基于回波信号相似度的气体超声流量计动态阈值法研究

doi:10.3969/j.issn.1000-1158.2022.04.08

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摘要基于双阈值法的气体超声流量计采用第1阈值检测和过零检测确定回波的到达时刻点,然而由于回波波形易受工况环境因素的影响,会导致第1阈值错误,使回波到达时刻点发生错误偏移,影响测量精度,因此提出了一种基于回波信号相似度的动态阈值法。该方法获取回波信号极大值幅值后,计算设定工况和实际工况下回波信号上升区域部分的欧式距离以评估相似度,进而根据最大相似度确定阈值电压,实现阈值的动态调整,以确保回波信号到达时刻点的准确定位,实现飞行时间的准确测量。实验结果表明,该方法在不同工况环境下具有良好的适应性,样机的测量误差优于1%,重复性优于0.2%。

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	马也驰
	赵伟国
	章圣意

关键词 ：计量学, 气体超声流量计, 动态阈值法, 回波相似度, 第1阈值检测

Abstract：The first threshold detection and zero crossing detection are often used to determine arrival point of echo signal in the gas ultrasonic flow meter based on double threshold method.However,the echo wave is easily distorted caused by environment change,which lead to the first threshold wrong setting.As a result,the arrival point of echo will be shifted to the wrong position and the measurement accuracy will be affected.Therefore,a dynamic threshold method based on echo similarity is proposed.The several maximum amplitude of echo signal are obtained,the Euclidean distance of the rising area of the echo signal are calculated to evaluate the similarity.Then the threshold voltage is determined according to the maximum similarity to realize the dynamic threshold value.The correct threshold setting ensures that the accurate positioning of echo signal arrival time point.So the accurate measurement of flight time is obtained.Finally,the experimental results show that the method has good applicability under different working conditions.The measurement error of the prototype is better than 1% and the repeatability is better than 0.2%.

Key words： metrology ultrasonic gas flow meter dynamic threshold method similarity of echo wave first threshold detection

收稿日期: 2020-08-10 发布日期: 2022-04-08

PACS:

TB937

基金资助:国家市场监督管理总局科技计划项目(2019MK146)

通讯作者: 赵伟国(1973-), 男, 陕西蓝田人, 中国计量大学副教授, 硕士生导师, 主要从事流量检测技术和智能仪表方面的研究。Email:zjufriendly@cjlu.edu.cn E-mail: zjufriendly@cjlu.edu.cn

作者简介: 马也驰(1996-), 男, 浙江衢州人, 中国计量大学在读硕士研究生, 主要研究方向为流量计量测试和智能化仪表。Email:952114676@qq.com

引用本文:

马也驰,赵伟国,章圣意. 基于回波信号相似度的气体超声流量计动态阈值法研究[J]. 计量学报, 2022, 43(4): 482-488.
MA Ye-chi,ZHAO Wei-guo,ZHANG Sheng-yi. Study on Dynamic Threshold Method Based on Echo Similarity for Ultrasonic Gas Flow Meter. Acta Metrologica Sinica, 2022, 43(4): 482-488.

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