磁致伸缩水位传感器与灌区渠道水位流量采集系统研究

发布时间：2018-06-21 13:01

本文选题：灌区 + 磁致伸缩传感器　；参考：《西北农林科技大学》2017年硕士论文

【摘要】：随着全球工农业生产和城市的发展,水资源紧缺已经是一个全球性的问题。我国的农业灌溉用水占据全国总用水量的60%以上,但是灌溉水利用系数平均不足0.5,为了实现灌区节约用水和科学用水,对用水进行精确测量显得尤为重要。传统的测量工具已经无法满足灌区对实时用水情况的需要,因此对水情的自动化测量成为一种趋势。本文在对灌区水位流量测量技术的发展、研究现状的分析基础上,结合目前灌区的特点,设计开发了高精度、低成本的磁致伸缩水位传感器,并基于磁致伸缩水位传感器研究了灌区渠道水位流量采集系统。取得主要进展如下:(1)磁致伸缩水位传感器开发。根据灌区渠道水位测量要求,设计传感器头部外壳、金属探测杆外形、活动浮子形状和大小、线圈骨架等的机械机构。通过对激励脉冲参数的分析,确定选用方波单脉冲,并确定了脉冲的幅值、宽度等参数,最终采用单片机引脚模拟激励脉冲、电荷泵升压电路和场效管电路组成激励放大电路。针对微弱回波信号,通过对回波检测线圈结构和回波信号的分析,最终确定采用AD8420放大器和比较整形电路组成回波信号处理电路,将回波信号调制成幅值为5V的方波信号。基于灌区水位测量精度的要求,采用D触发器、与非门和单片机构成计时电路,将激励脉冲与回波信号之间时间间隔调制成PWM波形,便于准确计时。最后设计单片机外围电路。完成各个模块的硬件电路后,采用C语言编写传感器程序,实现水位测量。本传感器具有精度高、功耗低、稳定可靠的特点。(2)灌区渠道水位流量采集系统。选用梯形渠道作为本研究的典型渠道,利用自主研制的磁致伸缩水位传感器作为灌区渠道水位采集传感器,通过GPRS无线传输设备WG-8010 GPRS DTU将水位信息发送到远程云服务,并在远程云服务器上根据拟合的水位-流量公式计算出相应的流量值,将数据保存到云服务的My SQL数据库中,同时设计数据采集器将传感器数据进行本地SD卡存储。为方便管理人员随时登录查看水情趋势和下载历史数据,设计基于Linux云服务器的灌区渠道水位流量采集系统网站。本文综合应用了传感器技术、GPRS无线传输技术、My SQL技术和云服务器技术,设计开发了一套能够远程实时监测灌区水位流量的系统。经过整体测试证实,系统运行稳定可靠,测量精度高,成本低,能适用于灌区渠道水位的测量,拥有比较高的应用价值。
[Abstract]:With the development of global agriculture and industry, water shortage is a global problem. Agricultural irrigation water in China accounts for more than 60% of the total water consumption in China, but the average utilization coefficient of irrigation water is less than 0.5. In order to save water and use water scientifically, it is very important to measure water accurately. The traditional measurement tools can not meet the need of real-time water use in irrigation areas, so the automatic measurement of water regime has become a trend. Based on the development of water level and discharge measurement technology in irrigation area and the analysis of the present situation, a magnetostrictive water level sensor with high precision and low cost is designed and developed based on the characteristics of the irrigation area at present. Based on the magnetostrictive water level sensor, the collection system of water level and discharge in irrigation area is studied. The main progress is as follows: 1) Development of magnetostrictive water level sensor. According to the requirement of water level measurement in irrigation area, the mechanical mechanism of sensor head shell, shape of metal probe rod, shape and size of floating float, coil skeleton and so on is designed. Through the analysis of the excitation pulse parameters, the square wave single pulse is selected, and the amplitude and width of the pulse are determined. Finally, the single chip microcomputer pin is used to simulate the excitation pulse, the charge pump boost circuit and the field effect tube circuit are used to compose the excitation and amplification circuit. Based on the analysis of the structure of the echo detection coil and the echo signal, the AD8420 amplifier and the comparison shaping circuit are used to form the echo signal processing circuit. The echo signal is modulated into the square wave signal with the amplitude of 5 V. Based on the requirement of precision of water level measurement in irrigation area, D flip-flop, non-gate and single-chip microcomputer are used to compose timing circuit. The time interval between excitation pulse and echo signal is modulated into PWM waveform, which is convenient for accurate timing. Finally, the peripheral circuit of single chip microcomputer is designed. After the completion of the hardware circuit of each module, C language is used to write the sensor program to realize water level measurement. The sensor has the characteristics of high precision, low power consumption and reliable stability. The trapezoidal channel is selected as the typical channel in this study, the magnetostrictive water level sensor developed by ourselves is used as the channel water level acquisition sensor in irrigation area, and the water level information is sent to the remote cloud service through GPRS wireless transmission device WG-8010 GPRS DTU. The corresponding flow value is calculated on the remote cloud server according to the fitted water-discharge formula, and the data is saved to my SQL database of the cloud service. At the same time, a data collector is designed to store the sensor data on the local SD card. In order to facilitate managers to log in and view water regime trends and download historical data at any time, a water level and discharge collection system website for irrigation district based on Linux cloud server is designed. In this paper, the sensor technology, GPRS wireless transmission technology, my SQL technology and cloud server technology are used to design and develop a remote real-time monitoring system for water level and discharge in irrigation area. It is proved by the whole test that the system is stable and reliable, with high measuring precision and low cost. It can be applied to the measurement of water level in irrigation area and has high application value.
【学位授予单位】：西北农林科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S274.4;TP212

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