Abstract: The modeling of the existing air spring system is complex, and it is easy to produce oscillation in the process of height control of the air spring system. In view of these problems, a thermodynamic air spring modeling method and an air spring high degree control strategy based on proportional-integral-differential (PID) were proposed. Firstly, the air spring system was taken as the research object, and the method of thermodynamic analysis was adopted to establish a high-precision nonlinear empty spring model with temperature and pressure as independent variables. Then, the PID control strategy of air spring height was designed, and the above system model was verified: the mass flow G was taken as the input of the PID control system, and the vertical model feedback of the vehicle body height and other state variables were taken as the output of the control system. Finally, the no PID control strategy and PID control strategy were simulated and compared by MATLAB/Simulink under different working conditions. The results show that the established thermodynamic empty spring model can effectively reflect the dynamic characteristics of the empty spring system, and the improvement rate of RMSE in the control process is up to 34.1% compared with the PID controller, which improves the control accuracy, reduces the oscillation in the height control process, which is of great significance in practical application.

Key words: air spring;thermodynamic analysis;height control;air suspension;proportional-integral-derivative (PID) control

LI Zi-xuan, WU Ming-yu, ZHOU Fu-qiang, et al. Modeling of air spring and its height control strategy［J］.Journal of Mechanical & Electrical Engineering, 2022,39(1):53-58.