Critical contact pressure and transferred energy for soft tissue injury by blunt impact in human-robot interaction

The peak mean contact pressure and the total transferred energy are discussed as the dominant parameters of bruise tolerance by blunt impact in order to obtain safety criteria for robot design in human-robot interaction. Impact tests are conducted using live pigs with the permission of the ethical committee. A 25 mm-diameter cylindrical impactor is used to represent moving parts of robots. Samples of soft tissue are stained, and capillary damages are investigated by microscopy. The results show that there is no capillary damage if the peak mean contact pressure is less than 1.3 MPa and the total transferred energy is less than 87 kJ/m
²
. The probability of injury as a function of these parameters is obtained using logistic regression of the the experiment results.