Design and evaluation of a skin-like sensor with high stretchability for contact pressure measurement

Abstract

This paper presents the development of a new type of skin-like tactile pressure sensor array. The sensor array is scalable, flexible and stretchable and can measure pressure up to 250kPa within 30% stretching rate without damaging its mechanical structure. It can also conform to irregular three-dimensional surfaces. The sensor array consists of three layers. The top and bottom layers are formed by the array of parallel conductive strips made of silver nanowires (AgNWs) embedded in polydimethylsiloxane (PDMS) thin films. The AgNWs/PDMS conductor strips are used as stretchable interconnections to transmit electrical signals. The middle layer is made of PDMS. This film is pre-molded with holes filling with cylinder-shaped conductive elastomer for pressure measurement. In this paper, the characteristic of the AgNWs/PDMS conductor strips as stretchable interconnections is studied. The piezoresistive properties of the sensels (one sensing element is called a sensel) were measured and discussed. The performance of the tactile sensor array under stretching was also tested. With the associated scanning power-supply circuit and data acquisition system, it is demonstrated that the system can successfully capture the tactile images induced by objects of different shapes. Such sensor system could be applied on curved or non-planar surfaces in robots or medical devices for force detection and feedback.