Sliding mode control of air suspension with auxiliary chamber subject to system disturbance

In this paper, a sliding mode control of air suspension with auxiliary chamber subject to system disturbance is proposed for perturbation factors such as nonlinear variation of stiffness damping in air suspension systems, aiming to improve the suspension performance during operation of commercial vehicles. Combine thermodynamics and suspension dynamics theory to establish nonlinear model of the air suspension with auxiliary chamber, consider the nonlinear stiffness and damping of the air spring, and sensor noise and other disturbances, and establish the system state space equations. The nonlinear disturbance observer is designed to estimate the disturbance force and noise disturbance in the system, and the sliding mode controller is designed to calculate the desired control damping force according to the disturbance estimation value. Finally, numerical simulations of the air suspension control system considering the nonlinear force variation of the air spring and external disturbances are carried out on simulated road surface and real road surface data. The results show that the proposed control strategy has strong robustness to the system external disturbance variations, which is conducive to improving the smoothness of the vehicle.