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A HEURISTIC APPROACH TO INSPECTION OF SCULPTURED SURFACES USING DATA LOCALIZATION

JOSHI, MANDAR
http://rave.ohiolink.edu/etdc/view?acc_num=ucin1183076418

Abstract Details

2007, MS, University of Cincinnati, Engineering : Mechanical Engineering.
Automatic inspection of the manufactured parts is an important area related to Computer Aided Inspection. Since any manufacturing process induces some errors either due to chance causes of variation or assignable causes of variation, it is necessary to inspect the manufactured part or surface to check if it is within the design tolerance limits or not. For a sculptured surface there is no clear way to measure the characteristic dimensions (such as the length or diameter for cylinder) on the manufactured part. Hence, to determine if the manufactured surface is within the specification limits, it is necessary to compare the measurement data directly with the CAD model of the surface. The CAD model exists in the Design Coordinate System (DCS) while the measurement data exists in Machine Coordinate System (MCS) attached to the inspection system. In order to compare the measurement data with CAD model, it is necessary to align the two coordinate systems together.Data Localization is the process of determining the transformation parameters to align the measured data points with the CAD model. This can be formulated as a non linear optimization problem in six variables. The traditional Iterative Closest Point (ICP) algorithm involves computation of closest point on the design surface for a given measurement point and can be formulated as an optimization problem in ‘u’ and ‘v’ (parameters defining the free form surface). This problem can be solved using Newton’s method which requires a very good initial guess to ensure the convergence to the solution. The new heuristic algorithm developed in this research mainly focuses on efficient pre-processing of the design and measurement datasets by arranging them very close to each other. Such pre-processing gives a very good initial estimate of the corresponding closest point. Hierarchical data structure namely k-d tree is then used to arrive at a good estimate for the final Newton’s method. The new heuristic was implemented for inspecting different free form surfaces and the results were compared.
Dr. Sam Anand (Advisor)
92 p.
Automated Inspection; Data Localization; Sculptured Surfaces

Recommended Citations

Citations

  • JOSHI, M. (2007). A HEURISTIC APPROACH TO INSPECTION OF SCULPTURED SURFACES USING DATA LOCALIZATION [Master's thesis, University of Cincinnati]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1183076418

    APA Style (7th edition)

  • JOSHI, MANDAR. A HEURISTIC APPROACH TO INSPECTION OF SCULPTURED SURFACES USING DATA LOCALIZATION. 2007. University of Cincinnati, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=ucin1183076418.

    MLA Style (8th edition)

  • JOSHI, MANDAR. "A HEURISTIC APPROACH TO INSPECTION OF SCULPTURED SURFACES USING DATA LOCALIZATION." Master's thesis, University of Cincinnati, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1183076418

    Chicago Manual of Style (17th edition)

ucin1183076418
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© 2007, all rights reserved.
This open access ETD is published by University of Cincinnati and OhioLINK.