Differential Flatness of Quadrotor Dynamics Subject to Rotor Drag for Accurate Tracking of High-Speed Trajectories

By Matthias Faessler, Antonio Franchi, Davide Scaramuzza. 2017

403 citations recorded by the source corpus.

In this letter, 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 feedforward control terms directly from a reference trajectory to be tracked. The obtained feedforward terms are then used in a cascaded, nonlinear feedback control law that enables accurate agile flight with quadrotors. Compared to the 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 feedforward control terms. The new theoretical results are thoroughly validated trough extensive comparative experiments.

Subfields: Aerospace Engineering, Control and Systems Engineering, Mechanical Engineering, Robotics & Control

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Citations in the corpus

A General Framework for Uncertainty Estimation in Deep Learning (2019, methodology): “Following previous work [36], we use the RMSE metric be-tween the reference and actual trajectory for quantitative analysis.”
Neural-Fly enables rapid learning for agile flight in strong winds (2022, background): “Another recent work focuses on deriving simplified rotor-drag models that are differentially flat (2).”
Geometrically Constrained Trajectory Optimization for Multicopters (2021, methodology): “Consequently, it is applicable to incorporate more accurate dynamics and actuator limits for any differentially flat multicopters by considering more model details such as the rotor drag (Faessler et al. 2018).”
Dynamic obstacle avoidance for quadrotors with event cameras (2020, background): “The output of this module is a velocity command, which is then fed to the position controller proposed in (54) and available as open source (http://rpg.”
The current state and future outlook of rescue robotics (2019, background): “…would be to enable a flying robot to enter structures such as earthquake‐damaged buildings through small apertures in an emergency response (right; Falanga et al., 2018) [Color figure can be viewed at wileyonlinelibrary.com] F IGURE 6 Examples of flying robot applications within the disaster…”