五孔测针标定曲线数学模型的计算机控制

Computerized Mathematical Model of Demarcated Curve for Five-hole Measuring Needle

由于三维流场测试工作及计算量繁重 ,采用传感技术实现三维流场的自动测试 ,计算机选出最优拟合曲线与实测数据相比较 ,因而达到测试三维流场风流目的。利用回归分析原理 ,将感压元件五孔测针的一系列标定曲线建立了相应的数学模型 ,采用MATLAB语言 ,实现了对标定曲线的拟合 ,用PLOT函数实现了对拟合标定曲线的自动绘制。同时考虑高次多项式 (拟合次数n >10 )易出现振荡的特点 ,故在拟合次数n从 1～ 10可能拟合多项式中 ,选出最优多项式。通过数学模型的应用实现了由计算机控制 ,从而为有效利用传感技术对三维流场的自动化测试提供了可能性。

Considering the cumbersome computing and measuring of three dimensional flow field, sensor technology is adopted to realize its automatic test. Through the comparison of the optimal fit curve selected by computer and the measured data, automatic test in three dimensional flow field is realized. A mathematical model is established by minimal error square summation based on a series of demarcated curves of five hole measuring needle, a kind of pressure inducing element. The fitting of the demarcated curves is realized by MATLAB language, and the automatic plotting of the fitted demarcated curves is realized by PLOT function. Considering that high order (when n >10) moment may occur concussion, the fitting order n from 1 to 10 is chosen. Then the mathematical model is computerized, which enables to effectively use the sensor technology in automatic test in three dimensional flowing field.