Perching of quadrotor using adaptive second-order continuous control in the presence of uncertainties

The perching maneuver enables a quadrotor to make stable contact with vertical surfaces for prolonged monitoring, which significantly enhances mission endurance and energy efficiency in inspection and surveillance tasks. To achieve a stable perching maneuver, this study proposes an adaptive second-order continuous control (ASOCC) in contact-based inspection applications. A novel finite-time convergent disturbance observer compensates model uncertainties and external disturbances, including aerodynamic and wall effects. The closed-loop Lyapunov stability of the proposed observer-controller system is also established. The effectiveness of the ASOCC strategy is validated through extensive simulation studies under various conditions, including step response, model uncertainties, and external disturbances. Comparative evaluations against existing control strategies reveal that the proposed method offers higher precision, stronger robustness, and better resistance to external disturbances when assessed through standard tracking error-based performance indices. Additionally, experimental trials verify that the quadrotor consistently performs a stable perching maneuver on vertical walls under both indoor and outdoor conditions.