Digitalized self-powered strain gauge for static and dynamic measurement

Abstract

This paper presents a digitalized self-powered triboelectric strain gauge (DSSG) for the first time. Different from conventional resistive or capacitive analogue strain responsive mechanisms, adopting the output of grated triboelectrication as sensing signal for static and dynamic strain measurement allows for digitalized strain measurement with excellent accuracy, sensitivity and linearity. Instead of analyzing voltage/current value of sliding-mode triboelectric nanogenerator (S-TENG) to evaluate strain, the DSSG exploits a grated triboelectric electrode to generate periodical output signals when the designed elastomer has relative movement with the grated electrode. A promoted real-time analysis system (RAS) enables the analysis and display of the digitalized signals. Benefiting from the micro-manufacturing techniques of grated electrode, DSSG reaches a remarkable gauge factor as high as 130 with optimized design of geometrical parameters. The results of static strain measurement prove the feasibility of using such DSSG as a self-powered transducer of tensile forces, with a minimum resolution for tensile force detection of 120 mN per cycle. At the same time, dynamic strain sensing assisted by signal processing system provides possibility of using such DSSG for real-time elbow joint motion detection and posture analysis, thereby indicating its great potentials for human-machine interface, prosthetic, and biomechanical applications.