【作者】 杨帆；

【导师】 徐军；

【作者基本信息】 哈尔滨理工大学 ， 控制工程（专业学位）， 2020， 硕士

【摘要】 湿度检测技术在气候监测、智能制造、智慧农业、航空航天等领域发挥着重要的作用。针对兆赫兹频率级别输出的石英晶体微天平(Quartz Crystal Microbalance,QCM)湿度传感器,虽然具有灵敏度高和响应速度快等优点,但存在体积大、功耗高、输出信号需要屏蔽缆线等问题。因此,本文通过对国内外技术现状和应用领域调研,提出以聚乙烯醇(Polyvinyl Alcohol,PVA)为湿敏材料,结合石英音叉谐振器,设计一种数字型湿度传感器,该传感器具有体积小、功耗低、灵敏度高等特点。本论文采用理论分析和实验验证相结合的方法进行传感器的研究与设计。首先,对石英音叉谐振器的工作机理进行阐述,在分析PVA材料与水分子感湿特性的基础上,将PVA涂覆在石英音叉臂的顶端,结合PVA对水分子吸附、脱附而导致石英音叉臂质量的微小变化,引起石英音叉谐振频率的偏移;根据石英音叉臂质量变化与石英音叉谐振频率偏移之间的湿敏特性,通过仿真建立传感器湿度频率特性关系曲线,完成湿度传感器机理的理论分析。其次,采用ABS外壳及松香树脂对传感器结构进行封装,完成传感器原型设计,同时将石英音叉谐振频率振荡和分频电路与微处理器相结合实现对湿度频率信号的检测,亦可通过网络节点单元完成湿度参数的换算和数据可视化系统的搭建。最后,搭建恒温恒湿测试系统对传感器进行标定。测试结果表明:在室温20℃、11.3%RH～75.4%RH的范围内,灵敏度约为1.14Hz/(%RH),非线性误差约为5%,湿滞误差13.8%,重复性误差4.9%,响应时间和恢复时间分别是60s和105s左右,具有良好的重复性。本文设计的基于聚乙烯醇材料石英音叉湿度传感系统可实现对湿度信号的检测,具有灵敏度高、稳定性好等特点,并可通过远程可视化的方式进行湿度参数的实时监测,从而对其它基于石英音叉谐振式传感器的设计和应用提供有意义的借鉴思路。更多还原

【Abstract】 Humidity detection technology plays an important role in climate monitoring,smart manufacturing,smart agriculture,aerospace and other fields.Quartz Crystal Microbalance(QCM)humidity sensor for megahertz frequency level output,although it has the advantages of high sensitivity and fast response speed,but it has a large volume,high power consumption,and the output signal requires a special shielded cable connection and other problems.Therefore,in this paper,by investigating the current state of technology and application fields at home and abroad,a polyvinyl humidity(Polyvinyl Alcohol,PVA)as a moisture sensitive material combined with a quartz tuning fork resonator is proposed to design a digital humidity sensor.The sensor has the characteristics of small size,low power consumption and high sensitivity.This paper uses a combination of theoretical analysis and experimental verification to research and design sensors.First,the working mechanism of the quartz tuning fork resonator is explained.Based on the analysis of the moisturesensing characteristics of the PVA material and water molecules,PVA is coated on the top of the quartz tuning fork arm,the water molecules are adsorbed and desorbed by PVA to cause a slight change in the quality of the tuning fork arm,and causes a shift in the resonance frequency of the quartz tuning fork.According to the humidity sensitivity characteristic between the change in the mass of the quartz tuning fork arm and the resonance frequency shift of the quartz tuning fork,a humidity humidity characteristic curve of the sensor is established through simulation to complete the humidity sensor mechanism Theoretical analysis.Secondly,the sensor structure is packaged by the ABS shell and rosin resin to complete the sensor prototype design,and the quartz frequency tuning fork resonance frequency oscillation and frequency division circuit is combined with the microprocessor to realize the detection of the humidity frequency signal,and the network node unit is used to complete the Conversion of humidity parameters and construction of data visualization system.Finally,the sensor was calibrated by setting up a constant temperature and humidity test system.The test results show that the sensor has a sensitivity of ab out 1.14 Hz /(%RH)in the range of 11.3% RH to 75.4% RH at a room temperature of 20 ° C.The non-linear error is about 5%,the hysteresis error is 13.8%,and the repeatability error is 4.9%,and the response time and recovery time are about 60 s and 105 s,which has good repeatability.The polyvinyl alcohol-based quartz tuning fork humidity sensor system designed in this paper can realize the detection of humidity signals,has the characteristics of high sensitivity,good stability,etc.,and can perform real-time monitoring of humidity parameters by remote visualization,it can provide meaningful reference for the design and application of other quartz tuning fork resonance sensors.更多还原