Patent ID: 8560174
Filing Date: 2013-10-15
Classification: B62D

Abstract:
1. An electric power steering system, comprising: a steering force assisting device that supplies a steering system with assist force for assisting a steering operation; and a control unit that controls the steering force assisting device, wherein the control unit calculates a basic component of the assist force that is supplied to the steering system based on steering torque, and executes a compensation control for correcting the steering torque that is used for calculation of the basic component to increase the assist force that is supplied to the steering system when a steering state is a steering angle decreasing state or a steering angle maintained state, and wherein the control unit calculates a compensation component in accordance with the steering state by multiplying a basic compensation component, used to correct the steering torque to increase the assist force, by a transition coefficient that continuously changes in response to transition of the steering state indicated by a steering speed, executes a low-pass filter process on the compensation component and a low-pass filter process on the transition coefficient, and sets a first cutoff frequency of the low-pass filter process executed on the transition coefficient to a value lower than a second cutoff frequency of the low-pass filter process executed on the compensation component configured to suppress changes in the transition coefficient.