Patent ID: 6148948
Filing Date: 2000-11-21
Classification: B62D

Abstract:
An electric power steering apparatus comprising:a steering torque sensor for detecting a steering torque of a steering system;a steering velocity sensor for detecting a steering velocity of said steering system;a steering torque differentiating section for producing a differential value of the steering torque;a motor control signal determining section including a target value setter which receives a signal value corresponding to the steering torque and which outputs a target value, said determining section for subtracting a value corresponding to the steering velocity from a value corresponding to the differential value of the steering torque to obtain a result of the subtraction and adding said target value to the result of the subtraction to thereby determine a motor control signal;an electric motor for providing an assist torque to said steering system;a motor drive section for driving said electric motor according to the motor control signal; andsaid steering torque differentiating section being arranged to output a differential value of a component of the steering torque which is free from a component near direct current and a high frequency component;wherein said steering torque differentiating section includes a band-pass filter that passes a component of the steering torque having a predetermined frequency band, and a differentiating circuit for achieving differentiating operation of said steering torque component passed through said band-pass filter, wherein said band-pass filter is a band-pass filter that passes a component of the torque signal having frequencies in the range of from 2 to 100 Hz.