Research Of Fuzzy PID Control Of Vehicle Semi-active Suspension

With the development of automobile industry, the ride comfort and handling performance of vehicle become increasingly important. As structure parameters of traditional passive suspension can not adaptively change with external road and real-time conditions, it limits the improvement of dynamic performance. However, the semi-active suspension can not only overcome the shortcomings which the stiffness and damping of passive suspension is constant, but also has similar damping performance compared with active suspension. At the same time, the semi-active suspension has simple structure, low price and less energy consumption, so it receives the comprehensive attention in the fields of academe and industry.First of all, fuzzy control and PID control strategies are introduced briefly. For semi-active control of vehicle vibration, the seven degrees of freedom vehicle model is established to reflect the vehicle vertical vibration, pitch and roll vibration. Taking into account the road disturbance input on the impact of suspension control, according to real road conditions, a suitable road surface model is established.Secondly, in the foundation of knowing the fuzzy control strategy, the Fuzzy controller is designed for the semi-active suspension. Using the Matlab/Simulink, we simulated the passive suspension and the semi-active suspension system with fuzzy control strategy. The results show that the semi-active suspension system with fuzzy control strategy can effectively improve the ride comfort and handling performance.In order to further improve the performance of suspension, combining the advantages of fuzzy control and PID control strategy, a fuzzy PID controller is designed for semi-active suspension. The genetic algorithm is used to design the quantified factors of the fuzzy controller and the three correction factors of the PID. Compared with the semi-active suspension with fuzzy control strategy and passive suspension, the results show the semi-active suspension with fuzzy PID controller via genetic algorithm can improve the ride comfort and handling performance much better.