@article {2018c-FaeFraSca, title = {Differential Flatness of Quadrotor Dynamics Subject to Rotor Drag for Accurate Tracking of High-Speed Trajectories}, journal = {IEEE Robotics and Automation Letters}, volume = {3}, year = {2018}, note = {Also selected for presentation at the 2018 IEEE Int. Conf. on Robotics and Automation, Brisbane , Australia}, month = {04/2018}, pages = {620-626}, abstract = {In this paper, we prove that the dynamical model of a quadrotor subject to linear rotor drag effects is differentially flat in its position and heading. We use this property to compute feed-forward control terms directly from a reference trajectory to be tracked. The obtained feed-forward terms are then used in a cascaded, nonlinear feedback control law that enables accurate agile flight with quadrotors. Compared to state-of-the-art control methods, which treat the rotor drag as an unknown disturbance, our method reduces the trajectory tracking error significantly. Finally, we present a method based on a gradient-free optimization to identify the rotor drag coefficients, which are required to compute the feed-forward control terms. The new theoretical results are thoroughly validated trough extensive comparative experiments.}, doi = {10.1109/LRA.2017.2776353}, attachments = {https://homepages.laas.fr/afranchi/robotics/sites/default/files/2018c-FaeFraSca-preprint.pdf , https://homepages.laas.fr/afranchi/robotics/sites/default/files/2018c-FaeFraSca.mp4}, author = {Matthias Faessler and Antonio Franchi and Davide Scaramuzza} }