Distributed Event-Triggered Collision Avoidance Formation Control for QUAVs With Disturbances Based on Virtual Tubes

To guarantee the collision avoidance of the quadrotor unmanned aerial vehicles (QUAVs) with limited network resources and external disturbances in a complex environment, a distributed event-triggered (ET) collision avoidance formation controller is proposed in this article. To improve the robustness of the QUAVs, the parameter adaptive method (PAM) is used to tackle the influence of the external disturbance. The virtual tube (VT) is designed individually for each QUAV to avoid the collision between the QUAVs. As long as the distances between the VTs are greater than the minimum safe distance for the QUAVs, and no QUAV exceeds the boundary of the corresponding VT, the collision will not occur. Furthermore, to restrict the QUAV in the corresponding VT, the fuzzy artificial potential field with coefficients adjusted by predicting the future position of the QUAV by using both the relative position and velocity, is established and distributed around the boundary of the VT. Thus, the QUAVs are restricted to the VT and the collisions are avoided. Then, the distributed ET collision avoidance formation controller is designed by the VT and the PAM. A dynamic ET mechanism is presented to release the network load, the triggered frequency being heavily related to the distance between the position of the QUAV and the boundary of the VT. Furthermore, the closed-loop system boundedness has been certified by the Lyapunov theory. Finally, comparative flight experiments are performed to verify the effectiveness and the superiority of the proposed controller.