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The Measurement For Dynamic Characteristics Of Piezoelectric Microcantilever

Posted on:2011-12-25Degree:MasterType:Thesis
Country:ChinaCandidate:G L YaoFull Text:PDF
GTID:2178330332961373Subject:Circuits and Systems
Abstract/Summary:PDF Full Text Request
The measurement of the dynamic characteristics of micro-structure is a big challenge, because MEMS devices continue to shrink the size and to improve the frequency. As a part of MEMS devices, the dynamic characteristics measurement of piezoelectric micro-cantilever has been widly concerned about; The measurement of the dynamic characteristics can provide the basis for optimizing the structure design. The structual properties and the material properties were tested in this paper. The execute-sensor itegrated method and the piezoelectric beam impedance analysed method are mainly researched in this paper.In the material properties testing, in order to deter the piezoelectric properties of the measured beam, measurement system based on the LabVIEW is designed in this paper. The system can determine whether the hysteresis loop is saturation, it can save data to your computer, and can modify the actual parameters to achieve the flexibility of the measurement system.In the structural properties testing, the electromechanical coupling and mechanical vibration methods were proposed in this paper. The electromechanical coupling method was studied mainly. First, the execute-sensor method was used to measure the dynamic characteristics of bimorph. After the excitation signal was applied to one piece of the bimorph, the charge of anthor piece can be measured to characterise the piezoelectric beam.To measure the common piezoelectric beam, the virtual instrument based on piezoelectric beam impedance analyzer is designed in this paper. With the auxiliary circuit composed of the precision series resistor and the the piezoelectric beam, the impedance of the piezoeletric beam can be calculated by extracting the current. The dynamic characteristics of PZT cantilever can be got from the real part of the complex impedance.In the mechanical electrical measurement, For the large size of the piezoelectric cantilever, eddy current displacement meter is used to measure the vibration of the free end of the piezoelectric beams, but the micro-eddy current displacement meter can not be used for the micro-beam measurement, also has some limitations. In order to detect he dynamic characteristics more intuitive, we analyzes the basic principle of optical measurement methods; We can qualitative calibrate the dynamic characteristics of piezoelectric micro-cantilever beam by observing the changes in spot size. The executive-sensor method is only suitable for the double deck or biplate cantilever. The impedance analysis method can measure cantilevers with any size and structure, but it only can measure the frequecy modal of the piezoelectric cantilever. Eddy current displacement meter can measure the real magnitude of mechanical vibration directly, but it can only suitable for the large beam. LDV is mature, which can measure the cantilever with smaller size. The optical measurement method is directviewing, and it can measure smaller size, but the experimental conditions is not easily achieved.
Keywords/Search Tags:Piezoelectric Microcantilever, Dynamics Characterization Testing, LabVIEW
PDF Full Text Request
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