Application Of Substantial And Sustained Force To Vertical Surfaces Using A Quadrotor

One of the challenges in the interaction between aerial manipulators (drones with manipulator arms) and the environment is to maintain stability under high interaction forces. The dynamics of the system change, and due to limitations to the drone-platform-- the drone not being to apply sideways forces and having limited yaw-torque-- stability is not naturally guaranteed.

In this video we demonstrate a new control approach to overcome these limitations. The video shows a quadrotor drone with manipulator pushing on the environment. More precisely, the stability is achieved using a state-feedback approach to compensate for the roll and yaw errors. This approach uses the linearized contact dynamics under pseudo-static conditions. The key element is that non-zero roll-states are used to compensate for errors   in the yaw-state. At a certain point the drone reaches pitch angles of over 45º. Given that the drone has a mass of  1.5 kg, this means that the drone is pushing with 15N(!) of force on the environment. The video demonstrates that the drone is easily able to maintain stability over a longer time period.

These high interaction forces can be extremely useful when operating tools on the environment, as tasks such as grinding and brushing require sufficient contact pressure to function.