Disturbance observer-based adaptive sliding mode control for variable dihedral and dual-mode yaw vectoring...

Area of Science:

• Robotics and Control Systems
• Aerospace Engineering
• Unmanned Aerial Vehicles (UAVs)

Background:

• Tricopter UAVs require advanced control for stability and maneuverability, especially with variable configurations.
• Existing control methods struggle with nonlinear dynamics and external disturbances like wind gusts.

Purpose of the Study:

• To propose and validate a novel Disturbance Observer-Based Adaptive Sliding Mode Control (DOB-ASMC) architecture for a tricopter UAV.
• To enhance attitude tracking, yaw performance, and robustness against disturbances in a UAV with variable dihedral arms and dual-mode yaw vectoring.

Main Methods:

• Developed a novel DOB-ASMC architecture integrating a nonlinear disturbance observer (NDO) and an adaptive sliding mode control law.
• Formulated the nonlinear six-degree-of-freedom (6-DOF) dynamics of the tricopter with reconfigurable dihedral arms.
• Performed Lyapunov stability analysis for finite-time convergence and tracking error boundedness.
• Conducted comprehensive simulations (MATLAB/Simulink) and hardware-in-loop (HIL) experiments.

Main Results:

• The DOB-ASMC demonstrated superior attitude tracking and robust yaw performance compared to PID, standard SMC, and backstepping controllers.
• Achieved up to 63% reduction in root mean square (RMS) tracking error and 47% attenuation in chattering under severe wind disturbances (8 m/s).
• Showcased graceful degradation in performance under challenging environmental conditions.

Conclusions:

• The proposed DOB-ASMC architecture offers significant improvements in UAV control, particularly for tricopters with complex configurations.
• The NDO effectively estimates and compensates for external disturbances, enhancing system robustness and stability.
• Experimental validation confirms the effectiveness of the DOB-ASMC for real-world UAV applications.