Fixtureless inspection of deformable parts using partial captures

Jaramillo, A.; Prieto, Flavio; Boulanger, Pierre

doi:10.1007/s12541-013-0012-3

Cited by 12 publications

(13 citation statements)

References 19 publications

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“…Typically, these methods try to find a nonrigid registration that minimizes the Euclidian distance between the acquisition data (or SCAN) and the nominal CAD while respecting some criteria related to the intrinsic (dimensional & shape) properties of the part. The nonrigid point set registration performed within a flexible registration method can be based on a Finite Element Analysis (FEA) [3][4][5][6][7][8][9][10][11][12][13][14] or based on a probability density estimation [16][17]. As a result, a flexible registration operation is either FEA-based or probabilistic.…”

Section: ) Flexible Registration (With Complementary Defect Identifimentioning

confidence: 99%

The fixtureless inspection of flexible parts based on semi-geodesic distance

Babanezhad

Foucault

Sabri

et al. 2019

Precision Engineering

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Some types of manufactured parts like sheet metals and skins often have a significantly different shape in a free-state position compared to their state-of-use position (as defined by their nominal CAD models) due to a combination of gravity and/or the residual effects of stress. Traditionally known as flexible (nonrigid compliant) parts, these dedicated fixtures are used for inspection operations in order to maintain flexible parts from a free-state position to a state-of-use position. This paper introduces a new automatic defect identification method primarily intended for two less-investigated manufacturing defect types: contour profile errors and hole localization. By combining simple techniques such as mesh boundary detection, fast boundary-based correspondence searches and accurate fast marching on triangulated meshes, the semi-geodesic distances from each boundary vertex on the acquired SCAN mesh to all the other boundary vertices is calculated, stored in a table and then compared to the corresponding values on the part's nominal CAD mesh. The comparisons found in the tables result in an estimation of the location and amplitude of the two aforementioned defect types. Compared to other work in this field, the overall approach does not rely on any mesh registration or finite-element analysis with tedious boundary conditions setup. It is also relatively fast. A fast algorithm/app based on this method was named the AFDA (Automatic Free-state Defect Approximation) and was validated against case studies in the aerospace sector. The results reflect the utility and effectiveness of the proposed approach.

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Section: ) Flexible Registration (With Complementary Defect Identifimentioning

confidence: 99%

The fixtureless inspection of flexible parts based on semi-geodesic distance

Babanezhad

Foucault

Sabri

et al. 2019

Precision Engineering

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“…The challenge to overcome by these methods is to compensate for the shape changes of the nonrigid part when it is not fixed to its design shape. The aforementioned simulated displacements methods [6][7][8][9][10][11][12][13][14][15][16] rely on a numerical approach to virtually compare the shape of the measured part in free-state and its nominal CAD model. The comparison is done by imposing displacements on either the part's free-state or its nominal CAD to force it into taking the shape of the other.…”

Section: Fixtureless Inspectionmentioning

confidence: 99%

Aerospace Panels Fixtureless Inspection Methods with Restraining Force Requirements; A Technology Review

Abenhaim

Tahan

Desrochers

et al. 2013

SAE Technical Paper Series

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Aerospace panels are commonly restrained on complex inspection fixture jigs during the measurement process. Forces used to restrain the parts are also monitored as mandated by thier functional requirements. Given the difficulties in measuring these types of parts, this paper reviews the available fixtureless inspection methods with a focus on the challenges of their implementation, and their aptitude to be used to estimate the profile and the necessary restraining forces of an aerospace panel. To perform this investigation, finite element analysis is used to predict the constrained shape of four (4) simulated free-state aerospace panels, with two different type of boundary conditions, in five scenarios. From those analyses, the importance and limits of current finite element boundary setting methods embedded in fixtureless inspection methods for nonrigid parts are highlighted.

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“…The raw output provided by these scanners is a 3D point cloud, from which a triangulated mesh can easily be obtained. Beholden to progress about CAD and CAI methods, fixtureless non-rigid inspection methods [3][4][5][6][7][8][9][10][11][12] are developed. These methods consist in virtually compensating for the compliance of non-rigid parts.…”

Section: Introductionmentioning

confidence: 99%

“…However, generating FE meshes for each measured part and locating appropriate BCs for each scan model hinder automating the inspection process of these CAI methods. Therefore, non-rigid inspection methods based on applying FEA on CAD models instead of scan models have been introduced in [6][7][8][9][10][11][12]. Indeed, these non-rigid inspection methods generally use meshes with better quality since these meshes are generated from CAD models.…”

Section: Introductionmentioning

confidence: 99%

Assessment of the Robustness of a Fixtureless Inspection Method for Nonrigid Parts Based on a Verification and Validation Approach

Karganroudi

Cuillière

Vincent

et al. 2017

Journal of Verification, Validation and Uncertainty Quantification

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The increasing practical use of computer-aided inspection (CAI) methods requires assessment of their robustness in different contexts. This can be done by quantitatively comparing estimated CAI results with actual measurements. The objective is comparing the magnitude and dimensions of defects as estimated by CAI with those of the nominal defects. This assessment is referred to as setting up a validation metric. In this work, a new validation metric is proposed in the case of a fixtureless inspection method for nonrigid parts. It is based on using a nonparametric statistical hypothesis test, namely the Kolmogorov–Smirnov (K–S) test. This metric is applied to an automatic fixtureless CAI method for nonrigid parts developed by our team. This fixtureless CAI method is based on calculating and filtering sample points that are used in a finite element nonrigid registration (FENR). Robustness of our CAI method is validated for the assessment of maximum amplitude, area, and distance distribution of defects. Typical parts from the aerospace industry are used for this validation and various levels of synthetic measurement noise are added to the scanned point cloud of these parts to assess the effect of noise on inspection results.

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Fixtureless inspection of deformable parts using partial captures

Cited by 12 publications

References 19 publications

The fixtureless inspection of flexible parts based on semi-geodesic distance

The fixtureless inspection of flexible parts based on semi-geodesic distance

Aerospace Panels Fixtureless Inspection Methods with Restraining Force Requirements; A Technology Review

Assessment of the Robustness of a Fixtureless Inspection Method for Nonrigid Parts Based on a Verification and Validation Approach

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