Abstract:Aiming at the problems of single fitting method and low accuracy of thermoelectric characteristic curve of thin film to thermocouple, this paper designs a curve fitting method of thermoelectric characteristics of thin film thermocouple based on polynomial interpolation. Firstly, the key structure of verification and calibration of thin-film thermocouple is introduced, and the verification and calibration platform of thin-film thermocouple is built. Secondly, the working principle of the film thermocouple verification and calibration platform is described, and the thermoelectric potential of the film thermocouple fixed point is measured. Finally, a thin film thermocouple curve fitting method using cubic spline interpolation is designed. The thermoelectric curves and some unverified thermoelectric potentials are obtained by using the interpolation method designed in this paper and Lagrange interpolation respectively. The residual sum of squares between measured and simulated values is calculated. The results show that the sum of residual squares of cubic spline interpolation and Lagrange interpolation are 0.00391961 and 0.00392917, respectively. The fitting accuracy of cubic spline interpolation is higher.