A Novel Hierarchical Distributed Robust Formation Control Strategy for Multiple Quadrotor Aircrafts

Multiple quadrotor aircraft system has significant advantages for performing complex tasks in dangerous environments, but it is still challenging for formation with external disturbance or internal model uncertainty. This article establishes a hierarchical distributed robust formation strategy for multiple quadrotor aircrafts, in which trajectory tracking and attitude formation are, respectively, controlled in different layers. An upper trajectory tracking controller is proposed to generate desired position for lower anti-disturbance attitude formation controller, where a bi-level adaptive terminal sliding mode controller with disturbance observers are, respectively, designed. In lower control layer, the desired velocity is generated by velocity control part to ensure quadrotor aircraft to track desired position while maintaining certain formation shape, whereas the acceleration control part is responsible for driving actual velocity of each quadrotor aircraft to desired velocity. Stability analysis shows that the prescribed formation can be realized if unknown disturbance is bounded and time constants in different layers are selected appropriately. Compared with existing results, the proposed strategy enables multiple complex tasks to be realized in different layers to improve formation accuracy and achieve interference suppression. The effectiveness is verified through both Gazebo simulation and actual experiment.