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International Standard Serial Number:
ISSN 1001-4551
Sponsor:
Zhejiang University;
Zhejiang Machinery and Electrical Group
Edited by:
Editorial of Journal of Mechanical & Electrical Engineering
Chief Editor:
ZHAO Qun
Vice Chief Editor:
TANG ren-zhong,
LUO Xiang-yang
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Abstract: Aiming at the problem of selecting sampling points when evaluating the calculation size of cylinder,a calculation size of roundness profiles was studied based on broken lines and arcs. A method based on broken lines and arcs to characterize the contour of a circle was proposed, its perimeter and area evaluation models were established, and the influence of the number of sampling points on the calculated size of the cylinder was analyzed. Firstly, the extraction of cylinder contour elements was explained, the systematic error of their radial sizes of the cylinder was determined, and a calculation method of perimeter, area and volume of roundness profiles was proposed based on broken lines and arcs, the corresponding evaluation models for perimeter diameters, area diameters and volume diameters of roundness profiles were established. Then, for the different sampling points of each roundness profile, the theoretical calculation of the differences between the calculation values of perimeters of the broken-line (arcs) based profiles and the perimeters of the corresponding circles or ellipses and between the calculation values of areas of the broken-line (arcs) based profiles and the areas of the corresponding circles or ellipses were carried out. Finally, the roundness profiles of sample were extracted based on seven different sampling points, the perimeter diameters, area diameters and volume diameters of the sample were evaluated on the basis of the established models of calculation sizes. According to the theoretical calculations and experiments, the influence of the number of sampling points on the cylindrical calculation sizes was researched. The research results show that when the roundness profiles are characterized by the broken-lines, the number of the sampling points has larger influence on the evaluation results of perimeter diameters and volume diameters and has relative less influence on the evaluation results of area diameters, and that when the roundness profiles are characterized by the arcs, the number of the sampling points has very small influence on the evaluation results of perimeter diameters, area diameters and volume diameters.
Key words: calculation size evaluation model; perimeter diameter; area diameter; volume diameter; profile extraction; roundness profiles characterized by broken-lines(arcs)