A deformable and deformation sensitive tactile distribution sensor

For robots to possess high dexterity and interact intelligently with objects, a deformable tactile sensor skin which can also sense the deformation is of great importance. However conventional tactile sensors are not suitable for this purpose mostly due to the embedded wiring inside the sensing area. To overcome this problem, we have implemented EIT (electrical impedance tomography), a technique based on inverse problem theory, which can estimate the resistivity distribution within an electrical conductor by using only measurements from its boundary. By applying EIT to conductive materials such as pressure sensitive conductive rubbers, a deformable and deformation sensitive tactile distribution sensor can be realized. In this paper, some of the basic characteristics of the EIT based tactile sensor are reported. Also, we have demostrated how the conductive rubber sheets can be used with EIT to form a stretch distribution tactile sensor which detects sophisticated stimulations such as rubbing and pinching. In the end, we introduce our original conductive knit with high stretchability and low hysteresis, which can easily be implemented over complex 3D surfaces such as the face and also highly stretching areas such as the elbow joint.

I. Introduction

One of the main differences between living organisms and conventional robots is the morphological form of the body surface. Living organisms have soft and deformable skin and at the same time are able to sense multiple tactile stimulations such as light touch, pressure, stretch and heat on their bodies.