The digital correction of the strain gauge error

The article is aimed on the search of opportunities to improve the accuracy of remote measurements and noise immunity of measuring the stress-strain state, in particular on a detailed study of polynomial coefficients behavior for the most used range of temperatures of strain gauges. Based on the analysis of destabilizing factors, it is established that among the main destabilizing factors that limit the measurement accuracy of instrument systems equipped with strain gauges are the effects of external climatic and mechanical factors, in particular temperature, humidity and so on. The influence of the temperature range change for one of the most common materials used for the manufacture of strain gauges, namely, a constantan alloy with a minimum temperature coefficient of resistance and the variation of the temperature error values (± 10 %) on the rms error of the approximation error by power polynomials is studied. The NUMERY package has determined the dependence of the approximation error on the order of the approximating polynomial, which reveals that, over a wide temperature range, the error for the constant has a weak relationship with the polynomial order. As the calculations show, when narrowing the temperature range, the error sharply depends on the order of the approximating polynomial, and already at the sixth order it almost becomes zero. The influence of recording accuracy of tabulated values on polynomial coefficients is also investigated, and it is determined that a random error in the determination of coefficients up to ± 10 % for a constantan practically does not affect the mean square error of approximation. A method for digital temperature error correction that allows the correction of strain gauge errors by using TEDS is proposed. The efficiency of the algorithm in terms of nonlinearity of the temperature error will be determined with the accuracy of the fit of the approximating polynomial