| The off-road vehicle is an especial vehicle, the jumpiness of its suspension is very big and the damping and nonlinearity is obvious. So, we hope that the suspension off-road vehicle not only can be lower, but also make automobile possess handing stability and ride comfort when it runs along straight line, speed up, breaks and turn, and can improve the pass ability. From those years, the technology of off-road vehicle is handed by the corporation of America and Europe. The development of suspension system of off-road vehicle is mature in foreign country. However, the study on the suspension system of off-road vehicle in our country is concentrated on the hydro-pneumatic suspension, and mainly on the hy-pneumatic spring. There are not any others products in the market.This dissertation bases on the research of"2.11"of Jilin University. This project intends to develops one kind of SUV that is possible the multi wheel individual drive, controlled by the microcomputer battery solution proportional, and the multi wheel has the independent ground adaptive control and to be hanging all-terrain vehicle on own initiative. Its six independent suspension expansion can the wide degree. My job is to proposes one kind of brand-new suspension system that controlled by the computer battery proportional the hydraulic cylinder as functional element's mountainous region all-terrain vehicle's suspension system, mainly through studies and summarizes the domestic and foreign related suspension forks and the control technology present situation. This system can carry on the automobile body altitude mixture control besides enhance the automobile body and can maintain it. When travel, this suspension system can guarantee that the automatically six driving gears contact with the ground reliably, make sure each wheel have a more balanced force of traction at times, enables the vehicles to have the good smoothness,the operation stability. Therefore, vehicles' cross-country performance will be improved mostly.I designed suspension`s the hydraulic system according to the pursues perfect pass performance. Using the suspension system's design parameter and the technical specification of this SUV, I have determined hydraulic system's discharge head as well as hydraulic cylinder's main parameter. By studied the electro-hydraulic servo valve type and the principle introduction, I has chosen the battery solution proportion. In the suspension fork control system, I chooses the simple PC control system that is easy to program, for carries on the experiment in the product development stage to each kind of suspension fork control algorithm. I took the VB senior language as the software programming language, and has chosen the data acquisition card and the displacement, the pressure transmitter. The whole SUV weight is certain, so , when one wheel`s load changes, the others would change accordingly. That will lead to all hydraulic cylinder move. So, I define that the moving one is the change mostly one. That can prove the whole suspension keep balance.The strength from hydraulic cylinder exert on the SUV, so, I consider the driver part in the process of modeling. The mathematical model for active suspension system of SUV is established. The input is voltage from PC and the output is the strength in the model. I defined the load current capacity and load pressure. In the model, asymmetrical valve control asymmetrical hydraulic cylinder.Through the simulation of single-wheel suspension pressure control system using Matlab, this control system could get the proper stable contact pressure between type and ground which are see ked of this design. For manual modulate highly control system, the simulation result displayed the suspension with good reflection, correct location, could get the requirement.During hardware circuit designing, this paper adopted as more as generally used circuit. Considering the power was less stability, researched proportion amplifier control of proportion commentator. Controlling the power voltage usually changed with the load and temperature's change, it necessary to keep voltage stable with voltage-stabilizer circuit. I designed the PWM for power amplification part. It is a energy conservation circuit. The proportional amplifier control the electric current in the Electro-magnet by changed the PWM, so it can decide the position of electro-hydraulic servo valve. I designed the others electric part, make sure that proportional amplifier can fill the need of electro-hydraulic servo valve.
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