Research On Control Strategy Of Project Vehicles Full Hydraulic Active Suspension System

The subject is the project that "State211 Project" electro-hydraulic-proportional experimental vehicles. Research 6x6 project vehicles on hydraulic active suspension system and Optimal control, and solve the stable and comfortable issues in high-speed vehicles mainly.As the requirements on the working quality of project vehicles that work in occasions frequently that the pavement changes acutely, especially the project vehicles and mine-vehicles, the pavement conditions and load conditions even worse, so the vehicles wiil be impacted inevitably from the vertical direction of road when it running and produce the upper and lower vibration. Because the project vehicles have different Load when it runs, and the level of load distribution in vehicles are not the same, so make the vehicles height and levelChange and many performance of vehicles and life to be impacted ( such as comfort of running and operations stability, comfort of crew.etc).But active suspension can changes suspension parameters to achieve optimal performance adaptively, according to force and State of vehicles. Therefore, the project vehicles can use active suspension to reduce the impact of vibration for better so that they could very well increase the performance on the passing, safety and comfort requirements of project vehicles.The project intention is to study the full hydraulic active suspension control method. Applying the optimal control theory, according to the system state variables, receive a minimum of optimal suspension system integrated control target through evaluating Indicators. The purpose of this study is the active suspension system control strategy research about a hydraulic project vehicles, so this paper selects single-wheel and two-freedom vehicles model.After had a in-depth analysis about hydraulic active suspension system, we advance the optimal control project and provethe feasibility of control and superiority through computer simulation and analysis of the resultsThis text is divided into six chapters altogether.Chapter1: described the development of the situation at native and abroad of project vehicles suspension and the development of hydraulic suspension firstly, and gave a briefing on the classification and role of suspension and the popular control method, meanwhile expounded the purpose and content on the topic.Chapter2: introduced the configuration and principle of the 6x6 hydraulic active suspension system, as accumulator in the hydraulic system is very important, therefore, analysised the accumulator of static and dynamic characteristics of a more detailed and established the model about electro-hydraulic proportional valve-controlled suspension hydraulic cylinder.Chapter3: introduced performance indicators of the suspension system and the selection of suspension model firstly, and then established a road input model and the active suspension dynamics equation about the single-wheel. The paper used a filter white noise as the road input model, the white noise can be generated directly by calling MATLAB function WGN (M, N, P). Finally, according cylinder valve control theory, established hydraulic model about the active suspension system, calculated the relationship between the piston rod and valve-core displacement.Chapter4: introduced the linear quadratic Gauss LQG optimal control and Fully state information optimal control theory, and analysised the controllability and observability of the system, given the determination method. Set up a LQG Controller by using suspension displacement and Tire suspension and Body acceleration as performance indicators. According to the extreme principle, get the optimal controlling power. Active Suspension optimal controller design can be completed by function [K P E] = lgr(A,B,Q,R,N) in MATLAB. Chapter5: Chapter 5 compared with the Passive suspension through the applying MATLAB / Simulink simulation, according to the curve, we can prove that the optimal control of the active suspension make an improvement in performance such as the body acceleration and tire displacement, enhance the stability and of comfort of the project vehicles. And by simulating the valve-core displacement proves that the method is feasible.Chapter6: We have conclusions for the full text.The subject provided a good control method for enhancing the stability of project vehicles, comfort and off-road performance. It can ease the impact of road, attenuate load vibration, and it is helpful for running comfortably. However, as the theoretical study has not yet been tested, it still needs to conduct in-depth studies.