Optimization of Sensitivity Induced by Substrate Strain Rate for Surface Acoustic Wave Yarn Tension Sensor

In this paper, we propose a novel sensitivity optimization design scheme for the yarn tension sensor using surface acoustic wave (SAW) device by improving the strain rate of the SAW yarn tension sensor substrate. The yarn tension sensor, operating at 169.4 MHz, is designed as an oscillator fabricated on a 42°Y-X quartz substrate. Based on regression analysis and finite-element analysis, two mathematical models are established and a linear programming model is built to obtain the best sensitivity. Moreover, the determination coefficients of the two mathematical models both are >0.99, which means that the regression models fit the experimental data exactly. The linear programming results show that the maximum sensitivity will be achieved when the SAW yarn tension sensor substrate length is 19 mm and its width is 3 mm within a fixed interval of the substrate size. The SAW yarn tension sensor with the size of 19 mm × 3 mm was fabricated. Experimental results show that the actual optimal sensitivity 3.13 kHz/g was obtained, confirming that the sensitivity optimization design scheme is effective and applicable.