Modeling And Adaptive Control With Disturbance Attenuation For Automotive Active Suspension System

Nowadays, the vehicle not only improves our lives and enhances the efficients ofworking or producing, but also promotes the developments of economy and the wholecountry. With the advancements of science and technology, the requirements ofcomfortableness, reliability and maneuvering stability are increased. Therefore, theinvestigation and improvement of the vehicle system becomes more and more significant.It is known that the suspension system of vehicle is one of the most important componentsof which the performance designed is a key issue of modern vehicle.The kernel of active suspension system is the design of control strategy. In this thesis,the details about hydraulic active suspension system of the vehicles are studied. The actualmathematical model of the hydraulic active suspension system is established. According tothe special problem, the corresponding control method is proposed. By means of that, theperformance of active suspension system is improved and comfortableness of vehicles isenhanced. The main research findings are given:We established the model of hydraulic active suspension system of vehicles. After theresearch of the dynamic characteristics of vehicles in detail, on the basis of thenonlinearity of hydraulic servo system, we model the quarter part of active suspensionwith two degree of freedom and half-car model with four.Considering the parameter uncertainty in hydraulic servo system and the externaldisturbance, the control strategy of combing the adaptive backstepping and disturbanceattenuation is proposed and applied to the model of active suspension of quarter part ofvehicles. The theoretical research and simulation results both confirm the efficient ofcontroller.Taking into account of the problems of high cost of measurement or the system statesare not all measurable, a robust dynamic output feedback with disturbance attenuationcontroller is proposed and demonstrated by the half-car model . The theoretical researchand simulation results also confirm the efficient of controller. And the comparison with theconventional PID controller indicates the robustness in transient performance, the improvement in ride comfort as well as the enhancement in handling and stability ofvehicle.