On the trustability of the safety measures of collaborative robots: 2D Collision-force-map of a sensitive manipulator for safe HRC

Abstract

Sensitive manipulators have become wide-spread in collaborative robot applications and the industry is aiming for ways to use the advantages of Human-Robot-Collaboration (HRC) in an efficient way. Nevertheless most applications do not go beyond the coexistence of humans and robots. To facilitate a closer collaboration between humans and robots we examine the ability of sensitive robots to safeguard contact situations with humans. More precisely, we study the relation between certain robot parameters and the resulting biomechanical load to humans during a potential collision. As use case we consider a generic abstraction of a pick and place application in a laboratory setup. Particularly, the effects of changing the end effector velocity and varying the pick and place position were investigated. To do so, potential contact situations within the range of the robots workspace are evaluated. A statistical model of the robot behavior is presented for the investigated application scenario, and the experimental findings are elaborated in a theoretical context. It is discussed how the deduced information can be utilized to safeguard a collaborative robot application with a flexible pick and place position and how this holistic approach leads to a safe and efficient integration of collaborative tasks in general.