Analysis on Stability of Three-loop Autopilot with An Acceleration Feedback Augmentation Loop

In order to construct a stable augmentation loop, a novel three-loop autopilot structure with an acceleration feedback is proposed. Based on LQR and analytical methods, the design process of the controller parameters is deduced. For a static unstable missile, the control characteristics of a three-loop autopilot with acceleration feedback are compared with classical three-loop and pseudo-angle-of-attack feedback three-loop autopilots. It is pointed out that the closed-loop gain of the three-loop autopilot with acceleration signal feedback is 1, which is not affected by the control parameters. The autopilot can control the static unstable missile, and the acceleration signal is easier to obtain than the pseudo-angle-of-attack.