Approaching Asimov’s 1st Law: The ”Impact” of the Robot’s Weight Class

The desired coexistence of robotic systems and humans in the same physical domain, by sharing their workspace and actually cooperating in a physical manner, poses the very fundamental problem of ensuring safety to the user. In this paper we will show the influence of the robot mass and velocity during blunt unconstrained impacts with humans. Several robots with weights ranging from 15-2500 kg at different impact velocities are going to be impacted with a mechanical human head mockup. This is used to measure the so-called Head Injury Criterion, mostly a measure for brain injury. Apart from injuries indicated by this criterion we point out that e.g. fractures of facial bones are actually very likely to occur during collisions at typical robot velocities. Therefore, this much more appropriate injury mechanism has to be evaluated more in detail. Finally, we motivate the need to investigate possible injuries occurring if the human is clamped by determining the braking distance of the investigated robots.