Comparative Performance Study of Strain Gauge Sensors for Ion Thrust Measurement

A strain gauge based thrust measurement system has been developed, by fabricating a thrust balance with four columns. In order to compare the performance of the different types of strain gauges for ion thrust measurement, foil type strain gauges were bonded to the first column and semiconductor strain gauges were bonded to the second column. Whereas, thin film strain gauges of NiCr and Pt-W materials were deposited on to the third and fourth columns respectively. The strain gauges of a particular type in each column, connected in Wheatstone bridge configuration, were calibrated to measure the thrust produced using Lami's principle and the performance was studied. Strain gauge bridge sensitivities varied from about 6μV/mN to 115μV/mN and the non-linearity varied from about 0.98 % to 2.84 % for bridges formed by the different types of strain gauges. Details on the calibration and simultaneous comparative performance study of the system developed have been presented