Stability Analysis of Electronically Controlled Air Suspension Ride Height System Based on Center Manifold Method

To analyze the stability of ECAS ride height system, a coupled model of gas thermodynamics and vehicle dynamics is established with consideration of the system nonlinearity. By using the center manifold method to reduce the dimensionality of the ride height system, the flow equation of the center manifold is solved. Calculating results show that the stability of the ride height system is related to the one degree term and quadratic term of the nonlinear damping coefficient of the shock absorber. Based on the polynomial fitting, the approximate analytical calculation of amplitude-frequent characteristics of the nonlinear ride height system is obtained. The simulation results show that the nonlinear stiffness and damping affect the amplitude jump and the nonlinear parameters should be considered during the design of the control system. Thus, this paper presents a solution for the stability control algorithm of the ride height system.