Study On Fuzzy Control Strategy Of Vehicle Semi-active Suspension Based On Expert System

The main function of the suspension system is to buffer the impact load transmitted from the road surface to the vehicle body and attenuate the vibration to ensure the stability and ride comfort of the vehicle.In the existing suspension system,the semi-active suspension has a damping performance close to that of an active suspension,which has a low energy consumption,a simple structure,and a low cost,and is currently the main direction of research.In order to obtain the damping performance of the semi-active suspension under expert fuzzy control,this paper studies the aspects of road input,evaluation index,control method and control effect,and verifies the effectiveness of the control strategy.The main research contents and achievements are as follows:(1)In order to analyze the damping performance of the semi-active suspension more comprehensively,two kinds of road models with white noise random excitation and convex excitation of the deceleration belt are established.The influence of vehicle speed on road excitation is studied.Based on vehicle dynamics theory and the modern control theory,a7-DOF suspension model of the vehicle is built.Based on the output parameters of the suspension,a comprehensive evaluation index and evaluation principle of the suspension performance is designed by a weighted method.According to the output parameters of the suspension under the simulation of a random road,the comprehensive performance evaluation index of the suspension is designed by the weighted method,and corresponding evaluation principles are formulated.(2)Set up the simulation models of semi-active suspension system under two modes of vehicle independent control and coordinated control.Based on PID control theory,design two kinds of PID controllers for control mode,compare the vehicles in C-grade random road Independently control and coordinated control of the performance evaluation indicators of the suspension,the results show that,the effect of improving the vehicle ride comfort under the two control modes is not significant,but the vehicle coordination control has more independent control over the vehicle ride comfort and control stability Significantimprovement.(3)Based on the theory of fuzzy control and expert control,and the semi-active suspension system simulation models based on fuzzy control and expert control strategy are established.The simulation is carried out under the B level random road and the convex road of the deceleration belt.The results show that under both road,the comprehensive performance of the semi-active suspension system is obviously better than the passive suspension.The control effect of the expert fuzzy controller is better than the fuzzy controller.Further,the virtual prototype of the vehicle is set up by Adams/Car software,which is introduced into the Matlab/Simulink,and the model of the expert fuzzy control suspension system is built,and the joint simulation is carried out under the random road to verify the effectiveness of expert fuzzy control strategy for improving the suspension performance.