LQR force command planning–based sliding mode control for active suspension system

In this article, a linear quadratic regulator (LQR)-based sliding model control strategy was proposed for the commercial vehicle seat suspension system. First, the multiple degrees of freedom mechanical dynamics model of a quarter suspension system was built. Then, the LQR force command planner was designed based on mechanical dynamics to ensure driver comfort. Second, considering the mechanical dynamics augmented with hydraulic actuator dynamics, a proportional-integral sliding mode control strategy was developed to track the reference force, which was calculated by the LQR force command planner in real time. Taking the problems of noise disturbances and unavailable full states feedback into consideration, the Kalman filter and tracking differentiator were designed and integrated into the control algorithm. Finally, the quarter suspension AMESim model was built, and the proposed control strategy was implemented and verified in the AMESim-Matlab/Simulink co-simulation environment. Comprehensive simulations were carried out. The simulation results, both from time domain and frequency domain perspective, indicated that the seat ride comfort can be effectively improved with the proposed method.