Adaptive novel non-singular terminal sliding mode control for fixed-wing UAVs with compensation function observer

Abstract

To address the challenges of modeling inaccuracies, external unknown disturbances, and degraded tracking speed and precision in complex environments for fixed-wing unmanned aerial vehicles, this paper proposes a novel adaptive sliding mode controller based on a model compensation method. A high-precision compensating function observer is introduced to estimate and compensate for both model uncertainties and external disturbances in real time. To further enhance tracking performance in complex and dynamic conditions, a new composite reaching law is developed, and its gain parameters are adaptively tuned to ensure rapid control response while effectively suppressing chattering. To evaluate the control performance of the designed controller and its tracking capability in complex and dynamic environments, numerical simulations are conducted on the MATLAB/Simulink platform. Furthermore, hardware-in-the-loop experiments based on the RflySim platform are carried out for additional verification. The results demonstrate that the proposed control method effectively reduces system chattering, shortens convergence time, and enhances disturbance rejection capability.