Contact-Informed Online Trajectory Replanning for Obstacle Avoidance in Unmanned Aerial Manipulators

Autonomous exploration in unknown areas is a challenge for unmanned aerial vehicles when traditional ranging sensors such as LIDARs or cameras fail due to dust, fog, or lack of illumination. In these situations, contact-informed navigation is leveraged by utilizing the end-effector of an unmanned aerial manipulator (UAM) to detect and exploit obstacle contacts. This work presents a contact-informed online replanning algorithm that updates an obstacle-bounding region using online wrench estimates, enabling a UAM to navigate around an unknown convex polyhedral obstacle. The planner generates joint-space setpoints that guide the tool center point (TCP) to track a reference trajectory while ensuring the multirotor body avoids the obstacle-bounding region. Two simulation cases show that this approach prevents multirotor body collisions and ensures TCP trajectory tracking.