Flexible Tactile Sensor for Tissue Elasticity Measurements

This paper presents a novel tactile sensing technique for tissue elasticity measurements. A prototype flexible tactile sensor has been successfully fabricated using polydimethylsiloxane as the structural material. The proposed sensor comprises an array of capacitors with no active elements used. By varying the sizes of sensing membranes within the capacitors, different stiffnesses of sensing diaphragms can be achieved. The elasticity of the targeted object can be thereafter measured based on the relative deflections of the sensing diaphragms. The fabricated sensor has been calibrated by an off-the-shelf polymer durometer hardness selector pack. The results show a sensing resolution of 0.1 MPa for elasticity measurement and a force sensing resolution as small as 5 mN. This flexible tactile sensor can be embedded on the distal portions of various endoscopic instruments for in vivo tissue elasticity measurements.