Design Method of Electric Power Steering Control based on Vehicle Motion Characteristics

In this paper, we propose a new Electric Power Steering (EPS) control and its design method. This control enables to transmit a vehicle motion information to a driver through a steering wheel. First, kinetic equations including characteristics of both EPS system and vehicle lateral motion are shown. Control-design policies are then derived from the frequency responses and the step responses of the vehicle equipped with EPS. In particular we regard the vehicle motion which is caused by a disorder of a lateral force balance between front and rear wheels as an important information that should be transmitted to a driver. A generalized plant is designed based on those equations and policies, and H-infinity controller is calculated from it. Finally, its effectivenesses are shown by vehicle experimental results.