Development and characterisation of elastomeric tape sensor fabrics for elbow angle measurement

Abstract

This paper deals with the development of electro-active elastomeric fabric sensor using silver coated polyamide yarn at the centre of the tape along with polyester and rubber yarns and its electrical characterisation for the application towards elbow angle measurement. Box and Behnken 3-variable and 3-level experimental design has been used and 15 different samples are produced. The resistance change in the samples caused by linear extension as well as the angular movement of the elbow is measured. <span style="mso-bidi-font-weight:bold">The variables for sensor design have been optimized using gauge factor (∆<i>r</i>/∆<i>x</i>) values as dependent variable and the results show that the variables such as number of conductive threads, picks per inch and rubber: polyester thread ratio influence the ∆<i>r</i>/∆<i>x</i> value negatively. Different sensor characteristics have also been analysed. The sample with 4 conductive threads, 20 picks/inch and 1:8 polyester : rubber ratio shows a higher gauge factor of 0.583 and has proportional resistance change with length; this sample is therefore chosen to be good among all the 15 samples developed. It is also observed that this sample with higher sensitivity value can be used to measure elbow joint up to 90⁰ angle.

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