Robots that work alongside humans, such as collaborative and personal care robots, are being introduced into workplaces and households. In order to prevent injuries resulting from inappropriate contact between these robots and the human body, it is essential to establish safety criteria for contact forces. This study developed an in vivo experiment method with the ultimate goal of determining safety criteria based on the contact force threshold that causes injury. To investigate the effect of contact duration on the threshold, an apparatus was used in which an indenter representing a moving part of a robot came into contact with a specimen. The contact force was kept constant for an arbitrary period of time by force control. Preliminary results from in vivo experiments confirmed that the method developed could be used to obtain data on the effect of duration on the skin injury threshold of a human finger.
Fujikawa et al. (Wed,) studied this question.