Research On The Roundness Tester Intelligent Transformation

The roundness tester is a high precision instrument that is widely used to measure therotary workpiece in mechanical industry. Talyrond 73 roundness tester is the object of thisstudy. Its precision spindle, other mechanical structure and LVDT(Linear Variable Different-ial Transformer) still have met the work requirement. but electronic units exceed the life ofservice, they are at a high failure rate of service, and they are no longer the value of mainte-nance. In the seventies and eighties of the last century, Related companies of China haveimported a large number of precision roundness tester. Problems of these roundness testers arein a similar with tester of my research.Therefore, it is important to transform the traditionalroundness testers.On the basis of looking up and deep studies of relative literature data home and abroad,this paper studies the working principle of the roundness tester, analyses the existenceproblems of the Talyrond 73 roundness tester before the transformation, due to the technicalcondition limit, data logging and error evaluation methods are a waste of time and energy.And measurement results are affected by human factors. So measurement accuracy is notguaranteed. And this paper makes feasible transformation scheme: At the precondition ofretaining the mechanical structure of instrument, this paper improve the circuit of signalprocessor by modeling, And the computer is used to acquire data by the special data acqu-irement card based on the PCI bus card inserting form.The data Processing includes four kinds of roundness evaluating method, such as LeastSquares Mean Circle (LSC), Minimum Zone Circles (MZC), Minimum Circumscribed Circle(MCC), Maximum Insceibed Circle (MIC). And the four kinds of algorithm of roundnessevaluating method is derived in detail.The evaluation of roundness error is interpreted and programmed.With the platform ofVirtual Instrument development software (LabVIEW), the evaluation software of roundness error developed in this thesis is actualized on the platform of LabVIEW, and the evaluation ofroundness error can be achieved. In terms of the national standard (GB/T7235-2004), The IIRdigital filter is designed and its edge effect is controlled within reasonable limits.The eval-uation result of roundness error outputs to a graphical. In comparision with traditional mea-suring and data processing method, This instrument is not only intelligence of data loggingand storage in the testing process, but also automation, intelligence of roundness error eval-uation. At the same time, it greatly increases the testing and data processing speed.