Fuzzy PID Control Of Air Suspension Optimized By Genetic Algorithm

Suspension system is the key component of vehicle ride comfort and comfort,which can mitigate the impact caused by the road roughness on the vehicle and attenuates vibration.Compared with the traditional suspension system,the air suspension takes the air spring as the elastic element and has the advantages of adjustable stiffness and low natural vibration frequency,which can effectively improve the comfort and ride comfort of the vehicle.In addition,the development momentum of new energy vehicles is rapid.As a key component of lightweight and green environmental protection,air suspension is expected to become the mainstream suspension system of future automobile suspension.In order to further improve the performance of air suspension,suspension control strategy can be used.Conventional fuzzy PID control has great subjectivity and blindness in parameter setting,so it is difficult to achieve the best system performance.In this paper,the genetic algorithm and fuzzy PID control are combined,and the fuzzy PID air suspension control strategy optimized by genetic algorithm is proposed.The related theory,controller and control strategy are studied.Firstly,the composition and elastic principle of air spring,the composition structure,working principle and performance advantages of air suspension system are described,and the mathematical model of 2-DOF 1 / 4 automobile suspension is established.In MATLAB,the road excitation model is established as the external input of the air suspension system,and the corresponding time-domain response curve is obtained;on the basis of the mathematical model,the Simulink simulation model of the air suspension is established;the performance evaluation indexes of the air suspension system are discussed.Secondly,in order to study the rationality and effectiveness of the air suspension model,a suspension test-bed is designed and built for relevant tests.The air suspension is excited by the excitation system,and the parameter setting is the same as the simulation.The response curves of air suspension simulation and test are basically consistent,and the trend is the same.The correctness and feasibility of the air suspension model are proved,and the simulation results have certain reference significance for the analysis of active control strategy of air suspension.Thirdly,based on the basic knowledge of fuzzy control and PID control,the corresponding PID controller and fuzzy PID controller are designed.Then the relevant theory of genetic algorithm(GA)is studied.In MATLAB software,the relevant genetic algorithm program is written to optimize the selection of fuzzy PID controller parameters and complete the design of GA Fuzzy PID controller.In Matlab / Simulink,three different controllers are established to implement different air suspension control strategies,and the corresponding time-domain response curve of air suspension system is obtained by simulation.The control effect of fuzzy PID of air suspension before and after genetic algorithm optimization is compared.The analysis shows that the performance of the air suspension system after applying the control strategy is better than that before applying the control strategy.In contrast,the fuzzy PID control optimized by genetic algorithm has better evaluation index value of air suspension,and the root mean square value of body acceleration,suspension dynamic travel and wheel dynamic load of suspension system is further reduced,so the control effect is better,which solves the limitation of traditional fuzzy PID parameter tuning and reflects the superiority of fuzzy PID control strategy optimized by genetic algorithm It provides a reference for optimizing the active control of air suspension.