A Centralised Control Approach to Compliant Aerial Manipulation on Overhangs

Abstract Aerial physical interaction opens the door for many operations at height to be automated using flying robots. This research presents a novel manipulator design mounted on a traditional quadrotor, which employs both mechanical and software compliance to perform physical interaction on vertical walls and overhanging surfaces, such as those found under bridges. A centralised control scheme paired with an impedance filter enables direct control of the end-effector pose in the task space, without the need for separate control modes for the free-flight and contact phases. A spring-loaded prismatic joint on the manipulator provides mechanical compliance, while doubling as a force-feedback for the impedance filter by measuring the spring displacement. Flight experiments validate our approach for exerting high forces at height with varying wall inclinations, with a total of 43 successful experiments carried out in four different settings. In these flight experiments an average maximum force of 5.66 N, or 19.3% of the system's weight was sustained.