the distance measuring means is smaller than the predetermined total distance.
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Specification