Search Results

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%.

A novel technology is proposed to predict vehicle rattle noise caused by shock absorbers. The shock absorber model is developed by analyzing the force of moving parts, hydronic characteristic of valves and physical characteristic of oil. The mount model is developed with the Maxwell method which combines series of spring and damping elements. The spring model is developed by curve interpolation of measured data, considering the hysteresis properties of the spring. The parameters of mass, wheelbase and tire etc. are measured and the vehicle body model is developed. The models of the shock absorber, mount, spring and vehicle body are combined together to develop the whole 4-wheel vehicle model to calculate the exciting forces of the shock absorbers. Furthermore, the transfer functions of sound pressure/force from the shock absorbers to the cabin are measured in real vehicle. The rattle noise is calculated using the exciting forces and the transfer functions.