摘要
基于双阈值法的超声水表通过第一、二阈值电压检测确定回波信号的特征点和到达时间。然而由于超声水表回波特性易受测量环境影响,导致回波信号的特征点和到达时刻发生错误偏移,从而影响超声水表的测量精度。针对以上问题,提出了一种基于双阈值法的回波特征峰搜索方法。该方法先预设回波特征峰和到达时间,并通过声速随温度的变化关系自调整预设到达时间;然后利用预设到达时间与测量得到的到达时间之间的关系进行回波特征峰的搜索,以获得回波信号特征点的准确定位,从而降低温度变化对到达时间测量的影响,获得准确的飞行时间。流量测试实验结果表明,样机在温度为10℃、20℃和50℃时具有良好的计量特性。高区流量的最大计量误差小于1.00%,重复性优于0.40%;低区流量的最大计量误差小于2.00%,重复性优于0.60%。样机满足一级水表的性能要求,验证了该方法的合理性。
Characteristic point position and echo arrival time of the ultrasonic water meter based on the dual-threshold method are determined by the first and second threshold voltage detections.However,the characteristic point position and arrival moment of the echo signals are susceptible to deviation from the actual values due to changes in the measurement environment,thereby decreasing the measurement accuracy of the ultrasonic water meter.To address this issue,an echo characteristic peak search method based on the dual-threshold method is proposed.The echo characteristic peak and arrival time are preset firstly,and the echo arrival time is self-adjusted using the relationship between the speed of sound and temperature.Then the echo characteristic peak is searched by comparing the preset arrival time with the measured arrival time to accurately position the echo signal characteristic point.This reduces the effect of temperature variations on the arrival time and ensures accurate time-of-flight measurements.Flow test experiment results show that the prototype exhibits excellent metrological characteristics at the temperatures of 10℃,20℃,and 50℃.The maximum measurement errors of the prototype are less than 1.00%at high flow rates and less than 2.00%at low flow rates.Repeatability is better than 0.40%and 0.60%,respectively.The prototype meets the performance requirements for accuracy class 1 water meters,proving the method's validity.
作者
余洪祥
王成李
赵伟国
蒋延付
YU Hongxiang;WANG Chengli;ZHAO Weiguo;JIANG Yanfu(College of Metrology and Measurement Engineering,China Jiliang University,Hangzhou 310018,Zhejiang,China;Zhejiang Key Laboratory of Flow Measurement Technology,Hangzhou 310018,Zhejiang,China;Hangzhou Seck Intelligent Technology Co.,Ltd,Hangzhou 311115,Zhejiang,China)
出处
《声学技术》
北大核心
2025年第4期547-553,共7页
Technical Acoustics
关键词
超声水表
双阈值法
回波信号
回波特征峰
飞行时间
时差法
ultrasonic water meter
dual-threshold method
echo signal
echo characteristic peak
time of flight
timedifference method
作者简介
余洪祥(1998-),男,贵州盘州人,硕士研究生,研究方向为流量计量测试和智能化仪表;通信作者:王成李,E-mail:wcli12@163.com。
