可自动控温的气敏（材料）测试系统的研制

发布时间：2018-01-06 05:23

  本文关键词：可自动控温的气敏（材料）测试系统的研制　出处：《吉林大学》2017年硕士论文　论文类型：学位论文

  更多相关文章： 气敏测试系统 阻值快速测量 温度测量 PID控制 阶梯式升温

【摘要】：随着科学的发展、物联网和人工智能时代的到来,生活中的气敏传感器朝着检测更全面、测量更准确的方向发展。为了有效地发挥气敏材料形态、形貌、和结构对气敏特性的影响,进一步提高半导体气敏传感器的灵敏度,本课题组申请了国家自然科学基金项目《以三维网络泡沫镍为载体的多孔P-N异质接触结构的制备及其气敏特性研究》(批准号61474056),由于传统的测试系统无法测试以泡沫镍为载体的气敏材料,我们设计了与之相匹配的、新型的气体敏感特性测试系统,并且有针对性地设计了在较宽的电阻测量范围下,能够快速测量的方法。该测试系统不仅能够测试以多孔材料为基底的气敏材料,还能测试粉末或薄膜状气敏材料,同时对温度也能够精确地测量,可使温度按阶梯式上升,使材料测试过程的操作更智能化。该测试系统包括测试模拟环境、硬件电路和上位机软件三个部分。测试模拟环境主要包括气箱的制作、测试探针的定制和测试台的组建。通过使用定制的小弹力探针和微调架,达到保护多孔材料结构的目的。硬件电路以嵌入式处理器ARM7为核心,主要分为电阻测量模块,温度测量模块和加热模块。气敏材料的工作温度应该是一个精确测量值,所以相比以往的大多数测试系统,本设计增加了一个测温模块,能够实时检测气敏材料的温度;为了实现阻值的快速测量,电阻测量模块的设计使用了阻值范围交叉式分档测量的方法,适用于灵敏度在10000以下的气敏材料的测试;加热模块由微控制器内部集成的DA转换器和外围的功率运算放大器组成,形成数控电压源,结合PID控制算法,可使加热装置的温度按阶梯式上升。本设计研究了气敏材料的测试过程,使用PyQt软件制作上位机界面,让测试的操作过程变得更智能化。系统程序上分为两种工作模式:工作模式一和工作模式二。工作模式一适用于寻求气敏材料的最佳工作温度点,可阶梯式升温,测试的整个过程不再需要人工调整;工作模式二适用于气敏材料的响应恢复特性测试,测试过程中不换电阻档位,实现阻值的快速测量。两种工作模式能够大大地节省人力资源。本测试系统能够对以多孔材料为基底的气敏材料进行测试;使用阻值范围交叉式分档测量的方法,测量范围是1Ω~500MΩ,误差率在2%以下,电阻值在10MΩ以上测量速度仍能到达10次/秒;使用常规PID和模糊PID相结合的控制算法,温度控制更加快速、精确;温度的测量范围是0~500℃,误差率在1%以下;为新型气敏材料的开发提供了一个可靠的测试手段,具有一定的实际意义。
[Abstract]:With the development of science, the arrival of the era of Internet of things and artificial intelligence, the gas sensors in life are developing towards more comprehensive detection and more accurate measurement. The influence of the structure and the structure on the gas sensitivity of the semiconductor gas sensor can be further improved. The project of National Natural Science Foundation of China (Grant No. 61474056) has been applied for the preparation of porous P-N heterocontact structure with three dimensional network nickel foam as the carrier and its gas sensing characteristics. Because the traditional testing system can not test the gas sensing material with nickel foam as the carrier, we have designed a new type of gas sensitivity testing system. The method of rapid measurement is designed in a wide range of resistance measurement. The system can not only test the gas sensing material based on porous material. It can also test the powder or thin film gas sensing material, at the same time, the temperature can be accurately measured, which can make the temperature rise step by step and make the operation of the material test process more intelligent. The testing system includes the test simulation environment. The test simulation environment mainly includes the manufacture of air box, the customization of test probe and the construction of test bench. Through the use of customized small elastic probe and micro-adjusting frame. In order to protect the porous material structure, the hardware circuit is mainly divided into resistance measurement module with embedded processor ARM7 as the core. Temperature measurement module and heating module. The working temperature of gas sensing material should be an accurate measurement value, so compared with most previous test systems, this design adds a temperature measurement module. It can detect the temperature of gas sensing material in real time. In order to realize the rapid measurement of the resistance value, the resistance measurement module is designed by using the method of cross step measurement in the range of resistance, which is suitable for the test of gas sensing material with sensitivity below 10000. The heating module consists of a DA converter integrated in the microcontroller and a peripheral power operational amplifier to form a numerical control voltage source, combined with the PID control algorithm. The temperature of heating device can be increased by step. The test process of gas sensing material is studied, and the upper computer interface is made with PyQt software. The operating process of the test becomes more intelligent. The system is divided into two working modes: mode 1 and mode 2. Mode 1 is suitable for seeking the best working temperature point of gas sensing material. Stepwise heating, the whole process of testing no longer need to be manually adjusted; The second mode is suitable for the test of the gas sensing material's response recovery characteristic, and the resistance gear is not changed during the testing process. The two working modes can save human resource greatly. This testing system can test the gas sensing material based on porous material. By using the method of cross step measurement in the range of resistance, the measuring range is 1 惟 / 500M 惟, the error rate is below 2%, and the measuring speed of resistance value above 10m 惟 can still reach 10 times per second. Using the conventional PID and fuzzy PID control algorithm, the temperature control is faster and more accurate. The temperature measurement range is 0 ~ 500 鈩，

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