Application of Additive-State-Decomposition-Based Model-Compensation Controller in Compound Vertical Takeoff and Landing Unmanned Aircraft

The compound vertical take-off and landing (VTOL) unmanned aerial vehicle (UAV) is a complex nonlinear system characterized by strong coupling, high complexity, and sensitivity to external disturbances and model uncertainties. For a VTOL UAV, there are two main control modes: multi-rotor mode and fixed-wing mode. The completeness and accuracy of the control model should be considered; therefore, an observer is used to observe the model's uncertainty and external disturbances. Based on the idea of additive state decomposition (ASD), the high-order differentiator (HOD) and compensation function observer (CFO) are combined to design an ASD-based model compensation controller (ASD-MCC), which achieves tracking control for the primary system and stability control for the secondary system. The stability and convergence of the closed-loop system are proven. Using the complete model of the compound VTOL UAV, numerical simulations are conducted in MATLAB's Simulink platform to compare the proposed control algorithm with traditional PID control and model compensation control (MCC), verifying the superiority and effectiveness of the proposed algorithm.