Steering control system
First Claim
1. A steering control system for a motor vehicle, comprising:
- steering torque detecting means for detecting a steering input torque applied to an input end of a steering system;
steering angle detecting means for detecting a steering angle;
steering angular speed detecting means for detecting a change rate of the steering angle;
means for estimating a frictional coefficient of a road surface on which said vehicle is traveling;
maximum steering angle defining means for defining a maximum permissible steering angle according to a frictional coefficient estimated by said frictional coefficient estimating means; and
target torque computing means for determining a target output torque of a power actuator for said steering system according to outputs from said steering torque detecting means, said steering angle detecting means, said steering angular speed detecting means, and said maximum steering angle defining means.
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Accused Products
Abstract
In a steering control system for a motor vehicle, the magnitude of the steering assist torque is reduced from a normal value by a value depending on the ratio of the steering angle to a maximum permissible steering angle which is determined according to the frictional coefficient between the road surface and the road wheels so that excessive steering, which may otherwise occur on a slipper road surface, can be avoided. Additionally, the value by which the steering assist torque is reduced is increased with an increase in the steering speed so that a certain damping effect may be achieved in the system. This is particularly beneficial in preventing any ill effect which may arise when the steering wheel has a large mass of inertia, for instance by being equipped with an air bag system.
36 Citations
9 Claims
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1. A steering control system for a motor vehicle, comprising:
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steering torque detecting means for detecting a steering input torque applied to an input end of a steering system; steering angle detecting means for detecting a steering angle; steering angular speed detecting means for detecting a change rate of the steering angle; means for estimating a frictional coefficient of a road surface on which said vehicle is traveling; maximum steering angle defining means for defining a maximum permissible steering angle according to a frictional coefficient estimated by said frictional coefficient estimating means; and target torque computing means for determining a target output torque of a power actuator for said steering system according to outputs from said steering torque detecting means, said steering angle detecting means, said steering angular speed detecting means, and said maximum steering angle defining means. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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Specification