A Coupled System Simulator for Electric Power Steering System

Electric power steering system has been widely used in passenger cars to replace hydraulic power steering system. In this paper, a coupled system simulator for dual-pinion electric power steering system is developed and its dynamics is verified using experimental data. The mechanical subsystem model is developed using mass, spring-damper and experimental data with hysteresis characteristic. For the control subsystem, the controller model is developed by transplanting control program from the controller in real vehicle to the simulator. For the electric subsystem, the motor model is developed using the map of current to torque which is created by magnetic field analysis in advance. The three subsystems are combined to form the complete system simulator and numerical simulation is performed. The simulation results are compared to the experimental data and the error is less than 10%. The coupled EPS system simulator produces accurate predictions of system dynamics and can support engineers in the analysis and design of real system effectively.