Geometric Formation Tracking of Quadrotor UAVs Using Pose-Only Measurements

In this brief, the problem of formation control of a swarm of quadrotor UAVs with a group leader using only position and attitude measurements is addressed. A distributed formation controller is proposed for the quadrotor team, which consists of an outer-loop position controller to achieve the desired formation without linear velocity measurements, and an inner-loop attitude controller to regulate the attitudes without angular velocity measurements. Two auxiliary dynamic systems driven by proper inputs respectively are designed to overcome the lack of linear and angular velocities. The position controller derived from the intermediary translational control inputs guarantees the boundedness of the actual thrust force inputs. The attitude controller is developed directly using rotation matrices to avoid the singularities of Euler-angles and the ambiguity of quaternions. The stability analysis is presented using Lyapunov stability theory on cascade systems, and the effectiveness of the proposed control strategy is demonstrated through numerical simulations.