Optoelectronic joint angular sensor for robotic fingers

The present paper reports the results of the development of a novel joint angular sensor conceived for integration in tendon-driven robotic hands and in data gloves used in virtual reality systems. The sensor is based on a couple LED/photodiode, mounted to two contiguous phalanges of a University of Bologna (UB) hand finger. When the joint between the considered phalanges flexes, the photocurrent measured by the photodetector changes with the angular displacement. An experimental model of the sensor is set up in order to select the optimal positioning of the components over the phalanges and an optical motion capture system is used to calibrate the sensor. The complete characterization of the sensor in terms of repeatability, linearity and noise presented in the paper together with its low cost confirm that the sensor can be effectively exploited both in feedback control loops for robotic systems as well as in data acquisition systems for virtual reality applications.