Design And Calibration Study On Vehicle Body Height Adjustment System Of ECAS Bus

With the improvement of people's requirement for the ride comfort and the development of suspension technique,the application of air suspension on automobiles are becoming increasingly widespread,meanwhile,with the application and popularization of the electronic system and the development of the vehicle control technology,the electric control system will gradually replace the traditional mechanical control system.It can be predicted that the application of the electronic control air suspension system to the vehicle will be more and more popular.The research on charging and deflation characteristics of height control system of ECAS bus and experimental study has been done in this paper.Firstly,the effective area,height and volume of the air spring are introduced. The non-linear elastic mathematical model of the air spring is build adapt to the thermodynamic basic theory.And the stiffness and frequency characteristics of air spring are analyzed.The characteristics of shock absorbers are introduced and the damping force and speed characteristic curve of the shock absorber are presented. The two running height of vehicle body and modularization of control strategy is designed.This can provide theoretical foundation for latter research.Secondly,the functional properties of the main components of electric control system are introduced.Based on fluid motion regulation of pneumatic circuit,the factors which effects speed of charging are discussed.And hence principles for components choice are provided.Subsequently,the process of charging and deflation of ECAS is discussed.For system can adjust height precisely,the mathematical model of height adjust system is derived according to vehicle dynamics theories.Thus simplified control and gearshift integral PID/WPM control are discussed and simulated.The results show that the control is effective.Finally,the adjustment and calibration system for ECU is developed by VB 6.0,and the control system of ECAS bus is calibrated.And meanwhile,the parameters of the system are set and sensors of the system are calibration.The road experiments of vehicle are processed using virtual measurement system.Through the analysis results,it showed that the electric control system can improve the ride comfort of the passenger car significantly.