abstract
- This study introduces an adaptive restricted controller designed to address the trajectory-tracking challenge encountered by an autonomous quadrotor aerial vehicle navigating through confined spaces. While existing methods often overlook the explicit enforcement of state constraints or rely on conservative approximations, this work aims to address that gap through a more direct and adaptive strategy. The quadrotor dynamics are represented mathematically using quaternions, facilitating the development of the adaptive control strategy. The proposed controller incorporates an adaptive state-dependent gain to regulate the quadrotor's motion within permissible airspace. Utilizing a gain auto-tuning approach, the controller ensures convergence of the quadrotor trajectory to a predefined reference trajectory, effectively managing both the position and orientation of the vehicle under quaternion dynamics. The control design integrates a direct barrier control Lyapunov function, explicitly considering state restrictions. This function validates convergence to the reference trajectory and derives the necessary state-dependent gains for the adaptive controller. Numerical evaluations demonstrate the efficacy of the proposed adaptive controller in achieving improved tracking accuracy and constraint satisfaction compared to conventional state feedback controllers. Furthermore, the controller ensures compliance with full-state restrictions, offering a promising solution for real-world applications. Experimental validation in a setup with predefined state restrictions further confirms the effectiveness of the proposed approach, exhibiting consistent tracking improvements and safe operation near constraint boundaries over the proprietary controller installed in the quadrotor. © 2025 Elsevier Ltd