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Full-Text Articles in Engineering

Minimax Registration For Point Cloud Alignment, Zhaohui Geng, Mauro Garcia, Bopaya Bidanda Sep 2022

Minimax Registration For Point Cloud Alignment, Zhaohui Geng, Mauro Garcia, Bopaya Bidanda

Manufacturing & Industrial Engineering Faculty Publications and Presentations

The alignment, or rigid registration, of three-dimensional (3D) point clouds plays an important role in many applications, such as robotics and computer vision. Recently, with the improvement in high precision and automated 3D scanners, the registration algorithm has become critical in a manufacturing setting for tolerance analysis, quality inspection, or reverse engineering purposes. Most of the currently developed registration algorithms focus on aligning the point clouds by minimizing the average squared deviations. However, in manufacturing practices, especially those involving the assembly of multiple parts, an envelope principle is widely used, which is based on minimax criteria. Our present work …


Holographically Recorded Photopolymer Diffractive Optical Element For Holographic And Electronic Speckle Pattern Interferometry, Sridhar Guntaka, Vincent Toal, Suzanne Martin Jan 2002

Holographically Recorded Photopolymer Diffractive Optical Element For Holographic And Electronic Speckle Pattern Interferometry, Sridhar Guntaka, Vincent Toal, Suzanne Martin

Articles

A diffractive optical element is described that can be used to implement a self-aligning electronic speckle apttern interferometer and holographic interferometer requiring only a laser source and a camera in the optical set-up.


Prediction Of Soakout Time Using Analytical Models, B. Chakravarthy, H. P. Cherukuri, R. G. Wilhelm Jan 2002

Prediction Of Soakout Time Using Analytical Models, B. Chakravarthy, H. P. Cherukuri, R. G. Wilhelm

Department of Mechanical and Materials Engineering: Faculty Publications

In precision manufacturing enterprises, machine parts at nonstandard temperatures are often soaked to standard temperature prior to making any dimensional measurements. The soakout times are usually determined using lumped heat-transfer models where the part temperatures are assumed to be uniform. This article discusses conditions under which lumped model assumptions are valid by comparing lumped analyses for various shapes and materials with the more general finite element results. In addition, the effect of ambient temperature cycling on part response is also studied.


Task Specific Uncertainty In Coordinate Measurement, R. G. Wilhelm, R. Hocken, H. Schwenke Jan 2001

Task Specific Uncertainty In Coordinate Measurement, R. G. Wilhelm, R. Hocken, H. Schwenke

Department of Mechanical and Materials Engineering: Faculty Publications

Task specific uncertainty is the measurement uncertainty associated with the measurement of a specific feature using a specific measurement plan. This paper surveys techniques developed to model and estimate task specific uncertainty for coordinate measuring systems, primarily coordinate measuring machines using contacting probes. Sources of uncertainty are also reviewed.


Part Form Errors Predicted From Machine Tool Performance Measurements, R. G. Wilhelm, N. Srinivasan, F. Farabaugh, R. Hocken Jan 1997

Part Form Errors Predicted From Machine Tool Performance Measurements, R. G. Wilhelm, N. Srinivasan, F. Farabaugh, R. Hocken

Department of Mechanical and Materials Engineering: Faculty Publications

Machine tool performance testing, as defined by IS0 230 and ANSI B5.54 has been successfully used to maintain and improve the accuracy and repeatability of production-level machine tools. In this study, a controlled series of experiments have been used to test the efficacy of these performance tests in the prediction of part form errors. Results are shown for flatness, squareness, position, and profile tolerances. The experimental results suggest that standard machine tool performance tests can also be used to predict the “best-case” tolerances that can be achieved for particular part features.