Study On Fuzzy Control Of A Semi-active Vehicle Suspension

The ride comfort and handling stability of the automobile have close relationship with the suspension system. As structure parameters of traditional passive suspension can not adaptively change with external conditions, the improvement of dynamic performance, is very difficult. However, structure parameters of semi-active suspension, such as damping, spring stiffness and so on, are adjustable, which can serve the needs much better. At the same time, compared with active suspension, the semi-active suspension has simple structure and low price, so it is regarded highly and widely.In the paper, a nonlinear suspension model of four-degree freedom is set up. Under certain input signals, the control laws of fuzzy controller are adjusted by using different weight coefficients and Matlab software is used to simulate the performances. At the same time, another fuzzy control method based on genetic algorithm is introduced and applied to the control of semi-active suspension, and the genetic algorithm is also used to optimize the fuzzy control laws. Then, the results are compared and the performances are analyzed between passive suspension and semi-active suspension with different control methods. The results show the fuzzy controller can clearly reduce the vibration and improve the ride performance. At last, the real experiment with semi-active and passive suspensions are carried out and the results prove that the mathematic model is correct, and the control strategy is practical.