ELECTRIC POWER STEERING DEVICE

PROBLEM TO BE SOLVED: To provide an electric power steering device capable of gradually giving a limitation to the assist without making the steering feeling heavy and without suddenly giving uncomfortableness to a driver and without generating a dangerous condition due to the uncomfortableness of the driver. SOLUTION: This electric power steering device for controlling a motor for giving the steering assist force to a steering mechanism on the basis of a steering assist command value, which is computed by a computing means on the basis of the steering torque and a car speed and a motor current value, is provided with a function for continuing the assist by adding a limitation to the assist when a fine failure unnecessary to stop a system is generated. When a failure is generated, a character gain of the current control value corresponding to the steering torque is limited at 1/n and while a limitation target value is provided in the 1/n limitation characteristic. COPYRIGHT: (C)2003,JPO