A fast optical proximity sensor skin that contains an analog computing circuit and can cover an entire link

Abstract

This paper proposes a novel optical proximity sensor skin that can cover entire robot links and has high responsiveness, wire-saving properties, and suitability for covering narrow surfaces. Moreover, it can extract information that can help to control robots. Although implementing these characteristics simultaneously has been problematic for sensor skins covering links, the proposed sensor skin achieves this using a newly developed analog computing circuit. This analog computing circuit only consists of several resistors and diodes and is based on the splitting ratio of photocurrents variation based on the design of the resistance values. If the output from the proximity sensing element is interpreted as a virtual force, the processed output denotes its magnitude and the location of the point of action. Even if multiple objects are detected, the outputs are associated with the resultant virtual force because photocurrents are merged. Therefore, the characteristics such as high responsiveness are maintained. This work fabricated a prototype to evaluate the proposed sensor skin. Then, collision avoidance experiments against human hands were conducted to validate the efficiency of the proposed sensor skin for generating robot motions. These results verified that the proposed sensor skin is suitable for robots reacting quickly to unknown environments.