Unscented External Force and Torque Estimation for Quadrotors
This work addresses external force estimation for quadrotors, which is incremental as it builds on known methods for improved performance in specific applications.
The paper tackles the problem of estimating external forces and torques on quadrotors by proposing an algorithm based on the Unscented Quaternion Estimator, which outperforms existing methods in simulation and enables controllers to keep a quadrotor in a moving fan's wind field.
In this paper, we describe an algorithm, based on the well-known Unscented Quaternion Estimator, to estimate external forces and torques acting on a quadrotor. This formulation uses a non-linear model for the quadrotor dynamics, naturally incorporates process and measurement noise, requires only a few parameters to be tuned manually, and uses singularity-free unit quaternions to represent attitude. We demonstrate in simulation that the proposed algorithm can outperform existing methods. We then highlight how our approach can be used to generate force and torque profiles from experimental data, and how this information can later be used for controller design. Finally, we show how the resulting controllers enable a quadrotor to stay in the wind field of a moving fan.