Risk-aware Motion Planning for Collision-tolerant Aerial Robots subject to Localization Uncertainty

This paper contributes a novel strategy towards risk-aware motion planning for collision-tolerant aerial robots subject to localization uncertainty. Attuned to the fact that micro aerial vehicles are often tasked to navigate within GPS-denied, possibly unknown, confined and obstacle-filled environments the proposed method exploits collision-tolerance at the robot design level to mitigate the risks of collisions especially as their likelihood increases with growing uncertainty. Accounting for the maximum kinetic energy with which an impact is considered safe, alongside the robot dynamics, the planner builds a set of admissible uncertainty-aware and collision-inclusive paths over a horizon involving multiple motion steps. The first step of the best path is executed by the robot, while the procedure is then repeated in a receding horizon manner. Evaluated in extensive simulation studies and experimental results with a collision-tolerant flying robot, the planner successfully considers the interplay between uncertainty and the likelihood of a collision, balances the risks of possible impacts and enables to navigate safely within highly cluttered environments.