The importance effect of the undamped natural frequency to the autopilot: Study on the two-loop acceleration autopilot

In order to design a satisfactory response autopilot for a rear controlled missile, the method of pole placement is used. To make sure the autopilot have enough stabilizing margin, a fixed damping of this autopilot assumed. The autopilot performs tremendous difference which lies on the relative relation of the undamped natural frequency of the autopilot and the weathercock frequency. The results show that the undamped natural frequency of the autopilot must large than the weathercock frequency. Without any compensation, the two-loop autopilot will result in enormous steady error even if the undamped natural frequency is large enough.