多声道超声波流量计的设计与实验研究

发布时间：2018-09-04 19:11

【摘要】：流程工业的三大测量要素分别为流量、温度与压力。随着国内西气东输项目的进展、城市天然气管道化的建设、油田民用天然气商品化政策的实施、化工生产原料流量的计量的需求、以及供水管道项目的日益增加使得流量计量仪表得到更广泛的应用,并在国民经济的发展中逐步起到不可替代的作用。超声波流量测量技术是一种应运而生的新技术,它利用超声波信号在流体中传播时所载流体的流速信息来测量流体流量,具有测量精度高、低流速性好、压力损失小、适用范围广、测量范围大等特点。本文设计了一种基于嵌入式ARM Cortex-M3内核的STM32L超低功耗多声道超声波液体流量智能计量仪表,并开展了如下几个方面的研究工作:(1)通过查阅大量相关文献和资料,根据国内外研究现状,分析超声波在介质中的传播特性,并研究超声波换能器的工作原理,此外,详细研究分析不同种类超声波流量计的测量原理,并比较其优势和劣势,分辨其适用场合,最后,根据设计要求,提出应用时差法来实现超声波流量测量的设计方案。(2)在低功耗要求的前提下,提出基于嵌入式ARM Cortex-M3内核的STM32L+TDC-GP22的设计方案,提出多声道超声波测量计的硬件电路的总体设计方案,根据各个模块的技术要求,选择芯片设计电路,并应用一定的抗干扰措施来提高测量精度。此外,通过多通道的回波信号自动增益调节和误差修正算法来降低测量误差,实现液体流量的高精度计量、存储。并通过虚拟仪器技术实现数据在线监控等功能。本文设计的多声道超声波流量计具有测量介质可选、声道数可选、计量精度高、功能可扩展性强、超低功耗等优点。(3)软件设计方面,采用模块化设计方法,将整个系统分为4个模块。提出软件设计的总体流程图,并分别设计时间测量程序,超声波的发射、接收程序,中断程序。分析了多声道超声波流量计的流量算法以及多声道测量计算程序,从而完成对整个硬件系统的控制,并实现数据的处理和显示等功能。(4)基于硬件电路设计和软件控制流程,搭建基于虚拟仪器的实验平台,通过虚拟仪器技术实现数据在线监控等功能。对所设计的多声道超声波流量计进行实验测试。通过分析实验结果,验证本文所设计的超声波流量计的正确性以及可行性,证明设计方案具有更高的测量精度。
[Abstract]:The three major measurement elements of the process industry are flow rate, temperature and pressure. With the progress of the West-to-East Gas Transmission Project in China, the construction of urban natural gas pipeline, the implementation of the commercial gas policy for civil oil fields, and the demand for the metering of raw material flow in chemical production, And the increasing number of water supply pipeline projects make the flow meter more widely used and gradually play an irreplaceable role in the development of national economy. Ultrasonic flow measurement is a new technology, which uses the velocity information of the fluid when the ultrasonic signal propagates in the fluid to measure the flow rate of the fluid. It has the advantages of high measuring accuracy, good low velocity and low pressure loss. Wide scope of application and wide range of measurement. In this paper, an intelligent measurement instrument of STM32L ultra-low power multi-channel ultrasonic liquid flow based on embedded ARM Cortex-M3 kernel is designed, and the following research work is carried out: (1) through consulting a lot of relevant literature and materials, According to the present research situation at home and abroad, the characteristics of ultrasonic wave propagation in medium are analyzed, and the working principle of ultrasonic transducer is studied. In addition, the measuring principle of different kinds of ultrasonic Flowmeter is analyzed in detail, and its advantages and disadvantages are compared. Finally, according to the design requirements, a design scheme of ultrasonic flow measurement based on the time difference method is proposed. (2) based on the requirement of low power consumption, the design scheme of STM32L TDC-GP22 based on embedded ARM Cortex-M3 kernel is proposed. The overall design scheme of the hardware circuit of the multi-channel ultrasonic meter is presented. According to the technical requirements of each module, the chip design circuit is selected, and some anti-interference measures are applied to improve the measuring accuracy. In addition, the multi-channel echo signal automatic gain adjustment and error correction algorithm are used to reduce the measurement error and realize the high precision measurement and storage of liquid flow. And through virtual instrument technology to realize data online monitoring and other functions. The multi-channel ultrasonic Flowmeter designed in this paper has the advantages of the choice of measuring medium, the number of sound channels, the high accuracy of measurement, the strong expansibility of function and the ultra-low power consumption. (3) in software design, the modular design method is used. The whole system is divided into four modules. The general flow chart of software design is presented, and time measuring program, ultrasonic transmitting program, receiving program and interrupt program are designed respectively. This paper analyzes the flow algorithm of multi-channel ultrasonic Flowmeter and the calculation program of multi-channel measurement, so as to complete the control of the whole hardware system and realize the functions of data processing and display. (4) based on the hardware circuit design and software control flow, The experiment platform based on virtual instrument is built, and the function of data online monitoring is realized through virtual instrument technology. The designed multi-channel ultrasonic Flowmeter is tested experimentally. Through the analysis of the experimental results, the correctness and feasibility of the ultrasonic Flowmeter designed in this paper are verified, and it is proved that the design scheme has higher measuring accuracy.
【学位授予单位】：河南工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TH814.92

【参考文献】