Research On Automatic Calibration System For Digital Display Vibrometers

In this thesis, the key technologies and system integration of an automatic calibration system of digital display vibrometers for Zhejiang Electric Power Test Research Institute had been studied.In chapter 1, the destination and significance of the thesis were presented. First, the digital display vibrometer and its traditional calibration process were introduced. Then, the present research status of automatic measurement and control system for vibration calibration was surveyed and its developing trend was pointed out. In succession, the present research status both at home and abroad of the recognition algorithms for display value of meters was surveyed and the key technologies of the algorithms were analyzed. At last, the main research aim and content of the thesis were emphasized.In chapter 2, the overall structure of the automatic calibration system for digital display vibrometers was proposed. First, the principle and components of the system were introduced. Then, the key instruments in the system were selected. At last, the system bus design was analyzed.In chapter 3, the automatic recognition algorithms for the display value of meters were proposed. First, the image acquisition process was introduced. Then, the algorithms of image grayscale, filter, morphological process, binarization, stroke correct, segmentation and number confirmation were introduced successively. At last, the influence of image vibration on recognition precision and the recognition of digits in transition were analyzed.In chapter 4, the software of the automatic calibration system designed for digital display vibrometers was present. At the beginning, the requirements of the software were analyzed. And then the overall framework of the software was put forward. In the end, the software was introduced, which was developed with graphical programming language-LabVIEW.In chapter 5, the experiments for the designed automatic calibration system were done. The precision of the vibration level adjustment, the recognition precision of the meters' display value and the implementation status of the software were mainly tested. Experimental results show that the automatic calibration system could meet the design requirements.In chapter 6, the achievements of the thesis were briefly summarized and the further research work was expected.