Design Of Signal Processing Unit And Data Management System For Roundness Instrument

The roundness error of cycloid workpiece affects the quality of the machine which uses it, so it is of great significance to assure the quality of product by measuring correctly the roundness error of workpiece. Compared with various measuring methods of roundness error, the best choice is the roundness instrument measuring method for its high-precision characteristics. Based on the analysis and measuring of Talycenta51 Roundness Instrument and the software platform LabVIEW, the thesis provides an innovatory scheme for the software and hardware. Under the condition of keeping the machinery part, the scheme improves signal conditioning circuits, puts the measuring signal into the computer by data acquisition, processes data by LabVIEW and reports the measurement result in graphical. This thesis takes the following works:The basic model of the roundness error measurement is introduced, and various measurements and their corresponding error evaluation methods are balanced. This thesis indicates that the measurement method of roundness instrument is the most optimal method, so it is essential and meaningful to rebuild Talycenta Roundness Instrument.On the principle of roundness tester, the thesis introduces the hardware of roundness structure on detail, designs the overall rebuilding program, analyzes the sensor processing circuit and method to make it come true, discusses why and how to level and center the worktable, and completes the data acquisition of circle signal.According to the demand of instrument, a brief description of the software model is given and the data management system is designed to analyze data and control motor. The thesis finishes the programming of data acquisition. In terms of GB/T7235-2004, the IIR digital filter is designed and its edge effect also under control. Finally, the evaluation-algorithm of roundness error is interpreted and programmed.On the requirement of measurement system, the parameters of the sensor calibration must be given by experiments. The repeatability and validity of the measurement instruments is also testified. The reasons of error are analyzed and the measures to improve the instrument precision are given on the base of the analysis of the experimental result.