An intelligent sampling method for inspecting free-form surfaces

Obeidat, Suleiman; Raman, S. Ganesh Sundara

doi:10.1007/s00170-008-1427-3

Cited by 94 publications

(39 citation statements)

References 18 publications

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“…3 can be applied conveniently. The surface is more suitable for an algorithm involving patch-size ranking as suggested by Obeidat and Raman [9]. One can easily visualize the nature of the example surface using contour plots given in Fig.…”

Section: Resultsmentioning

confidence: 99%

“…The patch size ranking strategy proposed by Obeidat and Raman [9] is suitably modified to work for a given sample size. The knot vectors (U, V) are used to divide the given design surface into patches and the patch sizes are computed.…”

Section: Distribution Based On Patch Sizementioning

confidence: 99%

“…Obeidat and Raman [9] proposed three heuristic algorithms for sampling of freeform surface patches using maximum Gaussian curvature, mean Gaussian curvatures and the point with average of the mean Gaussian curvature and minimum Gaussian curvature as critical points. The first algorithm starts with three sample locations in each patch corresponding to the critical points and places additional sample points in low density patches.…”

Section: Introductionmentioning

confidence: 99%

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Practical Measurement Strategies for Verification of Freeform Surfaces Using Coordinate Measuring Machines

Rajamohan¹,

Shunmugam

Samuel

2011

Metrology and Measurement Systems

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Freeform surfaces have wider engineering applications. Designers use B-splines, Non-Uniform Rational Bsplines, etc. to represent the freeform surfaces in CAD, while the manufacturers employ machines with controllers based on approximating functions or splines. Different errors also creep in during machining operations. Therefore the manufactured freeform surfaces have to be verified for conformance to design specification. Different points on the surface are probed using a coordinate measuring machine and substitute geometry of surface established from the measured points is compared with the design surface. The sampling points are distributed according to different strategies. In the present work, two new strategies of distributing the points on the basis of uniform surface area and dominant points are proposed, considering the geometrical nature of the surfaces. Metrological aspects such as probe contact and margins to be provided along the sides have also been included. The results are discussed in terms of deviation between measured points and substitute surface as well as between design and substitute surfaces, and compared with those obtained with the methods reported in the literature.

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Section: Resultsmentioning

confidence: 99%

Section: Distribution Based On Patch Sizementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Practical Measurement Strategies for Verification of Freeform Surfaces Using Coordinate Measuring Machines

Rajamohan¹,

Shunmugam

Samuel

2011

Metrology and Measurement Systems

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“…the geometrical accuracy of a used coordinate measuring machine and the accuracy of the algorithms included in the metrological software which cooperates with coordinate measuring systems. The measurement software of measuring systems may include, for example, the various methods of probe radius correction process used in order to calculate the coordinates of corrected measured points [2,3], the different algorithms of the distribution of points [4][5][6] or the various methods of the best fit of measured data to nominal one [7].…”

Section: Introductionmentioning

confidence: 99%

The Calculation of the Nominal Data of a Turbine Blade with the Use of CAD Software

Magdziak

2015

MATEC Web of Conferences

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Abstract. In the article there was presented the comparison of the nominal data of a selected turbine blade which were calculated by using of both the measurement software Blade Pro -cooperating with, for example, coordinate measuring machines -and the computer aided design software CATIA. The comparison of the nominal data of the chosen workpiece was conducted in order to perform the analysis of the possibility of using the software CATIA in the case of the measurement application which is usually conducted by means of the coordinate measuring technique. The nominal data in the case of the two analyzed software packages concern the selected measurement characteristics of a turbine blade. The correct calculations of the nominal data have direct influence on the results of the real coordinate measurements of a turbine blade.

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“…In designing, producing and measuring such surfaces, CAD/CAM techniques are applied. The accuracy inspection consists in digitalizing the workpiece under research, followed by comparing the obtained coordinates of the measurement points with the CAD design (model) [1,2]. There are generally two types of measurement data acquisition methods: contact measurement using a coordinate measuring machine (CMM) and non-contact measurement by using an optical/laser scanner.…”

Section: Introductionmentioning

confidence: 99%

Fitting Spatial Models of Geometric Deviations of Free-Form Surfaces Determined in Coordinate Measurements

Poniatowska

Werner

2010

Metrology and Measurement Systems

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Local geometric deviations of free-form surfaces are determined as normal deviations of measurement points from the nominal surface. Different sources of errors in the manufacturing process result in deviations of different character, deterministic and random. The different nature of geometric deviations may be the basis for decomposing the random and deterministic components in order to compute deterministic geometric deviations and further to introduce corrections to the processing program. Local geometric deviations constitute a spatial process. The article suggests applying the methods of spatial statistics to research on geometric deviations of free-form surfaces in order to test the existence of spatial autocorrelation. Identifying spatial correlation of measurement data proves the existence of a systematic, repetitive processing error. In such a case, the spatial modelling methods may be applied to fitting a surface regression model representing the deterministic deviations. The first step in model diagnosing is to examine the model residuals for the probability distribution and then the existence of spatial autocorrelation.

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An intelligent sampling method for inspecting free-form surfaces

Cited by 94 publications

References 18 publications

Practical Measurement Strategies for Verification of Freeform Surfaces Using Coordinate Measuring Machines

Practical Measurement Strategies for Verification of Freeform Surfaces Using Coordinate Measuring Machines

The Calculation of the Nominal Data of a Turbine Blade with the Use of CAD Software

Fitting Spatial Models of Geometric Deviations of Free-Form Surfaces Determined in Coordinate Measurements

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