Simultaneous estimation of aerodynamic and contact forces in flying robots: Applications to metric wind estimation and collision detection

In this paper, we extend our previous external wrench estimation scheme for flying robots with an aerodynamic model such that we are able to simultaneously estimate aerodynamic and contact forces online. This information can be used to identify the metric wind velocity vector via model inversion. Noticeably, we are still able to accurately sense collision forces at the same time. Discrimination between the two is achieved by identifying the natural contact frequency characteristics for both “interaction cases”. This information is then used to design suitable filters that are able to separate the aerodynamic from the collision forces for subsequent use. Now, the flying system is able to correctly respond to typical contact forces and does not accidentally “hallucinate” contacts due to a misinterpretation of wind disturbances. Overall, this paper generalizes our previous results towards significantly more complex environments.