The Research On Modeling,simulation And Experiment For The Valve-controlled Continuously Adjustable Shock Absorber Of Passenger Car

With the rapid development of the automotive industry,people have put forward higher requirements for the ride performance and handling stability.The adjustable damping shock absorber can solve the contradiction between the ride performance and stability of the passive shock absorber.At present,there are relatively few studies on continuously adjustable shock absorbers in China.In this thesis,the valve-controlled continuously adjustable shock absorber of a passenger car semi-active suspension is taken as the research object to establish mathematical model of damping force and multi-domain simulation model,which based on analyzing the coupling mechanism between pilot valve and relief valve in the structure of the solenoid valve.Meanwhile,considering the response delay problem of the shock absorber based on typical road conditions,the preview control method of the semi-active suspension according to machine vision is studied.The feasibility and reliability of the simulation model and the control method are verified through the bench test and the vehicle road test.Thereby,a basis for the development and design of continuously adjustable shock absorbers and their application in real vehicles is provided.The main contents are as follows:1.The structural characteristic and working principle of the valve-controlled continuously adjustable shock absorber is analyzed.Then,the vibration model of the suspension system and the mathematical model of the shock absorber considering coupling relationship of the internal valve system are established.Lastly,the "machine-electric-liquid-gas" coupled simulation model of the valve-controlled continuously adjustable shock absorber is established by using AMESim.2.The performance of the valve-controlled continuously adjustable shock absorber is tested.Under different working conditions,the experiments of damping force indicator characteristics and velocity characteristics is conducted through the MTS electro-hydraulic servo performance test bench,which is to verify the damping characteristics of the shock absorber under various currents as well as the simulation model established above.The influence of several key design parameters,such as damping orifice,preload force and constant throttle orifice,on the damping characteristics is studied through the simulation model,which provides a theoretical basis for the improvement of shock absorbers.3.The preview control method of semi-active suspension based on the suspension system vibration model and machine vision is proposed,which is suitable for the dynamic characteristics of the continuously adjustable shock absorber.This method uses image processing to determine the deterministic excitation of the typical road conditions ahead,and the real-time information of the vehicle is fused to adjust the damping force of the valve-controlled continuously adjustable shock absorber in advance.By this way,the problem of the response delay of the shock absorber under instantaneous deterministic excitation is solved.4.The vehicle road test is used to verify the feasibility and effectiveness of the preview control method.The test results show that the valve-controlled continuously adjustable shock absorber under the preview control method has greater ride performance for the vehicle.Compared with before,the reduction of the maximum excitation energy improved almost 30% under the typical road condition.The study provides a theoretical basis for the engineering practice of continuously adjustable shock absorbers.