Research On Multidimensional Force Measurement Technology Of Large Span Piezoelectric Dynamometer

Large-size and heavy-load equipment needs to be tested for its performance before it is officially used.The force state is one of the parameters that directly reflect the performance of the equipment,and the realization of its high-precision test is of great significance to the research and development of large-scale equipment.The test system based on the piezoelectric principle is widely used in the field of force testing due to its advantages of high rigidity,high natural frequency,high linearity and so on.At present,the piezoelectric dynamometers widely used and studied are all small in span,and there is a lack of research on large-span dynamometers suitable for large-scale equipment.This paper takes mechanical analysis and experiment as the research method,and takes the long-span piezoelectric dynamometer as the research object,and conducts research with the purpose of realizing the accurate measurement of the force amplitude and the point of action.It aims to lay the foundation for the design,manufacture,and decoupling methods of large-span piezoelectric dynamometers.This paper mainly completed the following work:Based on the characteristics of the confirmatory experiment,combined with the existing equipment in the laboratory,with strength and rigidity as the requirements,the structural design of the dynamometer is completed.The finite element software is used to analyze the possible influence of the large-span dynamometer with dimensional error and stiffness difference.Completed the design of installation and loading structure.The performance test of the piezoelectric force measuring unit and the force measuring instrument has been completed.The piezoelectric force measuring unit is calibrated in three directions and the height is measured,and the piezoelectric force gauge is calibrated in the center position of the three directions.Aiming at the phenomenon that the output of the piezoelectric force measuring unit is different,the reasons for the output difference are analyzed through a variety of methods,and the influence of the output difference on the force gauge and the reduction method are studied.The experiment of the variable loading point of the dynamometer in the direction of the main force has been completed,and the error analysis and compensation have been carried out.The load experiment is carried out on the load point of the dynamometer in the direction of the main force.In view of the error in the measurement of the loading point in the experiment,a mechanical model of the dynamometer under weak rigidity was established.Based on the mechanical model,a method for solving the position of the loading point with the joint fitting of high-order functions was proposed,which improved the loading point position solution accuracy.Aiming at the phenomenon of error in force amplitude measurement in the experiment,the reason for this phenomenon is analyzed based on finite element simulation and a compensation method is proposed.The load experiment of variable loading point is carried out on the dynamometer in the lateral force direction,and the data is analyzed and processed by the same method as the main force experiment.