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| Study on Dynamic Threshold Method Based on Echo Similarity for Ultrasonic Gas Flow Meter |
| MA Ye-chi1,ZHAO Wei-guo1,ZHANG Sheng-yi2 |
1. College of Metrological and Measurement Engineering, China Jiliang University, Hangzhou, Zhejiang 310018, China
2. Zhejiang Cangnan Instrument Group Co., Ltd Cangnan, Cangnan, Zhejiang 325800, China |
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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%.
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Received: 10 August 2020
Published: 08 April 2022
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［1］张晓钟, 孟凡芹, 宋生奎. 基于神经网络的超声波轻质燃油质量流量测量方法研究 ［J］. 计量学报, 2017, 38 (2): 205-208.
Zhang X Z, Meng F Q, Song S K. The Ultrasonic Mass Flow Measurement Method of Light Fuel Based on the Artificial Neural Network Model ［J］. Acta Metrologica Sinica, 2017, 38 (2): 205-208.
［2］Zhou H L, Ji T, Wang R C, et al. Multipath Ultrasonic Gas Flow-meter Based on Multiple Reference Waves ［J］. Ultrasonics, 2017, 82: 145-152.
［3］Khyam M O, Ge S S, Li X D, et al. Highly Accurate Time-of-Flight Measurement Technique Based on Phase-correlation for Ultrasonic Ranging ［J］. IEEE Sensors Journal, 2016, 17 (2): 434-443.
［4］Zheng D D, Hou H R, Zhang T. Research and Realiza-tion of Ultrasonic Gas Flow Rate Measurement Based on Ultrasonic Exponential Model ［J］. Ultrasonics, 2016, 67: 112-119.
［5］Mu L B, Xu K J, Liu B, et al. Echo Signal Envelope Fitting based Signal Processing Method for Ultrasonic Gas Flowmeter ［J］. ISA Transactions, 2019, 89: 233-244.
［6］Hu L, Fang Z H, Qin L H, et al. Modelling of Received Ultrasonic Signals Based on Variable Frequency Analysis ［J］. Flow Measurement& Instrumentation, 2018, 65: 141-149.
［7］Zhen K L, Ma F H, Cui Y, et al. A Novel Method for Estimating Time of Flight of Ultrasonic Echoes through Short-time Fourier Transforms ［J］. Ultrasonic, 2020, 103: 106104.
［8］ 陈洁, 余诗诗, 李斌, 等. 基于双阈值比较法超声波流量计信号处理 ［J］. 电子测量与仪器学, 2013, 27 (11): 1024-1033.
Chen J, Yu S S, Li B, et al. Signal Processing Based on Dual-Threshold of Ultrasonic Flow Meter ［J］. Journal of Electronic Measurement and Instrument, 2013, 27 (11): 1024-1033.
［9］Fang Z H, Hu L, Mao K, et al. Similarity Judgement based Double-Threshold Method for Time-of-Flight Dete-rmination in an Ultrasonic Gas Flowmeter ［J］. IEEE Transactions on Instrumentation & Measurement, 2018, 67 (1): 1-9.
［10］ Chen Q, Li W H, Wu J T, et al. Realization of a Multipath Ultrasonic Gas Flow-meter Based on Transit-time Technique ［J］. Ultrasonics, 2014, 54 (1): 285-290.
［11］Tobias L. Zero Detection of an Ultrasonic Signal with Variable Threshold Value: US7543508 B2 ［P］. 2008-08-14.
［12］ 穆立彬, 徐科军, 刘博, 等. 基于可变阈值和过零检测的四声道气体超声波流量变送器 ［J］. 计量学报, 2019, 40 (2): 266-271.
Mu L B, Xu K J, Liu B, et al. Development of Four-channel Ultrasonic Gas Flow Transmitter Based on Variable Threshold and Zero-crossing Detection ［J］. Acta Metrologica Sinica, 2019, 40 (2): 266-271.
［13］Zhu W J, Xu K J, Fang M, et al. Variable Ratio Threshold and Zero-crossing Detectionbased on Signal Processing Method for Ultra-sonic Gas Flow Meter ［J］. Measurement, 2017, 103: 343-352.
［14］ 方敏, 徐科军, 汪伟, 等. 基于FPGA和DSP的气体超声流量计驱动和数字信号处理系统 ［J］. 计量学报, 2017, 38 (2): 200-204.
Fang M, Xu K J, Wang W, et al. A Driving and Digital Signal Processing System of Ultrasonic Gas Flow Meter Based on FPGA&DSP ［J］. Acta Metrologica Sinica, 2017, 38 (2): 200-204.
［15］ 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 T, Zhao W G, Zhang S Y. The Self-Adaptive Threshold Method of Echo Signal for Gas Ultrasonic Flowmeter ［J］. Journal of Transduction Technology, 2018, 31 (12): 1853-1857.
［16］ 郑娆, 郝金玲, 王耘. 基于欧式距离的化合物作用靶点识别方法研究 ［J］. 计算机与应用化学, 2012, 29 (8): 943-946.
Zheng R, Hao J L, Wang Y. Chemical Target Iden-tification Method based on Euclidean Distance ［J］. Computer and Applied Chemistry, 2012, 29 (8): 943-946. |
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2022, Vol. 43 
