Extensions to Dynamically-Consistent Collision Reaction Control for Collaborative Robots

Since modern robots are supposed to work closely together with humans, physical human-robot interaction is gaining importance. One crucial aspect for safe collaboration is a robust collision reaction strategy that is triggered after an unintentional physical contact. In this work, we propose a dynamically-consistent collision reaction controller, where the reactive motion is performed in one particular desired direction in Cartesian space, without disturbing the remaining ones. This results in more intuitive and more predictable behavior of the end-effector. In addition, the proposed reaction control law is independent of contact and internal observer dynamics used for collision detection. The theoretical claims are validated in simulation and experiments. The proposed reaction controller is experimentally compared with a conventional approach for collision reaction. All experiments have been conducted on a torque controlled KUKA LWR IV + lightweight robot.

Authors

• Marie Harder
• Maged Iskandar
• Jinoh Lee
• Alexander Dietrich

Keywords

• Torque
• Uncertainty
• Dynamics
• Collaboration
• Observers
• Robustness
• End effectors
• Reactive Collisions
• Optimal Control
• Directions In Space
• Human-robot Interaction
• Cartesian Space
• Collision Detection
• Theoretical Claims
• Degrees Of Freedom
• Solid Line
• Dashed Line
• Lagrange Multiplier
• Impact Force
• Null Space
• Human Operator
• Acceleration Signal
• Peak Acceleration
• Task Space
• End-effector Position
• Acceleration In Direction
• Small Drift
• Motion Path