压力传感器动态校准不确定度评定

压力传感器动态校准不确定度是表征其测量精度的重要指标.提出一种用于压力传感器动态校准不确定度评价的灰色方法.首先,使用正弦压力发生器产生标准的正弦压力信号驱动被校传感器,获取传感器特征输出;然后采用灰色关联分析处理传感器特征数据,得到权重数列;之后建立灰色模型并计算出各校准频率点的灰色偏度;最后采用加权最小二乘法去拟合以得到的工作频率范围内所有频率点的不确定数据,建立起被校压力传感器的动态校准不确定度模型.设置了幅值变化及不变两种情况下的实验验证方案,使用本文所提灰方法及黄方法分别对各方案下的数据进行处理;实验结果的对比表明:两种方案下所得动态校准不确定度曲线模型具有一致性;其中幅值变化情况下,两种方法在指定校准频率点所得校准不确定度的相对误差优于6%,在测试频率点相对误差也小于10%;幅值不变情况下,在大部分频率点处所得相对误差普遍小于5%,部分优于0.018%.实验分析证明,所提灰方法能很可靠地评估压力传感器动态校准不确定度. 

Uncertainty evaluation for the dynamic calibration of pressure transducer

The uncertainty of dynamic calibration for pressure transducer is a key indicator of its dynamic measurement precision. A novel grey method (GM) was proposed to evaluate the dynamic calibration uncertainty of pressure transducer. Firstly, a sine pressure generator was used to produce required sine pressure signal to drive the calibrated pressure transducer and obtain output of transducer. Secondly, using the grey relational analysis to deal with the measurement sequences outputted, a weighted value sequence was obtained. Thirdly, a grey model was established to calculate the calibration uncertainty of appointed frequency. Finally, a weighted least-square fitting method was applied to do fitting with the calibration uncertainty of appointed frequency, and then a dynamic calibration uncertainty model was established. An experimental verification under the calibration condition of changing amplitude and unchanging amplitude was set up. Grey method and Huang method (HM) were used to process the output of pressure transducer separately. The results show that the curve models of dynamic calibration uncertainty are consistent with each other in the setting condition. What is more, under changing amplitude, the relative error of calibration uncertainty obtained by the two methods is superior to 6% at appointed frequency points and is also less-than 10% at testing frequency points. Under unchanging amplitude, the relative error is less than 5% at most of frequency points and is superior to 0.018% at some testing frequency points. Based on the above analysis, it can be approved that the grey method can evaluate the dynamic calibration uncertainty of pressure transducer reliably.