Abstract This paper presents and compares three fuzzy-based nonlinear control strategies: fuzzy PD controller (FPDC), sliding-mode PID (SMC-PID), and fuzzy sliding-mode controller (FSMC) for the altitude and attitude regulation of a six-degree-of-freedom (6-DOF) coaxial octorotor UAV. The proposed FSMC integrates a type-1 Mamdani fuzzy inference system in the switching law of SMC to suppress chattering while maintaining robustness and stability. A full 6-DOF dynamic model is used to evaluate controller’s performances under rectangular and circular trajectories, with and without external wind disturbances. Quantitative evaluation using ITAE, IAE, and control effort indices shows that FSMC achieves the lowest tracking error and energy consumption compared with FPDC and SMC-PID. The obtained results confirm that FSMC provides superior tracking accuracy, robustness, and energy efficiency, which makes it a promising approach for real-time UAV applications.
Toudji et al. (Sun,) studied this question.