Composite Robust Roll Autopilot Design with UDE Observer

The aerodynamic parameters of tactical missiles have a high-frequency nonlinear influenced by the varying angle-of-attack, altitude, and flight velocity during the phase of large span flight, which seriously impacts the roll channel stability of tactical missiles. In favor of input-output linearization (IOL) controller and uncertainty and disturbance estimation (UDE) technology, the system's nonlinearity can be regarded as a part of uncertainty, and an observer is designed to observe the output derivative of the system, which simplifies the requirements of the model. In addition, a method of actuator dynamic compensation is proposed after considering the second-order actuator in the design of roll autopilot. The roll autopilot designed based on IOL + UDE method has the robustness and the effectiveness of actuator dynamic compensation, which is proved in the simulation results.