Distributed Tactile Sensors for Tracked Robots

A tracked wheel i.e. a crawler is one of suitable movement mechanisms to traverse extreme environments without getting stuck on obstacles. For improving their mobility, tactile sensing of the contact surface of the tracked wheel will help the motion control efficiently by detecting slips and stumbles. This research proposes a useful distributed tactile sensing system for the tracked wheel. To apply a number of tactile sensors to the tracked wheel, an electric wiring is a big problem because the wheel rotates continuously. The optical tactile sensing system proposed can estimate contact conditions of the surface in a non-contact way. When the tracked wheel gets deformed by friction, crawler shoes on the contact area incline against the tangential force. Our system can detect the inclination of the shoes by the pairs of a LED and a phototransistor attached on the inside chassis. We developed a special optical reflector, which responses only to its inclination not to its vertical movements, using a retroreflector and a microlouver film. The reflector showed enough performances for the proposed sensing system.