Dynamic surface-based distributed practical predefined-time cooperative control for flight formation of a novel small tandem-rotor wheeled UAV.

A novel practical predefined-time sliding mode control strategy is proposed for the flight formation of a small tandem-rotor wheeled UAV (TRW-UAV) with unknown upper bound external disturbances and uncertainties in this paper. Firstly, a new predefined-time sliding mode surface is proposed to guide all errors of the position and velocity loops to converge to the origin in a predefined-time. Furthermore, a dynamic surface control approach is utilized to circumvent the higher-order differentiation when controlling the actuator loop. Secondly, a predefined-time adaptive law is designed for estimating external disturbances and uncertainties during the controller design process to construct a distributed practical predefined-time formation cooperative control strategy. Thirdly, a novel practical predefined-time criterion is utilized to rigorously demonstrate the stability of the proposed control strategy. Finally, the simulation results indicate that the proposed control strategy can deliver the practical predefined-time control when there are external disturbances and model uncertainties, and with higher convergence accuracies compared to some of the existing methods.