Backstepping and sliding mode cascaded compound control for AC position servo system

Aiming at wide variations in loads and moment of inertia, large disturbed moment of a rocket launcher position servo system, a backstepping and sliding mode cascaded compound control method was present. The sliding mode variable structure controller of velocity loop and the backstepping controller of position loop were designed. The sliding mode control can restrain effects of parameter uncertainties and external disturbance, while the backstepping control asymptotic track the reference position signal of the controlled device. In order to obtain reference results for comparison with the designed cascaded compound controllers, the same system with PID controller was examined as well. The simulation results show that dynamic tracking performance of the system is significantly improved and the robustness to parameter variations and external disturbances can be obtained.