Nominal Model-Based Sliding Mode Control with Backstepping for 3-Axis Flight Table

Based on nominal model, a novel global sliding mode controller (GSMC) with a new control scheme is proposal for a practical uncertain servo system. This control scheme consists of two combined controllers. One is the global sliding mode controller for practical plant, the other is the integral backstepping controller for nominal model. Modeling error between practical plant and nominal model is used to design GSMC. The steady-state control accuracy can be guaranteed by the integral backstepping control law, and the global robustness can be obtained by GSMC. The stability of the proposed controller is proved according to the Lyapunov approach. The simulation results both of sine signal and step signal tracking for 3 axis flight table are investigated to show good position tracking performance and high rcr bustness with respect to large and parameter changes over all the response time.