Optimized adaptive fractional-order sliding mode control for quadrotor trajectory tracking under external...

In this article, an advanced nonlinear control strategy is proposed to address the trajectory tracking problem of a quadrotor under external disturbances. The controller is formulated as an Adaptive Fractional-Order Sliding Mode Controller (AFOSMC), which employs a super-twisting reaching law to achieve robust tracking, while an adaptive barrier function is incorporated to alleviate the effects of control signal saturation. In addition, the conventional discontinuous signum function is replaced with a smooth saturation function to effectively mitigate the chattering phenomenon. To further strengthen the performance of AFOSMC, ant colony optimization is used for tuning the controller gain parameters. The quadrotor dynamics are derived using the Euler-Lagrange formulation, providing a rigorous basis for controller design. Lyapunov-based analysis is conducted to verify system stability, ensuring reliable operation under varying conditions. Additionally, stochastic noise is incorporated into the quadrotor model to investigate the proposed controller's robustness. The proposed strategy is evaluated via numerical simulations, while its practical applicability is further assessed using controller-in-the-loop experiments. The obtained findings indicate that AFOSMC provides improved tracking precision while maintaining robustness and smooth control action.