Research and Optimizations of CV-EPS Stability for Heavy Commercial Vehicle

In response to the problems of heavy commercial vehicles such as high steering axle load, high steering resistance, and high energy consumption, steering products pure electrification is an inevitable trend in technological development after the appearance of Electric Hydraulic Powered Steering (Further Called EHPS). This article introduces the structure and the compositions of the Commercial Vehicle Electrical Power Steering (Further Called CV-EPS) system briefly, simplifies and analyses the force on each component of the system, and elaborates on the mathematical models of each structure in detail. Based on the vehicle resistance model and the assist force characteristic curve, the transfer functions of the entire CV-EPS system are obtained. In the torque control section, an electric current loop PID controller is designed, and the PID parameters are effectively tuned based on the transfer functions. Regarding to the general problem of phase delay, a phase lead sector was designed for compensation. Finally, to analyse the stability of the system, a comprehensive simulation model of CV-EPS was built in the Simulink environment. The simulation results indicate that the CV-EPS system of heavy commercial vehicles has ideal dynamic performance and stability, and this method has great reference value and practical significance for improving the steering performance of the entire vehicle and optimizing the driver's steering feeling.