An optical joint position sensor for anthropomorphic robot hands

This paper presents the design of an optical position sensor integrated into a miniaturized tendon-driven robotic joint. The sensor exploits the modulation of the light power flux that goes from an infrared Light Emitting Diode (LED) to a PhotoDiode (PD) by means of a variable-thickness canal integrated into the joint itself to detect the joint position. The LED and the PD are fixed on one of the two links that compose the robotic joint, while the canal is integrated into the other link. The paper reports the basic sensor working principle, the integrated design of the miniaturized robotic joint with embedded position sensor and the experimental evaluation of the proposed device on a force/position control loop. Finally, a preliminary prototype of the UBH-IV finger in which the proposed joint with embedded position sensor are used is presented.