基于最小二乘法的热电偶电势非线性拟合

Research on Thermocouple Potential Nonlinear Fitting Based on the Least Square Method

为把控铸造的温度和简化测温过程,用简单的多项式代替以前繁琐的热电偶先测电势后查表的过程,但由于分度表的非线性,需要对其进行线性拟合。在最小二乘法的基础上结合MATLAB及Visual Basic两个软件将热电偶的分度表拟合为3段3次多项式,并生成可执行程序,输入电势值即可得到对应的温度,减少工人工作量的同时对提高工业自动化有所帮助。

In order to control the casting temperature and to simplify the temperature measurement process,a simple polynomial is used instead of the previous fussy thermocouple power measurement process.However,due to the nonlinearity of the indexing table,it is necessary to carry out the linear fitting.In this article,combining the MATLAB and the Visual Basic software,the thermocouple scale is fitted to 3 cubic polynomials on the basis of the least square method.Finally,an executable program is generated and the corresponding temperature is obtained when the electrodynamic potential value is input.The fitting method could reduce the workload of workers and improve the industrial automation.