By using optimal design theory.and control inference. a new staged and multi- model control strategy is presented in this paper. By means of different control algorithms applies to different deviation angles|θ

e

|: minimal steep control for a large deviation angle

optimal PID control for a small one and when the system approaches its stable state.the ve- locity positive feedback is used on the base of optimal PID control. Simulation results show that the staged multimodel control has high tracking accuracy and the characteristic of fast tracking.