Abstract
Reasonable risk estimation is indispensable for building a safe human-robot coexistence system. Risks are estimated from the severity of harm and the probability of occurrence of harm in which we focus on the latter. Taking into consideration the possibility of avoiding or limiting harm, we propose a new method for estimating the collision probability between an end-effector tip and an eyeball when the robot goes out of control. With a self-diagnosis function, the robot makes the braking motion and comes to a complete stop. The method basically computes the intersection between the two volumes of the manipulability ellipsoid constructed through motions of the end-effector tip and a human eye.
