Adaptive Robust Tracking Control for Underactuated Quadrotor Unmanned Aerial Vehicle with Prescribed Performance

Quadrotor unmanned aerial vehicle (Q-UAV) is an underactuated system, which is often used in complex environments, such as maintenance tasks in pipelines. However, flying in pipelines will lead to strong ground effect, implying that the Q-UAV will face time-varying uncertainties. Since the flight space is limited, it needs to achieve agile and high-security flight to avoid collisions. This research proposes an adaptive robust tracking control method to ensure that the Q-UAV can complete the agile and high-security flight missions. Agile and high-security flight is guaranteed by achieving prescribed transient and steady-state performance (PTSSP). Our approach takes into account (potentially rapid) time-varying uncertainties with unknown bounds. We formulate the desired flight altitude and attitude trajectories as equality constraints and the PTSSP as inequality constraints, and use state transformation approach to transform the inequality constraints into equality constraints. Simulation results showcase the superior performance of the proposed control method. This study represents endeavor to accomplish agile and high-security flight of Q-UAV while considering (potentially rapid) time-varying uncertainties stemming from complex environments.