Abstract: An electrically operated power steering device connected to a steering system of a motor vehicle to provide supplementary steering power by means of an electric motor. A motor control unit for the electrically operated power steering device controls the rotational direction and output torque of the electric motor by the sum of an assistance signal based on the signal from a torsional torque sensor and a velocity sensor in the steering system, a restoration signal based on the output signal from a steering angle sensor, and an auxiliary assistance signal based on the output signal from the torsional torque sensor in the steering system as a command signal.

Abstract: A system having a motor operatively connected to a steering system for reducing the steering effort is provided with a torsion torque sensor for detecting torsion torque in the steering system during a steering operation, and a steering angle sensor provided for detecting steering angle. In response to the output signal of the torsion torque sensor, an assist signal is produced, and in response to the output of the steering angle sensor, a return signal is produced and a reducing signal dependent on the speed of steering of a steering wheel is produced. The reducing signal is added to the assist signal thereby reducing the assist signal, so that the output torque of the motor is decreased. When the steering wheel is stopped in a steered position the output torque of the motor is produced in the return direction of the steering wheel.