Development of simplified steering simulator for design support of automotive electric power steering system

The estimation of steering characteristics such as steering feel by using only computer simulation technology is extremely difficult. To solve this problem, a steering simulator referred to as "Hard-in-the Loop" has been developed by researchers, in which the steering reaction force on the tie rod is produced by an AC servo motor and a ball screw, assuming mathematical models of the vehicle and tires are known. The purpose of this study is to develop a more simplified steering simulator, in which the electric motor in the EPS produces steering reaction torque and conventional assist torque. In this paper, emphasis is placed on the validity of this proposed means of generating steering reaction torque. The usefulness of this steering simulator was ascertained by comparing the test results of the simulator with the results obtained from computer simulation and actual vehicle testing.