LuGre Model-based Longitudinal Ride Comfort Control of Vehicle during the Post-braking Phase

This paper deconstructs the braking process of the vehicle and points out the importance of vehicle ride comfort in the post-braking phase. The vehicle state equation based on LuGre tire model in the post-braking phase is obtained, which is an under-actuated system with highly nonlinearity and parameter uncertainty that impede controlled the direct use of general controllers. Therefore, a sliding mode observer based on LuGre tire model is established. The nonlinear characteristics, effect of vertical dynamics and parameter uncertainty of the system are all reflected in the designed sliding mode, realizing the simplification of the state equation and the asymptotic stabilization of the state estimation error. For the simplified system state equation, this paper proposes a dynamic compensation sliding mode controller based on linear matrix inequality to improve the vehicle ride comfort in the post-braking phase through brake pressure regulation. The control trigger conditions, brake pressure recovery conditions and decompression limits are also designed for further improvement. The observer and controller are simulated and verified in MATLAB / Simulink, which shows that the longitudinal ride comfort in the post-braking phase is significantly improved.