Research On Fuzzy Control Strategy Of Automobile Active Suspension

With the development of automotive technology and the increasing demand for ride comfort,more and more attention has been paid to the active suspension,which can adjust body posture according to road input and body state variable.At present,because the damping coefficient and stiffness coefficient can not be changed,passive suspension can hardly satisfy people’s driving needs under complex road conditions.Compared with the passive suspension,the active suspension has superior comprehensive performance.It can adjust the vehicle posture in real time according to the road input and vehicle body state,so that the suspension is in the optimal state of vibration reduction.The effect of the suspension control strategy have a direct impact on the performance of the active suspension.Therefore,the research and promotion of active suspension system has gradually attracted the attention of people.In this paper,on the basis of related research about active suspension at home and abroad,it carried out the research work on the suspension fuzzy control strategy,including the establishment of road surface model and passive suspension model,design of active suspension fuzzy controller,application of adaptive genetic algorithm and variable domain theory to optimize the traditional fuzzy control method.Then set up a Simulink simulation model for off-line simulation,and build a hardware-in-the-loop test bench for hardware-in-the-loop simulation based on Veristand.It has a theoretical and practical significance for Implementing fuzzy control on active suspensionFirstly,the nonlinear characteristics of the suspension spring was taken into consideration,this paper established the mathematical model of four degree of freedom active suspension.Random road input model and impact road input model were built in consideration of the controller design and simulation analysis,as well as the performance evaluation index for vehicle.on the Basis of fuzzy control theory,fuzzy controller was designed.By analyzing the advantages and disadvantages of traditional fuzzy control,this paper put forward two kinds of optimization methods,namely adaptive genetic algorithm fuzzy PID control strategy and the variable universe fuzzy control strategy,and then modeled the controller.Then Matlab/Simulink software was used to establish the model of road and suspension and analyze the riding comfort and stability of vehicle with active suspension and passive suspension under different road condition.The simulation results show that the active suspension can effectively restrain the vibration of vehicle,improve ride comfort and stability and the control strategy which was optimized has a more significant control effect.Meanwhile the influence of vehicle parameter perturbation on controller stability is also analyzed.The results show that the active suspension has better robustness.Finally,in order to verify the practicability of the control strategy,we used Matlab/Simulink,Matlab/RTW,Veristand and other software to integrate the data acquisition card,microcomputer and active suspension electronic control unit,and design the hardware in the loop test bench for the active suspension.