Electric power steering apparatus

摘要

An electric power steering apparatus, which has an electric motor incorporated in a steering system to provide steering power assist directly to the steering system to thereby reduce manual steering effort required by the driver, includes a steering torque differentiating section arranged to output a differential value of a component of the steering torque which is free from a near-dc component and a high frequency component, a motor control signal determining section for subtracting a value corresponding to the steering velocity from a value corresponding the steering torque and adding the value corresponding to the steering torque to a value corresponding to the differential value to thereby determine a motor control signal, and a motor drive section for driving the electric motor on the basis of the motor control signal. With this arrangement, the electric power steering apparatus can improve the response characteristics of the steering power assist system while preventing undue increase in the gain of the control system at low frequencies in the range of 2 to 4 Hz, for example.