Development of fingertip tactile sensing chips for humanoid robots

This paper presents the development of tactile sensing chips, for the fingertips of humanoid robots. In the first phase of development, piezoelectric polymer-MEA (microelectrode array) based test chips have been realized. Each chip comprises of 32 microelectrodes, epoxy-adhered with a thin piezoelectric polymer (PVDF-TrFE) film. The diameter of each microelectrode or dasiataxelpsila (tactile element) is 500 mum and the center to center distance between taxels is 1 mm. The tactile sensing chips have been experimentally evaluated over a wide range (0.02 - 4N or ~ 2 gmf- 400 gmf) of dynamic normal forces and frequencies (2 Hz - 5 KHz) by applying variable force with constant frequency in the first case and constant force with variable frequency in latter. The cross-talk, among adjacent taxels on the chips, is found to be approximately 20%. Finally, the ability of the chips to identify object material on the basis of their hardness is also demonstrated.