Vehicle steering system determines the direction of vehicle and delivering the road condition. A manual steering system consists of mechanical connections between the steering wheel and tires. Recent power steering system adds a actuator to help driver to steer easily at low speed. But, injury due to the steering shaft at front collision occurs by mechanical structure and decrease of engine power due to power steering pump. To solve these problems, electronic power steering system which connects the steering wheel and tires with electronic connection is proposed. The electronic power steering system has advantages, decrease of engine load and increase of driver safety because of electronic connection. And, the ratio between driver‘s steering torque and steering torque of tires can be controlled freely, the torque which is delivered from road to the driver through tires and steering wheel can be controlled more easily than the mechanical power steering system. In this paper, the ratio of delivering steering torque and the magnitude of force to be delivered from road to driver has been controlled using fuzzy controller, and it's effectiveness has been shown through simulation results.
