Distributed super twisting controller for multiple quadrotors

The distributed cooperative tracking control problem for a group of quadrotors in a three-dimensional space is addressed in this paper. The controller design is divided in two stages. In the first stage, local distributed controllers for the translational dynamics are designed, forcing the quadrotor to asymptotically track the desired trajectory with the required separation and therefore a specific formation. In the second stage, the rotational dynamics is asymptotically stabilized. The controllers implemented in both stages are based in a combination of block control technique and the super twisting control algorithm which ensures robustness with respect to external disturbances and parameter uncertainties. Moreover, a first order exact differentiator is used to estimate the virtual control inputs, simplifying the control law design. The stability proof of the complete closed-loop system is shown to be asymptotically stable. Finally, numerical simulations are carried out to show that theoretical conclusions are effective.