基于蒙特卡罗方法的虚拟仪器测量不确定度评估

提出一种数字化虚拟仪器测量结果不确定度的评估方法,其基本思路是利用概率事件仿真技术(Monte Carlo方法)产生服从特定概率分布的随机数来模拟虚拟仪器测量链中的随机误差源,模拟随机误差与采样数据一同进入虚拟仪器信号处理模块,获得一系列伪测量结果,再用伪测量结果的统计标准方差表征虚拟仪器测量结果的不确定度,并运用虚拟仪器设计平台提供的扩展机制,建立了PCI-6024数据采集卡的随机采样误差仿真模块.应用该模块实现对信号有效值测量结果不确定度的评估,并将评估结果与理论值相比较,获得了较好的一致性.

Measurement Uncertainty Digital Evaluation for Virtual Instrument Based on Monte Carlo Method

A numerical evaluation method is proposed to solve uncertainty evaluation problem of virtual instrument measurement system. According to probability event simulation technique (Monte Carlo method), the random distributed variables are generated to simulate random error source in virtual instrument measurement chain. The sampling data and corresponding simulation random error data are entered together into the virtual instrument signal processing module, and a series of pseudo measurement results are obtained. The statistical standard deviation of the pseudo measurement results is used to indicate the ultimate measurement uncertainty of the virtual instrument. By means of the expandable mechanism provided by the virtual instrument design frame, the author established a random sampling error simulation module for PCI-6024 DAQ board. Using this module we carried out the uncertainty evaluation for the signal RMS measurement results. The numerical simulation results are compared with the results from theoretical analysis method, which demonstrates the validity of the proposed digital uncertainty evaluation method.