Safety for physical human-robot interaction (pHRI) is a major concern for all application domains. While current standardization for industrial robot applications provide safety constraints that address the onset of pain in blunt impacts, these impact thresholds are difficult to use on edged or pointed impactors. The most severe injuries occur in constrained contact scenarios, where crushing is possible. Nevertheless, situations potentially resulting in constrained contact only occur in certain areas of a workspace and design or organisational approaches can be used to avoid them. What remains are risks to the human physical integrity caused by unconstrained accidental contacts, which are difficult to avoid while maintaining robot motion efficiency. Nevertheless, the probability and severity of injuries occurring with edged or pointed impacting objects in unconstrained collisions is hardly researched. In this paper, we propose an experimental setup and procedure using two pendulums modeling human hands and arms and robots to understand the injury potential of unconstrained collisions of human hands with edged objects. Based on our previous studies, we use pig feet as ex vivo surrogate samples - as these closely resemble the physiological characteristics of human hands - to create an initial injury database on the severity of injuries caused by unconstrained edged or pointed impacts. The use of such experimental setups and procedures in addition to other research on the occurrence of injuries in humans will eventually lead to a complete understanding of the biomechanical injury potential in pHRI.

翻译：物理人机交互（pHRI）的安全性是所有应用领域的主要关切。尽管当前工业机器人应用的标准化提供了解决钝性冲击疼痛起始点的安全约束，但这些冲击阈值难以应用于边缘或尖端冲击器。最严重的损伤发生在可能产生挤压的约束接触场景中。然而，仅在某些工作空间区域会出现可能导致约束接触的情况，并且可通过设计或组织方法予以避免。剩余的风险是由难以在保持机器人运动效率的同时避免的无约束意外接触所造成的人类身体完整性损害。尽管如此，关于边缘或尖端冲击物体在无约束碰撞中造成损伤的概率和严重程度的研究仍极为匮乏。本文提出了一种实验装置和流程，使用两个分别模拟人手与手臂以及机器人的摆锤系统，以探究人手与边缘物体发生无约束碰撞时的损伤潜力。基于我们先前的研究，我们采用猪蹄作为离体替代样本——因其生理特征与人手高度相似——来建立关于无约束边缘或尖端冲击所致损伤严重程度的初始损伤数据库。此类实验装置和流程的运用，结合其他关于人体损伤发生机制的研究，最终将促成对pHRI中生物力学损伤潜力的全面理解。