A new control design for a morphing UAV based on disturbance observer and command filtered backstepping techniques

Morphing unmanned aerial vehicle (UAV) can manipulate its shape for excellent flight performance under different conditions. The most research of the morphing UAV focuses on modeling. However, the issues including nonlinear characteristics, strong couplings, and mismatched disturbances are inevitable, which can lead to a great challenge in controller design. In this paper, a composite anti-disturbance controller is developed for morphing UAV to achieve enhanced flight performance under multiple sources of disturbances. In the inner loop, a nonlinear disturbance observer (DO) is constructed to estimate the inertial forces and moment; while in the outer loop, the command filtered backstepping (CFBS) method is adopted to guarantee the stability of the closed-loop system. The system outputs can promptly track reference signals in the morphing process of the UAV. The novelty is that the disturbance estimations are added into the control laws to compensate the mismatched disturbances. When comparing to the previous methods, the control scheme presented in this study can significantly improve the performance of anti-disturbance. Finally, the effectiveness of the proposed method is illustrated by numerical simulations.