Collision Tests in Human-Robot Collaboration: Experiments on the Influence of Additional Impact Parameters on Safety

Abstract

Human-robot collaborations are among the most promising but challenging applications for human-centered production, as both agents involved share a mutual workspace without physical barriers. Safety aspects require limiting the power and force of operations to comply with biomechanical limits in case of a collision according to the International Organization for Standardization (ISO) technical specification ISO/TS 15066:2016. This analysis requires highly elaborate physical crash tests of potential impact scenarios. Formal verification will save considerable amounts of time and effort. However, the equations presented in current guidelines need to be more accurate as many factors influencing the impact force and pressure are not considered, making these equations impractical for the evaluation of real applications. To answer the question of which parameters influence a human-robot collision, we have experimentally analyzed different collision scenarios in various configurations. The main results show the correlation of impactor geometries, edges versus rounding, and Shore hardness of the affected body region that simulates human tissue. This work presents the parameters that a formal human-robot collision verification model should contain, based on experimental tests. Furthermore, a model that identifies a collision's worst-case impacted body region is introduced. The results of this work will help in simplifying and accelerating the safety evaluation process of collaborative human-robot applications to better realize their potential.INDEX TERMS Industrial robot safety, human-robot collaboration (HRC), formal methods in robotics and automation, power and force limitation, robot collision evaluation.

Considerations on the Dynamics of Biofidelic Sensors in the Assessment of Human–Robot Impacts

“…Fischer et al [25] delved into the topic of collaboration between humans and robots in a workspace that lacks physical barriers, with a particular focus on safety. The authors argued for the need for more precise equations to evaluate impact force and pressure during collisions, as current guidelines may not be practical.…”

Actuators for Improving Robotic Arm Safety While Maintaining Performance: A Comparison Study

“…Alternatively, in [14], a finite element simulation of a Comau SMART NS 16 industrial robot and an ES-2 crash test dummy was developed and used to simulate collisions with a seated human's head, chest, and pelvis. Experimental collision results for an industrial robot colliding with a mechanical apparatus simulating part(s) of a human have been reported in [13,15,16]. Testing procedures and results for numerous head and chest collision scenarios between Kuka LWRIII, KR6, and KR500 robots and a Hybrid III crash test dummy were reported in [15].…”

“…In [13], a PUMA 560 robot collided with an apparatus employing a mass and spring to simulate the human head and neck. A Universal Robots UR3e robot, Franka Emika FE robot, and ABB GoFa robot were tested for collisions with a force measurement device consisting of a mass-spring-damper in [16]. The stiffness of the spring was changed to mimic the stiffnesses of different regions of the human body.…”