Signal processing for slip and contact sensing and its application to a two-fingered robotic hand

Abstract

Signal processing for slip and contact sensing for a robotic tactile sensor is presented. Small strips of piezoelectric film (PVDF) were embedded in the fingertip of a robotic finger made of silicon rubber. The sensor detected the vibration caused by slip and contact. A short impulsive vibration was generated when the finger made contact with an object, and a random noise-like signal was observed when slip occurred at the fingertip. Slip was differentiated from contact by counting the number of peaks in the waveform within a 6.4∼ms interval. This non-linear filtering method was shown to be more effective than ordinary frequency domain filtering. Several experiments using the two-fingered robotic hand are presented to demonstrate the importance of slip sensing in manipulative motion.