Patent ID: 6448728
Filing Date: 2002-09-10
Classification: B62D

Abstract:
An electric power steering apparatus comprising:an electric motor which applies an assist steering torque to the steering system of a vehicle; a steering torque sensor which detects the manual steering torque of said steering system; a vehicle speed sensor which detects the vehicle speed of said vehicle; a revolution number sensor for said electric motor which detects the revolution number of said electric motor; a controller which generates a control signal for controlling said electric motor; and a driver which generates a driving signal for driving said electric motor based on said control signal, said controller including: a reference torque signal setting unit which generates a reference torque signal which becomes high when the detected signal becomes high based on at least the signal detected from said steering torque sensor; a correction torque signal setting unit which generates a correction torque signal, which becomes high when the detected signal becomes high based on at least the signals detected from said revolution number sensor for the electric motor and from the vehicle speed sensor; and a target torque signal calculator which subtracts said correction torque signal from said reference torque signal to output a target torque signal to said electric motor; said controller also making said correction torque signal high when failure of the vehicle speed sensor is detected.