Research On Control Method Of Semi-Active Suspension With Solenoid Valve Damper Under Discrete Impact Road Conditions

Recently,the continuously adjustable solenoid value damper has become a research hotspot in the fields of semi-suspension,because of its close structure,reliable performance and simple control method.However,there are still some shortcomings.The one is that solenoid value damper has poor model precision due to the complex internal structure.Another is that a single control method can't match actual complex road condition.Beginning from the problems,this paper analyzes the internal structure and working process of solenoid value damper.Then,mathematic model of damper is established.For discrete impact road surface,a switching control strategy is designed between the Sky-hook and the Ground-hook based on the mathematic model.The effectiveness of the control method is verified by simulating with high precision vehicle dynamics model.Finally,this paper completes the hardware design of experimental signals from bench test,which can improve the quarter semi-active suspension experimental environment,and prepare the hardware conditions for the validation of the model and control methods.Firstly,this paper analyzes the internal structure and working process of solenoid value damper.The hydraulic models and mathematic models of internal valves are established in this paper.Then,according to the theory of fluid mechanics,its mathematic model of rebound stroke and compress stroke is established.Finally,the damping characteristic curve of the damper is obtained by simulation with MATLAB program.Comparing and analyzing the characteristics of the damping characteristics of the solenoid valve damper and the magneto-rheological damper.The model provides a reference for the design of subsequent control strategy.For discrete impact road surface,the vibration characteristics of the spring mass is different when the vehicle is driving on and off the bump road.Therefore,suspension control system requires different performance when the vehicle is driving on the different road.This paper explores the identification method of discrete impact road,and provides vehicle-road coupling excitation information for different control methods.This paper put forward a method for road surface identification in real time by calculating the instantaneous frequency of dynamic travel.The reliability of the identify method is verified by the simulation with single bump road and continuous bumps road.The spring mass is vibrating under the vehicle-road coupled transient excitation when vehicle is driving on the bump road.The spring mass is vibrating without the vehicle-road coupled transient excitation when vehicle is driving off the bump road.Through simulation analysis in time domain and frequency domain,the Sky-hook and Ground-hook have their respective advantages under two working conditions.This paper designs a switching control strategy according to the applicable conditions of Sky-hook and Ground-hook.The identify result of road determines the switching points.The simulation results of high precision vehicle dynamics model show that the switching control strategy can integrate the control effect of Shy-hook and Ground-hook and improve the comfort performance.For further verification of the performance of the switching control strategy in the actual work conditions,this paper designs the hardware interface board for signals based on the test bench of electro-hydraulic damper.This paper completes the test of the signal processing system,which can improve the experimental environment of the semi-active suspension and prepare the hardware conditions for the subsequent bench tests and verification.