Hoverability-Based Control Design for Reconfigurable Multi-Link Quadrotor

This paper presents a Reconfigurable Multi-link Quadrotor (RMQ) capable of adapting its morphology through variable joint angles between its arms. While such flexibility enhances adaptability, existing designs often increase system complexity, making stable hovering during reconfiguration particularly challenging. In this work, a comprehensive nonlinear dynamic model is developed to capture time varying inertial properties and configuration dependent control allocation. Based on this model, a rigorous hoverability analysis is conducted to characterize the conditions required to maintain stable hovering throughout reconfiguration. Leveraging this analysis, a real-time singularity avoidance strategy is proposed through joint motion planning based on Dijkstra’s algorithm, ensuring feasible configurations with a prescribed safety margin. To address the resulting coupled dynamics, a control framework based on a proportional integral derivative (PID) controller optimized using the Whale Optimization Algorithm (WOA) is developed to ensure consistent trajectory tracking across varying configurations. The effectiveness of the proposed approach is validated through nonlinear simulations and experimental tests, demonstrating stable hovering and accurate tracking despite significant structural variations.