| The piezoelectric ceramic is widely used in precision system as actuator owing to its advantages,including fast response,great force output,wide frequency range,high accuracy and compactness etc.It has been a hot development of new drive material.The piezoelectric ceramics are used in pairs in ring laser gyroscopes.However,the piezoelectric ceramic is sometimes broken by its pair because the slight difference of force outputs between them.In addition,the different force outputs of the same pair of piezoelectric ceramics may affect the service life and stability of ring laser gyroscopes.Which lead to certain losses in economy In order to match the different piezoelectric ceramics optimally,it is significant to measure the force output of the piezoelectric ceramic precisely.Combined with the Dielectric properties of piezoelectric ceramics,a rigid body electrode plate model is constructed on the basis of the displacement output characteristics of piezoelectric ceramics In this paper,.A mathematic model of the force output of piezoelectric ceramics is established and analyzed.The output of piezoelectric ceramic mainly depends on the polarization strength,excitation voltage and stiffness of piezoelectric ceramics.In addition,the output is also affected by its shape and frequency of operation.In this paper,the original method of measuring the force output of piezoelectric ceramic is analyzed.The original measurement method is insufficient,for example,the cumbersome testing process,easy to introduce errors,easy to damage piezoelectric ceramic in Testing process and so on In terms of these drawbacks,a new test method is proposed.Compared to the original test method,Force applying system and displacement control system are added.In the process of testing the elongated measured element applied a voltage is pressed back to its original length by force applying device,the amount of compression is precisely controlled by displacement measuring system.During the whole process,the force outputs of the piezoelectric ceramics at different displacement outputs are recorded.The new test method can test piezoelectric ceramics of various shapes,The measurement procedure is simple and the test result is accurate.In this paper,a test system is set up based on the new test method proposed.This system mainly consists of a flexible hinge structure based on piezoelectric actuator,a pair of support structures,piezoelectric actuator,capacitance micrometer,force sensor,industrial computer and corresponding hardware circuit.According to the requirement of accuracy,the physical structures is strictly discussed and the effects of the lean of piezo-slices on the device are also theoretically analyzed.The functional requirements of software system are analyzed and the host computer program is designed based on Labview,The main functions of it are as follows,displacement control of micro-motion stage,data collection and storage of the force output of piezoelectric ceramics The performance of the device is tested? The motion resolution of device could be 0.03?m and 0.01 N,respectively.and the maximum force capacity of the device could reach up to 76.4 N.And a series of experiments are carried to test the relationships of force output and displacement of piezoelectric stacks and the rectangle of piezoelectric ceramic slices.Meanwhile,the curves of voltage and the maximum force output are presented.And the uncertainty and error analysis are presented,too.The experimental results indicate that the force outputs can be measured though the proposed instrument precisely.Compared with the traditional method,the new instrument can measure the maximum force output directly and obtain the curves of force output –displacement and force output-voltage.The experimental results show that the proposed instrument to test the force output of piezoelectric ceramic has a reasonable structure,a novel working principle and high precision.It is reliable and can be achieved force output tests of piezoelectric ceramics. |
PDF Full Text Request