Research On Modeling And Control Of Three-stage Vibration Reduction Active Suspension

With the growing development of technology,the automotive suspension technology is constantly improving,and the people’s requirements for the comfortability,stability and maneuverability of the car are also higher.Automotive active suspension can meet people’s requirements,the characteristics of the vehicle active suspension is to improve the smoothness of the vehicle,it can adjust the damping and rigidity of the vehicle suspension according to external factors in a timely manner,so that the vehicle is in the optimal vibration-damping state the highest ride comfort.Therefore,the improvement of vehicle ride comfort is the research hotspot of active suspensionIn this thesis,a three-stage vibration-damping active suspension is designed.The characteristics of the suspension are changed through the increase of vibration isolation.The dynamic model of the three-stage vibration-damping active suspension is established.Under the given random road excitation,the effects of vehicle acceleration,suspension dynamic disturbance and tire travel on the performance of the active suspension are analyzed,and the vehicle ride comfort evaluation index is proposed.we designed the quarter-car three-stage vibration-damping active suspension system as the research object,and used linear quadratic gaussian control strategy to simulate.The main research contents of this paper are as follows:(1)Design a three-stage damped active suspension structure and establish a dynamic model.Analyze the performance characteristics of the primary shock absorber and the secondary shock absorber active suspension,establish a first-order vibration-damping and two-stage vibration-damping active suspension model,and analyze the advantages and disadvantages of primary vibration reduction and secondary vibration reduction active suspension The three-stage vibration-damping active suspension structure is designed,and the three-stage vibration-damping active suspension dynamics model is established.Using the road roughness as the main external input of the vehicle system,the random road excitation is obtained.The effects of vehicle acceleration,suspension dynamic disturbance and tire travel on the performance of active suspension are analyzed,and the vehicle ride comfort evaluation index is proposed.The designed three-stage vibration-damping active suspension overcomes the shortcomings of large acceleration and large vibration power of the primary and secondary vibration-damping active suspensions.(2)The design of three-stage vibration-damping active suspension LQG controller.Firstly,the comprehensive performance index of suspension controlled by LQG is proposed,and the weighting coefficient of the comprehensive evaluation index of suspension is determined by using the analytic hierarchy process.Then LQG controller is designed based on the dynamic model of three-stage damping active suspension in chapter 3.At last,the first,second and third vibration damping active suspension controlled by LQG is simulated and analyzed by Matlab/Simulink software.(3)Comparative Analysis of Vehicle Active Suspension Simulation.The three-stage vibration-damping active suspension system is compared with the first-stage vibration-damping active suspension and the second-stage vibration-damping active suspension system.The suspension performance evaluation index decreased by 66.99%and 1.63%,respectively,and the body acceleration decreased by 56.81%and 14.03%respectively,explain that the LQG-controlled three-stage vibration-damping active suspension system designed in this paper can achieve better vehicle ride comfort.The vibration power of the suspension decreased by 44.61%and 31.57%respectively,it indicates that the vibration power of active suspension system will decrease with the increase of vibration isolation.