Development of a Piezoresistive Force Transmitter for Gauging Yarn´s Linear Density in High-Speed Textile Machinery

A piezoresistive force transmitter has been developed for gauging the variation of yarn´s linear density with the measuring range of 0-5 N and the corresponding voltage output of 0- -5 V. The transmitter simply consists of a force sensor head and a signal processing circuit unit. The sensor head consists of a sensitive silicon chip and an elastic metal element. The chip is based on piezoresistive effect of silicon and is made using microfabrication techniques. The elastic metal element is designed using finite-element method (FEM) and fabricated by electrical discharge machining (EDM). The location of the expected maximum stress of the elastic metal element is also analyzed using FEM. The sensitive silicon chip is packaged on the elastic metal by glass powder sintering process. The signal processing circuit unit is used to amplify the sensor´s output to the standard voltage. According to the dynamic and static experiments, the experimental results show that the accuracy of the piezoresistive force transmitter is 0.203%FS and the response frequency is 878.5 Hz, so the transmitter is suitable for the auto leveling system for high-speed textile machinery.