Active Disturbance Rejection Control Approach to Tight Formation Flight of Unmanned Aerial Vehicles

This paper addresses the synchronized control problem of relative position and attitude for unmanned aerial vehicles(UAVs) to achieve the task of formation keeping and transformation. First, using second-order autopilot model and aerodynamic coupling model, a three-dimensional(3-D) nonlinear kinematic and dynamic model of tight formation is established. Second, based on the leader-follower structure, a double-layer active disturbance rejection control scheme of tight formation is proposed, of which the superstructure is to control the whole formation guiding, while the substructure is to adjust the geometry of tight formation. A detailed design of active disturbance rejection controllers applicable to velocity, heading and altitude three channels is included. Finally, simulation results are presented to illustrate the validity and effectiveness of the proposed controllers, which have the following properties: (1) effectively accounting for formation keeping and transformation with smaller overshoot and quicker response can be obtained. (2) good adaptive ability is verified through the comparison with PID flight controller.