Research On Comprehensive Testing System For PZT Piezoelectric Ceramics And Applications

PZT(lead zirconate titanate)is a kind of functional ceramics that have good piezoelectric properties,has been extensively applied in high-tech fields such as telecommunication,medical science,military and aerospace etc.The characteristic parameters of PZT are important to its preparation,theoretical research and practical application.With the further development of PZT materials and PZT application devices,the research on measurement about the characteristic parameters of PZT and its application devices is also more important.Concentrating on the testing of PZT materials and its applications,a comprehensive testing system based on admittance circle method is designed.The main research contents are as follows:Firstly,the existing PZT test methods and test systems were studied.The admittance circle method is chosen as the testing method of this system,and the advantages and disadvantage of existing test systems is summarized.And the PZT test method based on admittance circle is introduced in detail.On the basis of this,the overall scheme of the system is determined which is composed of admittance data detection board and client software platform.Secondly,the technical indicators and the overall framework of the admittance data detection board are determined according to the requirements of the test method.Then the hardware design of the admittance data detection board is completed which mainly includes test signal generation module,test signal filtering module,test signal power amplification module and detected signal sampling module.Further more,a communication protocols is formulated,and the software design of the admittance data detection board is completed.Thirdly,the data processing methods of the system is studied,including parameter estimation method of the detected signal and fitting method of admittance circle.Three parameter estimation methods are introduced and simulated,including superposition correlation function method,fast Fourier transform method and three-parameter estimation of sinusoidal signal method.The simulation results indicate that the fast Fourier transform method has the best estimation effect.Then,Three admittance circle fitting methods are introduced and simulated,including average method,weighted average method and least squares method based on the Kasa objective function.The simulation results show that the least squares method based on Kasa objective function has the best fitting effect.Fourthly,the requirements of the software platform are analyzed,and the overall framework of the client software platform is designed.Then the data to be managed by the client software platform is clarified,and the data relationship structure model is designed.On these basis,the client software platform is achieved by using Qt5.Finally,a experimental platform of the comprehensive testing system is built.Then the system is verified by some experiments,including the test signal generation experiment and the PZT test experiment,and the errors of the system are analyzed.Results of experiments show that test signal meets the technical indicators and the system has high accuracy when testing high Q_m PZT.