Rear wheel steering control system for vehicle
First Claim
1. A steering control system for a vehicle, comprising;
- a rear steering actuator for varying an actual rear wheel steer angle of said vehicle in accordance with a control signal representing a desired rear wheel steer angle,sensor means for sensing a steering angle of said vehicle,controller means for determining a first product by multiplying a time rate of change of said steering angle by a derivative coefficient, and producing said control signal in accordance with said first product, said controller means increasing said derivative coefficient with increase in a variable which is one of said steering angle and a lateral acceleration of said vehicle when said variable is greater than a predetermined threshold value.
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Accused Products
Abstract
A vehicle control system has a controller comprising a first section for producing a control signal to control the rear wheel steer angle so that the rear wheel steer angle remains equal to a linear combination of a proportional term obtained by multiplying the front wheel steer angle by a proportional coefficient, and a negative derivative term obtained by multiplying the time rate of change of the front wheel steer angle by a derivative coefficient, and a second section which increases the rear wheel steering amount in the direction opposite to the front wheel steering direction by increasing the absolute value of the derivative coefficient with increase in the lateral acceleration of the vehicle or the front wheel steer angle, in order to improve the yawing characteristic of the vehicle in the high lateral acceleration range.
20 Citations
13 Claims
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1. A steering control system for a vehicle, comprising;
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a rear steering actuator for varying an actual rear wheel steer angle of said vehicle in accordance with a control signal representing a desired rear wheel steer angle, sensor means for sensing a steering angle of said vehicle, controller means for determining a first product by multiplying a time rate of change of said steering angle by a derivative coefficient, and producing said control signal in accordance with said first product, said controller means increasing said derivative coefficient with increase in a variable which is one of said steering angle and a lateral acceleration of said vehicle when said variable is greater than a predetermined threshold value. - View Dependent Claims (8, 9, 10, 11)
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2. A steering control system for a vehicle, comprising;
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a rear steering actuator for varying an actual rear wheel steer angle of said vehicle in accordance with a control signal representing a desired rear wheel steer angle, sensor means for sensing a steering angle of said vehicle, controller means connected with said sensor means, said controller means comprising preparing means for generating a first input signal proportional to said steering angle, and a second input signal representing a lateral acceleration of said vehicle, and control signal generating means for generating said control signal in accordance with said first and second input signals so that said desired rear wheel steer angle represented by said control signal is proportional to a difference resulting from subtraction of a first product obtained by multiplying a time rate of change of said first input signal by a derivative coefficient, from a second product obtained by multiplying said first input signal by a proportional coefficient, said generating means comprising derivative coefficient determining means for increasing said derivative coefficient in accordance with said second input signal when said second input signal is higher than a predetermined threshold value. - View Dependent Claims (3, 4, 5, 6, 7, 12, 13)
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Specification