Patent ID: 6246197
Filing Date: 2001-06-12
Classification: B62D

Abstract:
An electric power steering controller comprising:a motor for generating a torque for assisting a driver's steering torque;a steering unit for transmitting the steering torque from a steering wheel to wheels in an automobile;voltage detection means calculating or receiving one or both of a motor drive voltage instruction value and an inter-terminal voltage measurement value for detecting a voltage applied to the motor;current detection means for detecting a current running through a coil of the motor;rotation speed estimation means for estimating a rotation speed of the motor based on said voltage detected by the voltage detection means and said current detected by the current detection means; anda control unit for calculating a target current for driving the motor based on at least said rotation speed estimated by the rotation speed estimation means,wherein the voltage detection means determines a correction voltage, based on a detection current value detected by the current detection means or said target current and outputs an application voltage estimation value, where said application voltage estimation value is obtained by subtracting said correction voltage from one or a combination of said motor drive voltage instruction value and said inter-terminal voltage measurement value of the motor, andwherein the rotation speed estimation means estimates the rotation speed of the motor based on the application voltage estimation value from the voltage detection means and the detection current value from the current detection means.