Electric motor assisted power steering device.

摘要

An electric motor assisted power steering device for an automobile is disclosed which comprises a duplicate torque direction determination system. The power steering device comprises, in addition to a microcomputer (3) for determining the amount and direction of the auxiliary torque which is to be provided by the electric motor, an analog direction determined circuit (17) for determining the direction of the auxiliary torque. The microcomputer (3) determines, on the basis of the output of the torque sensor, the direction of the auxiliary torque and outputs a corresponding right or left direction signal. A first AND gate (20A) performs an AND operation on the two right direction signals outputted from the microcomputer and the analog circuit; a second AND gate (20B) performs an AND operation on the two left direction signals. The motor driver circuit (10) controls the direction of the current supplied to the electric motor (14) in accordance with the output of the first and the second AND gate.