Research On Vehicle Electro-Hydraulic Active Suspension Based On Model Predictive Control

With the development of economy, improvement of people’s living standard and rapid growth of the automobile possession. People have proposed higher and higher demands, for the vehicle ride comfort and handle stability. Suspension system is an important part of the vehicle, and it plays a key role on the vehicle performance. With the characteristics of fast response and excellent control performance, active suspension has become the research hotspot in the field of suspension.This paper chose electro-hydraulic active suspension system as the research object to analyze the whole control system. Firstly, the mathematical model of random road,1/4vehicle suspension system and electro-hydraulic servo system were built. According to these mathematical models, the state space equation of the suspension system and hydraulic servo system integration model is established and the transfer function of servo valve and amplifier were solved.A model predictive controller was designed by using nonlinear model predictive control theory for the electro-hydraulic active suspension system integration model. The control system mainly includes prediction model, rolling optimization, online correction, reference trajectory and the controlled object. The rolling optimization idea of predictive control theory is online repeatedly optimization based on actual output feedback information, it can considers the effect of indefinite factors in real time way and correct the error promptly. The simulation model of predictive controller and the whole system were built using the software of Matlab/Simulink. The simulation results showed that the electro-hydraulic active suspension system with a model predictive controller can effectively reduce the vibrations caused by road excitation and improve the ride comfort apparently.The mathematical model of the integrated control system about active suspension system and electric power steering system is established. With the steering wheel’s step input, the model predictive integrated control system is constructed and simulated. The simulation results show that the integrated control system, compared with the passive control system, optimizes the whole dynamics performance in its running condition and improve the ride comfort, handling stability, running smoothness and safety.