Designment And Study Of Semi-active Suspension Controller Based On Large-scale System Theory

Suspension system is the important vehicle part to improve the ride comfort and safety of vehicle. Conventional passive suspension has great limitation in harmonizing the two main performance indexes of vehicle. Recently, researches on electronic controlled suspension are developing, in order to improve the complex performance of vehicle suspension. Though active suspension can remedy the defects of traditional suspension system, it has not been widely applied heretofore, owing to its high cost in manufacture and operating. However, semi-active suspension not only can remedy the defects of traditional suspension system but also reduce the cost. Therefore, semi-active suspension has high research value as well better prospect in application. However, former studies about semi-active suspension are mostly based on the 1/4 suspension model, which can just improve local performance of vehicle. Although a minority researches are based on the whole model, they usually bring problems as high ladder of the control matrix, large calculating time delay, ill harmonization, low stability and so on, so that embarrass the popularizing of semi-active suspension. Combining large scale system and smart control, further researches about the control system of semi-active suspension were going to be talked about.Firstly, considering the need of the control system of semi-active suspension, an ARM LPC2138 microcontroller was adopted as the core component of the hardware of the controller and the related peripheral circuit of the hardware was designed. The control unit was able to realize real-time data/signal acquisition and system control. The rotation angle and direction of electric machinery could be determined by the obtained data, and so the damping coefficient of the damper was regulated, the riding comfort and handling stability could be improved.Secondly, using the large scale system hierarchical theory, the control system of the whole semi-active suspension was designed while the control of four sub-systems was settled by the use of the fuzzy neural network. According the strategy discussed above, the software program, which was divided into the realization of control strategy and the acquisition & control of data/signal, was developed in modular.Finally, the road test was done by installing the controller in the testing vehicle. According to the result of test, the thesis analyzed the rationality of the semi-active suspension controller, validated the feasibility of the design method, and provided credible foundation for setting up more applicable semi-active suspension controller. Furthermore, the thesis analyzed the problems existing in the design, which provided a basis for further study and perfect semi-active suspension controller.