Fixed-Time Control for eVTOL with Time-Varying Centroid via Fully Actuated System Approach

This paper addresses the tracking control issue of an electric vertical take-off and landing (eVTOL) with the time-varying centroid caused by load shaking during logistics transport missions. By using quaternion-based attitude representation, the eVTOL model with the time-varying centroid is obtained. To inject the fully-actuation properties, the eVTOL model is transformed into a fully-actuated model through variable eliminations and derivations. Considering the adverse effects of the system’s time-varying centroid, external disturbances, and the lack of comprehensive motion information, a fixed-time observer and a fixed-time controller are designed via a fully actuated system approach. To circumvent the need for explicit Lyapunov functions, a novel fixed-time implicit Lyapunov stability criterion is proposed for stability analysis. Finally, a numerical simulation affirms the effectiveness and superiority of the presented control strategy.