ELECTRIC POWER STEERING DEVICE FOR VEHICLE

摘要

PROBLEM TO BE SOLVED: To easily adjust the characteristic of change in assist force for steering torque in an electric power steering device assisting the operation of a steering wheel. SOLUTION: An electric motor 14 assists the turning movement of a steering wheel 11 by its rotation. A CPU 41 determines an assist current value which corresponds to he steering torque and the car speed respectively detected by a steering torque sensor 21 and a speed sensor 22 by referring to an assist map prepared in a memory unit 42. The assist current value to which an offset value is added, is multiplied by the gain factor to calculate a command current value, and to control the rotation of the electric motor 14 in response to the command current value. The offset value and the gain factor are chosen out of plural candidate values previously stored in the memory unit 42 by operating a changeover switch 24.