Research On Integrated H_∞/PID Control Of Vehicle Electrical Power Steering And Active Suspension System

In this paper, an integrated full model of EPS and ASS was built, considering the road inputs' influence to EPS and steering' to suspension, integrated control method for EPS and ASS based on H∞ optimal control strategy and PID theory has been studied given the complexity of the mutual disturbance between steering and suspension.Firstly, an integrated model for the vehicle with EPS instead of HPS (hydraulic power steering) when it steers was built based on steering model and the full vehicle dynamic model. Secondly, considering the stability of running, frequency-dependent weighting matrices to reduce the specific variables related to the vibration at specific bands of frequency were introduced and an optimal integrated controller for EPS and ASS was designed. Finally, in order to analyze the effects of the controller, controllers for EPS and the full vehicle dynamic system have been designed and applied, and the effects were compared using simulation tools. The results of the simulation show that, compared to the partly control system, the integrated control for EPS and ASS not only can save labor but also can effectively suppress the vibration of vehicle in the range of frequencies sensitive of human body, greatly improve the ride comfort and steering stability. Integrated control is realizable and effective. Hence, it provides some valuable theoretic reference for the research of vehicle active suspension control.New integrated controller for EPS and HASS (half active suspend system) was designed for test. Control circuit diagram and ECU (electrical control unit) were developed based MCS-51. After bench test, a road test was carried out in CH6353 with EPS and, the tests results demonstrate the effectiveness of proposed control methods for test.