Compound Control Methodology for a Robust Missile Autopilot Design

This paper considers the application of compound control method to high-performance autopilot design for aerodynamically controlled agile missiles. The control objective in this paper is to track a reference angle of attack command signal in the presence of external disturbance and aerodynamic coefficient uncertainty with desired performance. The external disturbances and the aerodynamic uncertain terms are first lumped together as the lumped uncertainties, which can be estimated accurately by the introduced extended state observer (ESO). Combining the sliding mode control (SMC) and backstepping techniques, a robust nonsmooth (but continuous) compound control law is developed for angle of attack tracking. With the aid of Lyapunov stability criteria, it is proven that the angle of attack tracking error will converge into a small neighborhood around the origin in finite time. Theoretical analysis and simulation results demonstrate the robustness and effectiveness of the proposed composite method.