Automatic tracking method of reference waveform of mine ultrasonic gas flowmeter
-
摘要: 为了提高矿用超声波气体流量计的准确性，针对互相关检测信号存在“跳波”现象并影响超声波渡越时间测量精度的问题，提出了一种矿用超声波气体流量计参考波形自动跟踪方法。在计算超声波渡越时间的同时，对超声波参考波形和实时接收信号波形进行互相关运算，并计算互相关检测的可信度，设定可信度有效阈值和参考波形更新阈值，对互相关系数进行可信度评审，判定参考波形是否更新。可信度小于有效阈值时，判定接收信号无效，重新发送超声波信号；可信度大于更新阈值时，判定接收信号波形与参考波形高度吻合，不需要更新参考波形；可信度介于有效阈值与更新阈值之间时，判定接收信号有效，用当前接收信号波形替换原参考波形，实现参考波形自动跟踪。分析了可能造成超声波渡越时间差错1个波形周期的2种超声波接收信号波形变化：包络连续形变和包络瞬间畸变。气体流速、温度、压力的变化会导致接收信号包络发生连续性变化；尖峰脉冲、随机信号和周期干扰等可能导致超声波接收信号包络发生瞬间畸变，包络瞬间畸变可分为主峰严重畸变、主峰微小畸变、非主峰畸变3种情况。试验结果表明，在不同流速、温度、压力、噪声影响下，超声波气体流量计的相对误差不超过±1.0%，满足精度1.0级测量要求，参考波形自动跟踪方法为流量测量的准确性和可靠性提供了保障。Abstract: The accuracy of mine ultrasonic gas flowmeter needs to be improved. The cross-correlation detection signal has 'signal hopping' phenomenon and affects the measurement precision of ultrasonic transit time. In order to solve the above problems, this paper proposes an automatic tracking method of reference waveform of mine ultrasonic gas flowmeter. While calculating the ultrasonic transit time, the cross-correlation operation is carried out between the ultrasonic reference waveform and the real-time received signal waveform. The reliability of the cross-correlation detection is calculated. The reliability effective threshold value and the reference waveform update threshold value are set. The reliability of the cross-correlation coefficient is evaluated so as to determine whether the reference waveform is updated. When the reliability is less than the effective threshold, it is determined that the received signal is invalid, and the ultrasonic signal is re-sent. When the reliability is greater than the update threshold, it is determined that the received signal waveform is highly consistent with the reference waveform. There is no need to update the reference waveform. When the reliability is between the effective threshold and the update threshold, it is determined that the received signal is valid. And the original reference waveform is replaced with the current received signal waveform to realize automatic tracking of the reference waveform. This paper analyzes the two kinds of waveform changes of ultrasonic received signal which may cause ultrasonic transit time error of one waveform period. The waveform changes are continuous envelope deformation and instantaneous envelope distortion. The change of gas flow rate, temperature and pressure will lead to the continuous change of received signal envelope. Spike pulses, random signals and periodic interference may cause instantaneous envelope distortion of the ultrasonic received signal. The instantaneous envelope distortion can be divided into three cases, severe distortion of the main peak, slight distortion of the main peak and non-main peak distortion. The experimental results show that under the influence of different flow velocity, temperature, pressure and noise, the relative error of ultrasonic gas flowmeter is less than ±1.0%. The results meet the measurement requirement of precision level 1.0. The automatic tracking method of reference waveform provides a guarantee for the accuracy and reliability of flow measurement.
-
图 2 不同流速下超声波接收信号包络分布
Figure 2. Envelope distribution of ultrasonic signals at different velocity
图 3 不同温度下超声波接收信号包络分布
Figure 3. Envelope distribution of ultrasonic signals at different temperature
图 4 不同压力下超声波接收信号包络分布
Figure 4. Envelope distribution of ultrasonic signals at different pressure
表 1 不同流速下流量计试验数据
Table 1. Experimental data of flowmeter at different velocity
参考流速/
(m·s−1)参考流量/
(m3·h−1)实测流量/
(m3·h−1)相对
误差/%可信度
最小值参考波形 0 0 0 0 0.97 未替换 0.500 56.55 56.579 0.37 0.91 未替换 0.986 111.56 112.029 0.42 0.86 未替换 2.990 338.21 340.003 0.53 0.81 未替换 7.986 903.19 909.693 0.72 0.71 替换过 11.971 1 353.90 1 357.982 0.30 0.67 替换过 20.914 2 365.37 2 357.091 −0.35 0.64 替换过 30.605 3 461.40 3 431.632 −0.86 0.63 替换过 
下载: 导出CSV
表 2 不同噪声影响下流量计试验数据
Table 2. Experimental data of flowmeter at different noise
噪声
类型参考流量/
(m3·h−1)实测流量/
(m3·h−1)相对
误差/%可信度
最小值参考
波形无噪声 111.56 112.029 0.42 0.86 未替换 噪声① 111.56 112.102 0.49 0.82 未替换 噪声② 111.56 112.113 0.50 0.81 未替换 噪声③ 111.56 112.108 0.49 0.76 替换过 噪声④ 111.56 112.201 0.57 0.73 替换过 噪声⑤ 111.56 112.123 0.50 0.75 替换过 噪声⑥ 111.56 112.216 0.58 0.63 替换过 噪声⑦ 111.56 112.413 0.76 0.52 失效过
下载: 导出CSV
表 3 不同温度下流量计试验数据
Table 3. Experimental data of flowmeter at different temperature
温度/℃ 可信度
最小值参考
波形温度/℃ 可信度
最小值参考
波形−20 0.97 未替换 30 0.78 替换过 −10 0.90 未替换 40 0.75 替换过 0 0.86 未替换 50 0.74 替换过 10 0.83 未替换 60 0.71 替换过 20 0.81 未替换
下载: 导出CSV
表 4 不同压力下流量计试验数据
Table 4. Experimental data of flowmeter at different pressure
压力/kPa 可信度最小值 参考波形 压力/kPa 可信度最小值 参考波形 40 0.75 替换过 90 0.86 未替换 50 0.76 替换过 100 0.91 未替换 60 0.79 替换过 125 0.91 未替换 70 0.81 未替换 150 0.91 未替换 80 0.83 未替换
下载: 导出CSV
-
[1] 陈超. 家用超声波燃气表系统设计[D]. 宁波: 宁波大学, 2019.CHEN Chao. Household ultrasonic gas meter system design[D]. Ningbo: Ningbo University, 2019. [2] 唐晓宇,张宏建,谢翔,等. 多声道超声波气体流量计声平面安装角度对测量影响的模型仿真和实验研究[J]. 中南大学学报(自然科学版),2017,48(7):1923-1929.TANG Xiaoyu,ZHANG Hongjian,XIE Xiang,et al. Model simulation and experimental research of acoustic-plane installation angle of multi-path ultrasonic gas flowmeter[J]. Journal of Central South University(Science and Technology),2017,48(7):1923-1929. [3] 张志君,祝飘霞,李跃忠,等. 超声气体流量计换能器安装角度对流量测量影响研究[J]. 电子测试,2020(13):53-55,46. doi: 10.3969/j.issn.1000-8519.2020.13.020ZHANG Zhijun,ZHU Piaoxia,LI Yuezhong,et al. Research on the influence of installation angle of ultrasonic gas flowmeter transducer on flow measurement[J]. Electronic Test,2020(13):53-55,46. doi: 10.3969/j.issn.1000-8519.2020.13.020 [4] 章涛,赵伟国,章圣意. 气体超声流量计回波信号的自适应阈值法研究[J]. 传感技术学报,2018,31(12):1853-1857.ZHANG Tao,ZHAO Weiguo,ZHANG Shengyi. The self-adaptive threshold method of echo signal for gas ultrasonic flowmeter[J]. Chinese Journal of Sensors and Actuators,2018,31(12):1853-1857. [5] 邵欣,韩思奇,檀盼龙,等. 超声波气体流量计检测精度影响因素分析[J]. 液压与气动,2018,42(9):80-86. doi: 10.11832/j.issn.1000-4858.2018.09.014SHAO Xin,HAN Siqi,TAN Panlong,et al. Factors affecting detection accuracy of ultrasonic gas flow meter[J]. Chinese Hydraulics & Pneumatics,2018,42(9):80-86. doi: 10.11832/j.issn.1000-4858.2018.09.014 [6] 方泽华. 基于智能拟合算法的超声波形起振点判定方法研究[D]. 杭州: 浙江大学, 2018.FANG Zehua. Research on judgment method of ultrasonic signal onest based on intelligent fitting algorithm[D]. Hangzhou: Zhejiang University, 2018. [7] 原佳豪. 基于编码激发的气体超声波流量计信号处理方法研究[D]. 杭州: 浙江大学, 2019.YUAN Jiahao. Research on signal processing method of gas ultrasonic flowmeter based on coded excitation[D]. Hangzhou: Zhejiang University, 2019. [8] 刘博韬. 噪音对超声流量计计量性能的影响及其改进措施[J]. 石油工业技术监督,2020,36(4):25-28,36. doi: 10.3969/j.issn.1004-1346.2020.04.008LIU Botao. Influence of noise on measurement performance of ultrasonic flowmeter and its improvement measures[J]. Technology Supervision in Petroleum Industry,2020,36(4):25-28,36. doi: 10.3969/j.issn.1004-1346.2020.04.008 [9] 诸葛晶昌,吴军,詹湘琳,等. 基于自适应小波去噪法的精密超声波测距方法[J]. 吉林大学学报(工学版),2017,47(4):1301-1307.ZHUGE Jingchang,WU Jun,ZHAN Xianglin,et al. Precise ultrasonic ranging method based on self-adaptive wavelet de-noising[J]. Journal of Jilin University(Engineering and Technology Edition),2017,47(4):1301-1307. [10] 季涛. 时差法多声道气体超声波流量计的研究[D]. 杭州: 浙江大学, 2017.JI Tao. Research on transit-time technique based on multipath ultrasonic gas flowmeter[D]. Hangzhou: Zhejiang University, 2017. [11] 鲁克华. 基于分段包络互相关算法的气体超声波流量计研究[D]. 杭州: 浙江大学, 2019.LU Kehua. Research of gas ultrasonic flowmeter based on cross-correlation algorithm of piecewise envelope[D]. Hangzhou: Zhejiang University, 2019. [12] 杨奉利. 智能超声波气体流量计的研制[D]. 杭州: 中国计量大学, 2018.YANG Fengli. Development of smart ultrasonic gas flowmeter[D]. Hangzhou: China Jiliang University, 2018. [13] 马超超. 基于时差法的双声道气体超声波流量计的研制[D]. 杭州: 中国计量大学, 2017.MA Chaochao. Development of gas ultrasonic flowmeter with double channel based on time difference method[D]. Hangzhou: China Jiliang University, 2017. [14] 汤士桢. 时差法互相关气体超声波流量计低流速计算及参考波形研究[D]. 杭州: 浙江大学, 2018.TANG Shizhen. Researches on low flow rate calculation and reference wave of time difference method and cross-correlation ultrasonic gas flowmeter[D]. Hangzhou: Zhejiang University, 2018. [15] 赵炜炜. 气体超声流量计电磁兼容设计与研究[D]. 杭州: 浙江大学, 2017.ZHAO Weiwei. Electro magnetic compatibility（EMC） design and research of ultrasonic gas flowmeter[D]. Hangzhou: Zhejiang University, 2017. [16] BAI Sizhong, ZHANG Jiayi, WANG Xuan, et al. A method to solve the periodic deviation in cross-correlation measurement of ultrasonic echo signals[C]//2nd International Conference on Frontiers of Sensors Technologies, Shenzhen, 2017: 358-362. [17] 王艺林. 气体超声波流量计高压驱动与信号处理技术研究[D]. 杭州: 浙江大学, 2019.WANG Yilin. Research on high voltage drive and signal processing technology of ultrasonic gas flowmeter[D]. Hangzhou: Zhejiang University, 2019. [18] 陈建,孙晓颖,林琳,等. 基于单周期互相关滤波的超声波TOF检测方法[J]. 仪器仪表学报,2014,35(3):664-669.CHEN Jian,SUN Xiaoying,LIN Lin,et al. Accurate ultrasonic TOF measurement method based on monocycle cross-correlation filtering[J]. Chinese Journal of Scientific Instrument,2014,35(3):664-669. [19] 贾佳,谷立臣. 基于超声流量计的包络互相关时延理论及仿真[J]. 自动化仪表,2012,33(7):53-55. doi: 10.3969/j.issn.1000-0380.2012.07.015JIA Jia,GU Lichen. Envelope correlation delay theory and simulation for ultrasonic flow meter[J]. Process Automation Instrumentation,2012,33(7):53-55. doi: 10.3969/j.issn.1000-0380.2012.07.015 -
点击查看大图
图(6) / 表(4)
计量
- 文章访问数: 240
- HTML全文浏览量: 36
- PDF下载量: 23
- 被引次数: 0
