Aerial Manipulator Pushing a Movable Structure Using a DOB-Based Robust Controller

This letter deals with the problem of an aerial manipulator pushing a movable structure. Contrary to physical interaction with a static structure, suitable consideration of the interacting force during the motion of the structure is required to stably perform this movable structure interaction. To accomplish the task of pushing a structure while ensuring the stability of the aerial manipulator, we present a nonlinear disturbance-observer (DOB)-based robust control approach by regarding the interaction force as a disturbance to the system. Furthermore, to utilize the proposed controller for pushing a movable structure, we propose an algorithm to generate an end-effector position reference that enables safe operation in a realistic situation. We validate the proposed control framework with successful demonstrations on pushing two types of movable structures, a heavy rolling cart (42 [kg]), and a real-like hinged door.