Higher order sliding mode and adaptive backstepping controllers for a full-car model with active suspension

The robust stabilization of the vertical position, pitch and roll dynamics of the center of gravity for a vehicle with active suspension is addressed in this work. Three different higher order sliding mode (HOSM) control algorithms and an adaptive backstepping controller (ABC) are designed to fulfill the control objective. First, two second order sliding mode controllers, the quasi-continuous and the nested, are designed to stabilize the 2-relative degree vertical position. Then, a super-twisting (ST) algorithm is designed, by means of a 1-relative degree sliding function, obtaining asymptotic stability. For the ABC, adaptive parameters dynamics are proposed, as well as the control law that adds desired linear dynamics. Finally, a performance comparison between the proposed controllers is presented based on simulations results.