ELECTRIC POWER STEERING SYSTEM
First Claim
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1. An electric power steering system comprising:
- a steering effort assist device that includes a motor as a drive source and applies an assist force to a steering system of a vehicle;
a torque sensor that generates a sensor signal according to a steering torque that acts on a steering shaft;
a control device that calculates an assist controlled variable that is a control component according to the assist force to be applied to the steering system, based on the steering torque obtained from the sensor signal, and controls the motor according to the assist controlled variable,wherein the control device makes the assist controlled variable zero when an absolute value of a steering speed is equal to or higher than a threshold set based on a possibility that an unintended steering behavior occurs.
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Abstract
When a steering speed reaches a steering speed determination threshold, a steering speed gain is set to “0”. As a result, a final basic assist controlled variable becomes “0”, and application of an assist force to a steering system is stopped. Therefore, repetition of so-called reverse assist that is a cause of occurrence of an unintended steering behavior, such as self-excited vibration, is stopped. Accordingly, the steering behavior is improved.
26 Citations
5 Claims
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1. An electric power steering system comprising:
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a steering effort assist device that includes a motor as a drive source and applies an assist force to a steering system of a vehicle; a torque sensor that generates a sensor signal according to a steering torque that acts on a steering shaft; a control device that calculates an assist controlled variable that is a control component according to the assist force to be applied to the steering system, based on the steering torque obtained from the sensor signal, and controls the motor according to the assist controlled variable, wherein the control device makes the assist controlled variable zero when an absolute value of a steering speed is equal to or higher than a threshold set based on a possibility that an unintended steering behavior occurs. - View Dependent Claims (2, 3, 4, 5)
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Specification