Integrated Control Design For The Active Suspension System Based On Intelligent Control

With the development of society and the improvement of people's standard of living,people need better quality about the automobile,such as comfort,riding stability ,which is very difficult for the traditional passive suspension whose parameters have been fixed by optimization to adjust them to improve on the ride comfort.As one of the most important parts of a vehicle,suspension system plays a vital role in determining the dynamic behaviors of the vehicle.Active vehicle suspensions can improve ride comfort and provide good road handling,which makes better performance than traditional passive suspensions.Recently researches on vehicle suspensions have been gaining increased attentions at home and abroad,and it has become the advanced subject in the field of vehicle dynamics and control.A key task in designing an active suspension is to look for appropriate control laws which can provide satisfactory vehicle performance.Automobile suspension is a complicated nonlinear system,But groovy control methods take on certain limits because the optimum performance of suspension would not achieved if regular linear controlling was applied to the nonlinear system.So more efficient control polices are required to control the active suspension more practically and more effectively.But fuzzy control can apply to a complicated nonlinear and time- varying system.It can also satisfy more serious requests and be fit to more uncertain environment than regular adaptive systems.So the research of the application of fuzzy control in automobile active suspension spreads out in the article.In this dissertation nonlinear fuzzy control method in allusion to active suspension is investigated based on its characters to carry on research simulation. This research project intends to make all appropriate control system for vehicle Active suspensions based on analyzing the performances of vehicle and suspension system.In this paper,suspensions mathematical model of a quarter car with two degrees of freedom and read model are established,and then the state equation of suspensions model deduced. Considering the influence of the input disturbance, a mathematical description of road surface irregularity is established, which is the model of integral white noise.Based on the established active suspension model,the fuzzy controller of active suspension were designed by the theory of fuzzy.In the paper,the control laws of fuzzy controller are adjusted by using different weight coefficients and matlab is used to simulate the performance. weight coefficients and matlab software is used to simulate the performances.What is more, other fuzzy control methods based on genetic algorithm and LMS self-adaptived algorithm are introduced and applied to fuzzy control of active suspension, they are used to optimize the fuzzy control law. At the last, the results are compared between passive suspension and active suspension with different control methods. The results prove the active suspension ,compared with the passive suspension can obviously improve the comfort compared with the passive suspension on the performances of bus acceleration,at the same time, the simulation results also prove that the control strategy of fuzzy gives the best effectiveness.This paper can provide theory and numerical reference for the testing research and product development of active suspension.