Method for controlling a rear wheel steering device of a front and rear wheel steering vehicle
First Claim
1. A method for controlling a rear wheel steering device of a front and rear wheel steering vehicle, comprising the steps of:
- computing a target rear wheel steering angle according to an operating condition of a vehicle;
detecting an actual rear wheel steering angle;
detecting a load of a steering actuator of said rear wheel steering device;
defining a modified computed target rear wheel steering angle which is smaller than said computed target rear wheel steering angle when said load of the steering actuator is greater than a prescribed threshold value, and which is otherwise equal to said computed target rear wheel steering angle; and
actuating said steering actuator of the rear wheel steering device according to a deviation of said actual rear wheel steering angle from said modified computed target rear wheel steering angle.
1 Assignment
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Accused Products
Abstract
In a method for controlling a rear wheel steering device of a front and rear wheel steering vehicle, the target computed rear wheel steering angle is defined as a value smaller than the normal computed target rear wheel steering angle when the load of the steering actuator is greater than a prescribed threshold value, and which is otherwise equal to the normal computed target rear wheel steering angle, and the steering actuator is actuated according to a deviation of the actual rear wheel steering angle from the modified computed target rear wheel steering angle, typically with a duty ratio control. Thus, the rear wheel steering device can be operated in a satisfactory manner even when the output capacity of the actuator for the rear wheel steering device is limited, and the steering load is high. A high load condition typically occurs when the vehicle is stationary and when the steering wheel is turned sharply while the vehicle is traveling over a road surface having a high frictional coefficient.
15 Citations
5 Claims
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1. A method for controlling a rear wheel steering device of a front and rear wheel steering vehicle, comprising the steps of:
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computing a target rear wheel steering angle according to an operating condition of a vehicle; detecting an actual rear wheel steering angle; detecting a load of a steering actuator of said rear wheel steering device; defining a modified computed target rear wheel steering angle which is smaller than said computed target rear wheel steering angle when said load of the steering actuator is greater than a prescribed threshold value, and which is otherwise equal to said computed target rear wheel steering angle; and actuating said steering actuator of the rear wheel steering device according to a deviation of said actual rear wheel steering angle from said modified computed target rear wheel steering angle. - View Dependent Claims (2, 3, 4, 5)
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Specification