Vibration Numerical Simulation Of New Quartz Piezoelectric Sensor Under Complex Conditions And Research Of Pattern Recognition

According to the principle of Quartz Crystal Microbalance(QCM), we have designed a new polymer quartz piezoelectric sensor applied in the detection of volatile gas. For the sensor, the AT-cut type semiconductor with piezoelectric effect was used as base, the "vacuum electron beam dispersion (EBD) coating technology" was used to evaporate the polymer coating on the surface of the substrate. The sensor whose structure was composed of polymer coating/quartz crystal plate/polymer coating was obtained. Especially, the polymer coating has the function of physical absorption and desorption to volatile gas. By analyzing the composition of the Chinese spirits’volatile gas, choosing polymer materials and studying of the preparation technology, we prepared the new sensors and the sensor array was composed for distinguishing Chinese spirits. Through designing of the back-end circuit system and the pneumatic transmission system reasonably, we obtained the new polymer quartz piezoelectric sensor system. For the characteristic information of Chinese spirits products collected by the system, we established a new pattern recognition system based on moving average and linear discriminates analysis(LDA), and the template data of Chinese spirits was obtained also, which help us to realize the purpose of distinguishing Chinese spirits.In the new polymer quartz piezoelectric sensor system, the new polymer quartz piezoelectric sensor with high sensitivity and the pattern recognition system which used in the sensor system are the most important. In application of the new polymer quartz piezoelectric sensor, there are phenomenon that the thickness of the film is not uniform, film has defects, surface of the quartz is easy to be affected with damp and susceptible to corrosion, etc, all of which seriously affect the sensitivity of the new sensor. Meanwhile, the existing pattern recognition algorithms can’t extract the data’s useful information effectively. For the above problems, this paper conducted a study in two aspects which contains the vibration analysis of the new polymer quartz piezoelectric sensor and the research of pattern recognition algorithms used in the classification and identification of Chinese spirits, trying to gain a new polymer quartz piezoelectric sensor with high sensitivity and the pattern recognition system effectively combined with the sensor system. Therefore, in this paper, the research includes:1) Comprehensively described present situation of the vibration analysis of the quartz piezoelectric sensor and the study of the pattern recognition system of the e-nose system. This paper pointed out that the gas information collection system based on gas sensor array and the back-end circuit system based on the pattern recognition, in the electronic nose, play a decisive role in the application of electronic nose and the accuracy of testing results.2) For the testing of Chinese spirits, this paper has optimized the design of the new type of polymer quartz piezoelectric sensor and developed the8-channel sensor array. Combining the basis of quartz piezoelectric sensor system and the back-end circuit system, we designed the new polymer quartz piezoelectric sensor system applied to the distinguishing of Chinese spirits.3) For the phenomenon that the thickness of the coating is not uniform, coating has defects, surface of the quartz is easy to be affected with damp and susceptible to corrosion, etc, this paper established a new mechanical model of polymer quartz piezoelectric sensor, considering the size of the coating defects, thickness of the coating with defects, humidity, the thickness of quartz’s corrosion layer, etc. Through modal analysis using ANSYS finite element software to the mechanical model, we extracted the related modal and frequency from the results of the modal analysis. By using the numerical method, this paper shows the principle of vibration frequency of quartz piezoelectric sensor influenced by the size of the coating defects, thickness of the coating with defects, humidity, the thickness of quartz’s corrosion layer, etc.4) For the frequency signals collected by new type of e-nose system which consists of8-channel sensor array and is applied to distinguish Chinese spirits, this paper used the least-square method to analyze the frequency signals and get the characteristic information of Chinese spirits. Through the study of various pattern recognition methods, we established the new pattern recognition system based on moving average and LDA, and gained the11kinds of template databases of Chinese spirits.This paper has deeply studied the vibration analysis of the new type of polymer quartz piezoelectric sensor and its application in distinguishing Chinese spirits through theory, experiment and numerical analysis. This research is an important part of the "research and application, in the field of food safety, of chemicals sensitive type of affinity polymer materials and piezoelectric sensor system" which is conducted by our team. And it plays a positive role for the development of the fields of piezoelectric sensor technology, e-nose technology and pattern recognition technology of our country.