Shifting Underactuated Configuration Variables in Aerial Manipulation by Adding an Actuated Arm

Multicopter uncrewed aircraft systems (UAS) commonly use parallel rotors to create body-fixed thrust and torque for control, leaving these systems underactuated. Under-actuation poses a significant challenge in tasks where attitude is critical, such as in collision-based aerial manipulation. Planning and control of system state at collision is required to ensure safe post-collision recovery. In particular, setting up pre-impact states such that impulses do not produce moments about mass centers can ensure recoverable departure velocities. To address the underactuated nature of UAS for collision-based aerial manipulation, this paper presents a UAS with an attached actuated pogostick. While the UAS with actuated pogostick is still underactuated, closing a control loop on the collision variables critical to managing collision response becomes possible with the new system equations. The proposed approach leverages an optimal trajectory planner coupled with a run-time controller based on partial feedback linearization of the UAS with actuated pogostick. Results show that the addition of the actuated pogostick enables setup for recoverable post-collision states when given dynamically feasible trajectories from the optimal trajectory planner.