Three-loop autopilot design and simulation

In order to realize missile real-time change flight trajectory, three-loop autopilot is setting up. The structure characteristics, autopilot model, and control parameters design method were researched. Firstly, this paper introduced the 11th order three-loop autopilot model. With the principle of systems reduce model order, the 5^th order model was deduced. On that basis, open-loop frequency characteristic and closed-loop frequency characteristic were analyzed. The variables of velocity ratio, dynamic pressure ratio and elevator efficiency ratio were leading to correct system nonlinear. And then autopilot gains design method were induced. System flight simulations were done, and result shows that autopilot gains played a good job in the flight trajectory, autopilot satisfied the flight index.