Localization For Automated Inspection Of Curved Surfaces
- Authors
- Leonidas Bardis (Department of Naval Architecture and Marine Engineering, National Technical University of Athens) | Richard A. Jinkerson (U.S. Navy, Supervisor of Shipbuilding, Conversion and Repair) | Nicholas M. Patrikalakis (Department of Ocean Engineering, Design Laboratory, Massachusetts Institute of Technology Cambridge)
- Document ID
- ISOPE-91-01-3-228
- Publisher
- International Society of Offshore and Polar Engineers
- Source
- International Journal of Offshore and Polar Engineering
- Volume
- 1
- Issue
- 03
- Publication Date
- September 1991
- Document Type
- Journal Paper
- Language
- English
- ISSN
- 1053-5381
- Copyright
- 1991. The International Society of Offshore and Polar Engineers
- Keywords
- CAE, inspection, CAD, automation, curved surface
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ABSTRACT :
This paper deals with localization of curved surfaces, meaning the optimum positioning of a target surface obtained by some manufacturing process with respect to an ideal design surface. The localization problem is formulated as an optimum parameter estimation problem involving rigid body translations and rotations obtained through unconstrained minimization of a distance norm. An iterative localization algorithm has been developed that terminates when the magnitudes of rigid body translations and rotations become smaller than preset threshold values. To reduce the cost of localization for large amounts of data arising in high-precision applications involving free-form surfaces, methods to improve the efficiency of the process based on coherence considerations of the input data are investigated. An example based on actual measured data from a manufactured sculptured surface illustrates our technique.
INTRODUCTION
Localization is the process of verification of shape conformance of a manufactured part with a toleranced geometric description of an object. For objects with very high precision requirements, the need exists for accurate localization methods, due to the inaccuracies of physical manufacturing processes. The specific problem addressed is localization of a target surface with respect to an ideal design surface. The target surface may be represented by either a parametric surface predicted from numerical simulation of a manufacturing process, or by directly measured data from a manufactured surface. The design surface is a rational B-spline surface patch. Applications similar to these arise frequently in marine, aerospace and mechanical engineering problems. For solution of the problem with high precision addressed in this paper, knowledge of the manufactured surface using parametric equations, or a dense set of measured data points, is needed. In Wierzbicki (1990), methods are suggested to simulate the shape of a thin plate subjected to die-less forming operations using analytic and numerical techniques.
This paper deals with localization of curved surfaces, meaning the optimum positioning of a target surface obtained by some manufacturing process with respect to an ideal design surface. The localization problem is formulated as an optimum parameter estimation problem involving rigid body translations and rotations obtained through unconstrained minimization of a distance norm. An iterative localization algorithm has been developed that terminates when the magnitudes of rigid body translations and rotations become smaller than preset threshold values. To reduce the cost of localization for large amounts of data arising in high-precision applications involving free-form surfaces, methods to improve the efficiency of the process based on coherence considerations of the input data are investigated. An example based on actual measured data from a manufactured sculptured surface illustrates our technique.
INTRODUCTION
Localization is the process of verification of shape conformance of a manufactured part with a toleranced geometric description of an object. For objects with very high precision requirements, the need exists for accurate localization methods, due to the inaccuracies of physical manufacturing processes. The specific problem addressed is localization of a target surface with respect to an ideal design surface. The target surface may be represented by either a parametric surface predicted from numerical simulation of a manufacturing process, or by directly measured data from a manufactured surface. The design surface is a rational B-spline surface patch. Applications similar to these arise frequently in marine, aerospace and mechanical engineering problems. For solution of the problem with high precision addressed in this paper, knowledge of the manufactured surface using parametric equations, or a dense set of measured data points, is needed. In Wierzbicki (1990), methods are suggested to simulate the shape of a thin plate subjected to die-less forming operations using analytic and numerical techniques.
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