Automatic Precision Measurement Of Micro-displacement For Piezoelectric Ceramic Slices

Piezoelectric ceramic(PZT)material which have the advantages of high resolution,fast response speed,and large driving force are widely used in the field of sensors and actuators due to their good piezoelectric and converse piezoelectric effect.As the core driving part of the laser gyroscope frequency stabilizer,the dual piezoelectric ceramic slices can adjust the resonator cavity length of the gyroscope bi-directionally to achieve the purpose of stabilizing the gyroscope working frequency.This requires that the paired piezoelectric ceramic slices have the same properties which means the micro-displacements of piezoelectric ceramic slices are close to each under the equal driving voltage.Therefore,it is necessary to measure the microdisplacement of the piezoelectric ceramic slices and match them according the measuring results before the assembly of the laser gyro frequency stabilizer.Aiming at the problem of measurement,the article analyzed the displacement characteristics of piezoelectric ceramics,designed a measurement method based on dual inductance micrometer,explored the driving voltage loading strategy,developed a micro-displacement automatic measurement equipment for piezoelectric ceramic slices,and the performance and measuring accuracy of the equipment were analyzed experimentally in the end.Firstly,the upper and lower electrode structures which can load the driving voltage and compact the ceramic slices was designed,based on the analysis of the displacement principle of piezoelectric ceramic material.By comparing the single-probe and dual-probe measuring method and experimental verification,a relative measuring method based on dual inductance micrometers was determined.A driving voltage loading scheme that can meet the measuring efficiency and ensure the measurement accuracy was determined through experiments.Then,the micro-displacement automatic measurement equipment for piezoelectric ceramic slices was developed,the measuring equipment was divided into loading and blanking module,measuring module and carrying module.The loading module completed the alignment of the ceramic slices before loading to ensure that the ceramic slices can be accurately picked up during automatic measurement.The blanking module was used to classify and store the ceramic slices after the measurement.The carrying module used a pair of orthogonal linear guide rails to realize the transportation of piezoelectric ceramic slices cooperating with the photoelectric sensors.The picking of the ceramic slices was completed by vacuum adsorption to avoid accidental damage during mechanical clamping.In the measurement module,the upper and lower electrodes pressed the ceramic slices and loaded voltage to them.Two high-precision inductive micrometers completed the micro-displacement measurement of piezoelectric ceramic slices.In order to achieve uniform contact between the ceramic slices and the electrodes and ensure the effect of voltage loading,the upper electrode used the combination structure of ball bearing and elastic probe.According to the automatic measuring process,the design pattern and control strategy of the automatic software were determined,including the system initialization strategy,measurement strategy,ceramic slices picking and remaining quantity detection strategy and etc.The control program for the equipment were written based on LabVIEW,which realized the function of automatic measurement and debugging,and a friendly human-computer interaction interface was designed.Finally,the performance indicators of the equipment were tested,including the repeatable positioning accuracy of the motion guide and the output performance of the piezoelectric controller.Automatic measurement of the micro-displacement for large number of piezoelectric ceramic slices was completed by the equipment,and the error analysis was performed.Compared to manual measurement,the measuring efficiency is improved by at least 60%.Through the comparison of multiple measurement experiments,the measurement results of the automatic measurement equipment and the laser interferometer had high consistency.By analyzing the multiple measuring results of single ceramic slice,it showed that the repeatability accuracy of the equipment was better than 0.06 ?m.