Research On Parameter Optimization Design Of Weight Volume Measuring Device Based On Acoustic Volume Method

Air buoyancy correction is necessary for the high accuracy mass measurement of weights.In which the volume of the weight is an important parameter of air buoyancy correction calculations.The accuracy of volume measurement is affected by the driving signal parameters of the volume measurement device and the position of vessel rotation.The acoustic finite element simulation of the coupled vessel and experimental verification are used to select the optimal driving signal parameters and improve the measurement method.Thus the relative extended uncertainty of 100 g to 50 g weight volume measurement is less than 6×10^-4.The relative extension uncertainty of 20 g to 1 g weights meets the requirements of the extended uncertainty of E₁ grade weights.The specific contents of this research are as follows:?1?The system structure and measurement model of volume measuring device by acoustic method are analyzed in detail.The double reference weight method with higher measurement accuracy was selected as the guidance method for simulation and experiment.According to the system structure,measurement model and measurement method of the device,the key parameters affecting the acoustic volume measurement are analyzed.?2?The coupling vessel of the device is selected as the research object to establish the model.The Virtual.Lab software is used to conduct finite element simulation analysis of the coupled vessel.The optimal drive signal parameters for weights volume measurement are obtained by simulation.?3?The volume measurement device of acoustic method is set up and the acoustic acquisition software parameters were configured to match the software and hardware.At the same time,the hydrostatic method is used to measure the actual volume values of the standard weights and the test weights which could be used to analyze and verify the simulation results and the accuracy of the acoustic volume measurement.?4?The results of acoustic finite element simulation are verified by a volume measurement experiment.The influence of vessel rotation position change on the measurement of weight volume was studied by analyzing the difference between the acoustic simulation results and the actual acoustic measurement results.After optimizing the structure and measurement method of the device,the error and uncertainty of the measurement result of the weight volume are evaluated.