Development of Fingertip Tactile Sensor for Detecting Normal Force and Slip

Abstract

In this paper, we present the flnger tip tactile sensor which can detect contact normal force as well as slip. The developed sensor is made of two difierent materials, such as polyvinylidene ∞uoride(PVDF) that is known as piezoelectric polymer and pressure variable resistor ink. In order to detect slip to surface of object, a PVDF strip is arranged along the normal direction in the robot flnger tip and the thumb tip. The surface electrode of the PVDF strip is fabricated using silk- screening technique with silver paste. Also a thin ∞exible force sensor is fabricated in the form of a matrix using pressure variableresistorinkinordertosensethestaticforce. Thedevelopedtactilesensorisphysically∞exibleanditcanbedeformed three-dimensionally to any shape so that it can be placed on anywhere on the curved surface. In addition, we developed a tactile sensing system by miniaturizing the charge amplifler, in order to amplify the small signal from the sensor, and the fast signal processing unit. Thesensorsystem is evaluated experimentally andits efiectiveness isvalidated.