A Robot System with Safe Contact Detection and Stopping Capabilities Based on Human Pain Tolerance.

Abstract

In this paper, we propose a human-safety-oriented design method to realize a safe robot system for human-robot coexistence. We conduct some simulations to identify problems in human-robot collision situations, and point out, based on the human pain tolerance limit which we have clarified, that a robot working next to a human should be covered with a soft material and be equipped with prompt stopping capability. First, we construct a fail-safe robot system with contact sensing and subsequent emergency stop control capabilities using a simple disturbance observer which plays an important role in checking the normal operation of a two-link DD-motor-driven manipulator. Second, we design a soft covering made of a viscoetastic material which achieves both effective impact force attenuation and high contact sensitivity, keeping impact force within the human pain tolerance limit. Finally, we demonstrate actual human-robot collision experiments to show that the contact force generated at collisions was suppressed below the human pain tolerance limit.