Design of a Three-Loop Overload Autopilot for STT-Guided Munitions Based on a Fuzzy Compensation Extended State Observer

During flight, guided munitions operate in severe cross‑domain aerodynamic environments and are subjected to external disturbances, which induce strong nonlinearities and model uncertainties that significantly degrade the control performance and robustness of the autopilot. Focusing on the combined requirements of high dynamic responsiveness and strong disturbance rejection for the three‑loop overload autopilot of skid‑to‑turn (STT) guided munitions, this paper introduces fuzzy logic into the linear active disturbance rejection control (LADRC) framework, proposes a fuzzy‑compensated extended state observer (FC‑ESO), and develops a three‑loop FC‑LADRC overload autopilot structure. Based on the traditional linear extended state observer (LESO), a multi‑channel fuzzy compensation mechanism is incorporated to achieve dual regulation of “parameter adaptation + real‑time estimate correction,” thereby effectively enhancing the dynamic disturbance estimation accuracy and noise suppression capability of the observer under severe aerodynamic parameter perturbations and strong noise. Using Lyapunov stability theory, the input‑to‑state stability (ISS) of the FC‑ESO error system is analyzed, and sufficient conditions for boundedness are derived, providing theoretical support for the stable application of the fuzzy‑compensated ESO. Comparative simulations with conventional controllers are then conducted to quantitatively evaluate the proposed method in terms of control signal quality, dynamic response, disturbance attenuation, and full‑trajectory robustness. The results demonstrate that, under wide‑range aerodynamic parameter variations and significant external disturbances, the proposed controller outperforms the benchmark methods in tracking accuracy, response speed, and disturbance‑rejection robustness, thereby significantly enhancing the overall control performance of the three‑loop overload autopilot for STT-guided munitions.