Robust H∞ autopilot design for agile missile with time-varying parameters

This paper considers two autopilot designs using H_∞ loop shaping for an agile missile that experiences high angle of attack, highly nonlinear and rapidly changing dynamics, and aerodynamic variation after launch. The main autopilot design is started with two H_∞ control designs intended to cover the low-speed and high-speed regions of the flight envelope. Then, the two control designs are combined (via Mach variation) to construct a global controller that covers the entire flight envelope. The proposed autopilots have a simple structure and require no time-consuming gain scheduling for many flight conditions, while providing satisfactory tracking and robustness over the entire flight envelope. The performance of the designed autopilots is checked via a comparison study and a challenging intercept scenario. These performance test results clearly demonstrate the merit of the proposed designs.