Research On Preloading Device Of Piezoelectric Force Measuring Unit

With the development of technology and modern manufacturing,it is very important for the measurement and analysis of force.It is necessary to measure and monitor the change of force at any time.Piezoelectric sensors can play a good role in static and dynamic measurement,and it is of great significance to carry out research on the measurement accuracy of the load cell.In this paper,the following research work is carried out with the goal of controlling and improving the test accuracy of the piezoelectric force measuring unit:The advantages of the force measuring unit compared with the traditional crystal box force measurement are analyzed.For the accuracy loss during the assembly of the force measuring unit,the force sharing theory is used to quantify the error,which provides a theory for the subsequent accuracy improvement method and the corresponding structure development.support.The design and selection of the assembled fixture of the load cell were carried out.According to the assembled requirements of the load cell,the corresponding structure was designed in that reduce the installation angle between the upper and lower covers of the load cell as much as possible during the assembly of the load cel,and the static and modal simulation analysis was performed using ANSYS Workbench,which has decided the final structure.Through the empirical formula,the preload values required for the two types of force measurement units are calculated,and the preload assembly experiments are performed on the two types of units with the designed fixture.The angle test is performed on the assembled force measuring unit,and the angular deflection between the upper and lower covers of the force measuring unit and the crystal box is measured by an inverse trigonometric function.The calibration error caused by the eccentric loading of the traditional calibration device to the test results are analyzed,and two sets of semi-open calibration devices according to the requirements are designed.According to the test results obtained by the static calibration experiment,the main and lateral sensitivities,nonlinear errors,repeatability,and various phase-to-phase interferences are calculated.After carrying out the preload test,deflection angle test and static&dynamic calibration experiment on ten sets of force measuring units,it is concluded that the assembled angle deflection of the force measuring unit can be controlled within 1 ° through the assembled fixture.Linearity and repeatability are controlled within 1%.The lateral cross-talk can becontrolled within 3%,and the main phase cross-talk can be controlled within 1%.The test accuracy in the assembed process of the load cell has been greatly improved.