JPS649063A - Electrical power steering device - Google Patents

Abstract

PURPOSE:To prevent the manipulation of a steering wheel from becoming heavy even during abrupt steering operation, by providing such an arrangement that an output current fed to a torque motor is compensated when an abrupt steering operation is performed so as to maintain the rate of assist torque to steering wheel torque at a predetermined value. CONSTITUTION:A first torque sensor 11 detects a steering wheel torque inputted to a steering wheel shaft 16 while a second torque sensor 23 detects an assist torque give by a torque motor 20. An electric control device 80 compares both torques with each other end controls output current applied to the torque motor 20 so that the assist torque a ways has a predetermined rate with respect to the steering wheel torque. When an abrupt steering operation is performed, the above-mentioned output current is compensated to a value which is different from that in the case of moderate steering operation so that a resisting torque due to the rotational inertia of the torque motor 20 is canceled out, thereby it is possible to maintain the rate of the assist torque to the steering wheel torque at a predetermined value.