Collision-Free Formation Control for Multiple Quadrotor-Manipulator Systems

In this paper, we develop a formation control law with collision avoidance for multiple quadrotor-manipulator systems that each quadrotor is equipped with a robotic manipulator. Firstly the kinematic and dynamic models of a quadrotor with multi-DOF robotic manipulator are built together using Euler-Lagrange (EL) equations. Based on the aggregated dynamic model, we propose a control scheme consisting of position controller, attitude controller and manipulator controller, respectively. The desired formation is achieved by the proposed position controller and attitude controller, while the collision avoidance is guaranteed by an artificial potential function (APF) method. The robotic manipulators are able to perform cooperative missions by the proposed manipulator controller. The overall stability of the closed-loop system is proven by a Lyapunov method and Matrosov's theorem. In the end, the proposed control scheme is demonstrated by a formation flying mission of four quadrotors with 2-DOF manipulators.