Collision-Free Distributed Control for Multiple Quadrotors in Cluttered Environments With Static and Dynamic Obstacles

To ensure robust flight of multiple quadrotors in unknown environments, this paper proposes a distributed cooperative control algorithm with a separation-merge mechanism to solve the problem of safe flight and formation reconfiguration. The separation-merge framework integrates the obstacle avoidance mechanism, inter-robot collision avoidance mechanism, and formation reconfiguration mechanism, and couples them all to the control layer. Obstacle detection mechanism and velocity adjustment mechanism are designed based on the obstacle avoidance behavior of the pigeons. And a rotational potential energy is introduced to solve the case of local minima and oscillations where the rotation angle can be changed in real-time according to the relative position. Inspired by spring damping system, a collision avoidance mechanism is designed with the help of Hooke's law with damping. A formation reconfiguration mechanism is designed based on consensus theory, which enables multiple quadrotors to quickly return to the prescribed formation after obstacle avoidance. The proposed method is integrated into a multi-quadrotor system and its effectiveness is verified in the visualization simulator and outdoor experiments.