Collision detection for safe human-robot cooperation of a redundant manipulator

Human-robot cooperation have a potential risk of collision between a human and a robot, and collision detection is one of the most practical solutions to ensure human safety during this cooperation. However, collisions during human-robot cooperation cannot be reliably detected using conventional collision detection methods because collision forces and intended interaction forces cannot be distinguished from each other. In this study, we propose a collision detection method that can be used to distinguish collisions from intended task force at the end-effector. To this end, we developed a collision detection index that is decoupled from the intended external force applied for human-robot cooperation. The proposed method was verified through several experiments, and experimental results show that collisions can be detected regardless of the presence of physical contact between humans and robots for cooperation.