Slow On-off Control of Two-state Damping for Electrically Controlled Air Suspension Based on Extended Kalman Filter

摘要

To improve riding performance of the bus with air suspension, the half-car nonlinear model of air suspension was created with the help of analyzing nonlinear character of spring-pneumatic. Slow on-off control of two-state damping was proposed according to the tire deformation and suspension deflection, and the shock absorber with two-state damping was designed by opening and closing the orifice of throttle. It was difficult to obtain the tire deformation directly, and the state-observer of air suspension was proposed based on Extended Kalman Filtering (EKF) algorithm, namely the tire deformation was estimated by the suspension deflection and its relative changing speed. Simulation shows EKF algorithm can estimate the running states well, and the estimating error of RMS is below 10% in 3 seconds and the whole vehicle testing validate that the slow on-off control can enhance the capability of air suspension.