Abstract—The characteristics of nonminimum phase and static unstable of a tail controlled tactical missile are presented firstly. Then, in order to eliminate the static error, a cascade PI compensator was introduced to the classic two loop autopilot. Due to the slow tracking for command acceleration, the longitudinal three-loop autopilot design is driven based on LTI model of missile plant to stabilize the nonminimum phase static unstably missile airframe. The focus is to explain the performance and the control effect at different values of velocity and stability derivative 〖(M〗_α) of two algorithms on missile plant. The analysis is executed by establishing a standard algorithm in virtue of MATLAB/Simulink for autopilot design. The simulation results indicated that three-loop topology gives better tracking than two-loop with a cascade PI compensator at different value of stability derivative M_α. On the other hand, two-loop has a better response and less control effort at different velocities. fin angle and fin angle rate are less than the three loop for static unstable and stable missile.

Index Terms—PI compensator, two loop autopilot, three loop autopilot, flight control system, missile.

The authors are with the School of Automation Science and Electrical Engineering, Beihang University BUAA), Beijing 100191, China.

Cite:Emad Mahrous Mohamed, Lin Yan, "Design and Comparison of Two-Loop with PI and Three-Loop Autopilot for Static Unstable Missile," International Journal of Computer and Electrical Engineering vol. 8, no. 1, pp. 1-11, 2016.