【作者】 吴燕康；

【导师】 孙斌； 朱家顺；

【作者基本信息】 中国计量大学 ， 工程硕士（专业学位）， 2018， 硕士

【摘要】 超声波进行管道流体温度测量具有非接触测量、快速响应、测量范围宽等优点,特别适合大管径和高危险性流体温度的测量。课题采用FPGA+STM32单片机的硬件电路结构设计了一种基于时差法的超声波管道流体温度测量系统,提高超声波在介质中传播时间的测量精度是提高系统测量精度的关键,主要研究内容如下:1、研究了不同超声波温度测量方法特别是时差法温度测量原理;对超声波在液体介质中的传播特性及超声波换能器的工作原理进行了深入研究,并对超声波换能器进行设计和安装。2、根据所设计的超声波换能器的特性,设计高性能超声波换能器匹配电路;系统采用FPGA和单片机协同工作的方式,以FPGA作为超声波信号发射和采集的控制芯片,采用Verilog HDL硬件描述语言及大量IP核进行FPGA软件设计;以STM32单片机作为信号处理和人机交互电路的控制芯片。3、设计最大特征波提取算法和精确计算传播时间终点时刻的直线插补算法,超声波传播时间的测量精度达到纳秒级别。4、对系统的各个功能模块进行仿真、调试,在不同的实验平台下分别开展静态液体介质和管道内流动液体介质的温度测量实验,并对测量结果进行误差分析和不确定度评定,结果表明所设计的系统满足高精度快速测温的设计目标。更多还原

【Abstract】 Ultrasonic piping fluid temperature measurement with the advantages of non-contact measurement,fast response,wide measurement range,etc.,and it is particularly suitable to measure the temperature of large diameter and high dangerous fluid.An ultrasonic pipeline fluid temperature measurement system based on time difference method is designed by FPGA + STM32 microcontroller hardware circuit structure,improving the the measurement accuracy of ultrasonic propagation time in the media is the key to improve the accuracy of the system measurement.The main research contents are as follows:1.Various ultrasonic temperature measurement methods are studied,especially the time difference method;the propagation characteristics of ultrasonic wave in liquid medium and the working principle of ultrasonic transducer are studied in detail,and the ultrasonic transducer is designed and installed.2.According to the characteristics of the designed ultrasonic transducer,the ultrasonic transducer matching circuit with good performance is designed;the system uses the way of FPGA and single chip working together.FPGA is used as the control chip for transmitting and collecting ultrasonic signals,and Verilog HDL hardware description language and a large number of IP cores are used to design FPGA software;STM32 series microcontroller is used as the control chip of signal processing and man-machine interaction circuit.3.Design the maximum feature wave extraction algorithm and the linear interpolation algorithm for accurate calculation of the end of propagation time,the measurement accuracy of the ultrasonic propagation time reaches the nanosecond level.4.Each functional module is simulated and debugged,and under different experimental platforms,the temperature measurement experiments of static liquid medium and liquid medium in the pipeline were carried out.The error analysis and uncertainty evaluation of the measurement results were carried out.The system meets the design goals of high-precision rapid temperature measurement.更多还原