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Search Publications by: Vincent Lee (Fed)

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Displaying 1 - 25 of 40

Redetermination of the Gravitational Constant using the BIPM Torsion Balance

July 8, 2024
Author(s)
Stephan Schlamminger, Leon Chao, David B. Newell, Vincent Lee, Clive Speake
For the past several years, we have been using the torsion balance developed at the Bureau International des Poids et Mesures (BIPM) to measure the gravitational constant $G$. The most notable feature of the apparatus is that it allows the measurement of

Laser tracker interim testing per the ASME B89.4.19-2021 and ISO 10360-10:2021 standards

June 28, 2023
Author(s)
Marcos Motta de Souza, Bala Muralikrishnan, Vincent Lee, Daniel S. Sawyer
The recently revised ASME B89.4.19-2021 and ISO 10360-10:2021 standards for laser trackers include a new interim test that is comprehensive and more sensitive to systematic errors than the interim tests in the previous versions of the standards, i.e., the

Determination of the Gravitational Constant Using a BIPM Balance

December 12, 2022
Author(s)
Stephan Schlamminger, Leon Chao, Vincent Lee, David B. Newell, Clive Speake
With the torsion balance developed at the Bureau International des Poids et Mesures (BIPM), the Newtonian constant of gravitation, $G$, can be measured with two methods. In the Cavendish method, the external gravitational torque is obtained from the

DIMENSIONAL METROLOGY IN DETERMINATION OF G WITH BIPM'S TORSION BALANCE

November 7, 2022
Author(s)
Vincent Lee, Stephan Schlamminger, Leon Chao, David B. Newell, Jon Pratt, Craig Shakarji, Clive Speake
This paper discusses the dimensional metrology challenges encountered while performing G measurements using the BIPM torsion balance and our solutions.

Precision Engineering For Gravitational Experiments

October 10, 2022
Author(s)
Stephan Schlamminger, Leon Chao, Vincent Lee, David B. Newell, Jon Pratt, Clive Speake
Four fundamental forces, or technically more correct interactions, are known in physics. The gravitational force is one of them and is a mysterious one. Gravity has an infinite range, just like the electromagnetic interaction. However, in contrast to

Design of an electrostatic feedback for an experiment to measure G

June 20, 2022
Author(s)
Stephan Schlamminger, Leon Chao, Vincent Lee, David B. Newell, Clive Speake
The torsion pendulum at the heart of the BIPM apparatus to measure the gravitational constant, $G$, is used to measure the gravitational torque between source and test-mass assemblies with two methods. In the Cavendish method, the pendulum moves freely. In

The Crane Operator's Tricks and other Shenanigans with a Pendulum

February 18, 2022
Author(s)
Stephan Schlamminger, Leon Chao, David B. Newell, Vincent Lee
The dynamics of a swinging payload suspended from a stationary crane can be described as a simple pendulum, typically an unwelcome phenomenon on a construction site. An experienced crane operator can deliver a swinging payload and stop dead on target in a

Improvised Long Test Lengths via Stitching Scale Bar Method: Performance Evaluation of Terrestrial Laser Scanners per ASTM E3125-17

May 28, 2020
Author(s)
Shendong Shi, Balasubramanian Muralikrishnan, Vincent Lee, Daniel S. Sawyer, Octavio Icasio-Hern?ndez
Periodic performance evaluation is a critical issue for ensuring the reliability of data from terrestrial laser scanners (TLSs). With the recent introduction of the ASTM E3125-17 standard, there now exist standardized test procedures for this purpose

Methods to improve the dimensional measurement accuracy of a motion tracking system

April 1, 2020
Author(s)
Shendong Shi, Balasubramanian Muralikrishnan, Vincent D. Lee, Daniel S. Sawyer
Photogrammetry based motion tracking systems are widely used in entertainment, medicine, sports, and other industries for low accuracy positioning applications. Camera-based systems track cooperative markers on objects to obtain their real-time positions

A First realization of ASTM E3125-17 test procedures for laser scanner performance evaluation

February 1, 2020
Author(s)
Ling Wang, Balasubramanian Muralikrishnan, Vincent D. Lee, Prem K. Rachakonda, Daniel S. Sawyer, Joe Gleason
Spherical coordinate three-dimensional (3D) imaging systems, such as Terrestrial Laser Scanners (TLS), are already used widely in different fields. Their measurement performance evaluation is a topic of active research. In 2017, the first comprehensive

Methods to calibrate a three-sphere scale bar for laser scanner performance evaluation per the ASTM E3125-17

February 1, 2020
Author(s)
Ling Wang, Balasubramanian Muralikrishnan, Vincent D. Lee, Prem K. Rachakonda, Daniel S. Sawyer, Joe Gleason
A scale bar with sphere targets is one way of realizing the symmetric and asymmetric length tests to evaluate terrestrial laser scanner (TLS) performance per the ASTM E3125-17 standard. The length of the scale bar is required to be known with an expanded

X-ray computed tomography instrument performance evaluation: Detecting geometry errors using a calibrated artifact

April 30, 2019
Author(s)
Balasubramanian Muralikrishnan, Katharine M. Shilling, Steven D. Phillips, Wei Ren, Vincent D. Lee, Felix H. Kim, Gabriel Alberts, Valentina Aloisi
X-ray computed tomography (XCT) is uniquely suitable for non-destructive dimensional metrology of delicate or internal features generated from the additive manufacturing process. While XCT has long been used in medical imaging, it has only been used for

Concept to Commercialization of an Artifact for Evaluating 3D Imaging Systems per the ASTM E3125- 17

June 29, 2018
Author(s)
Balasubramanian Muralikrishnan, Prem K. Rachakonda, Vincent D. Lee, Katharine M. Shilling, Daniel S. Sawyer, Geraldine S. Cheok, Luc Cournoyer, Joe Gleason
The newly released ASTM E3125-17 standard describes several point-to-point distance tests to evaluate the performance of spherical coordinate 3D imaging systems, commonly referred to as terrestrial laser scanners (TLS). The relative-range error test, which

Challenges in measuring spherical geometry using terrestrial laser scanners

November 1, 2017
Author(s)
Balasubramanian Muralikrishnan, Prem K. Rachakonda, Katharine M. Shilling, Vincent D. Lee, Daniel S. Sawyer, Geraldine S. Cheok, Luc Cournoyer
Terrestrial laser scanners (TLS) measure 3D coordinates in a scene by recording the range, the azimuth angle, and elevation angle of discrete points on target surfaces. They are increasingly used in a variety of applications, including manufacturing and

Methods and Considerations to Determine Sphere Center from Terrestrial Laser Scanner Point Cloud Data

September 6, 2017
Author(s)
Prem K. Rachakonda, Balasubramanian Muralikrishnan, Luc Cournoyer, Geraldine S. Cheok, Vincent D. Lee, Katharine M. Shilling, Daniel S. Sawyer
The Dimensional Metrology Group (DMG) at the National Institute of Standards and Technology (NIST) is performing research to support the development of documentary standards within ASTM E57 committee. This committee is addressing the point-to-point

Relative range error evaluation of terrestrial laser scanners using a plate, a sphere, and a novel dual-sphere-plate target

July 21, 2017
Author(s)
Balasubramanian Muralikrishnan, Prem K. Rachakonda, Vincent D. Lee, Katharine M. Shilling, Daniel S. Sawyer, Geraldine S. Cheok
Terrestrial laser scanners (TLS) are a class of 3D imaging systems that produce a 3D point cloud by measuring the range and two angles at different sampling locations. The ranging unit of a TLS realizes the SI unit of length. Relative range error is one

Targets for Relative Range Error Measurement of 3D Imaging Systems

May 1, 2017
Author(s)
Prem K. Rachakonda, Balasubramanian Muralikrishnan, Katharine M. Shilling, Geraldine S. Cheok, Vincent D. Lee, Christopher J. Blackburn, Dennis S. Everett, Daniel S. Sawyer
The Dimensional Metrology Group (DMG) at the National Institute of Standards and Technology (NIST) is performing research to support the development of documentary standards within ASTM E57 for the point-to-point performance evaluation of 3D imaging

Report on the May 2016 ASTM E57.02 instrument runoff at NIST, Part 1 – Background information and key findings

October 19, 2016
Author(s)
Balasubramanian Muralikrishnan, Prem K. Rachakonda, Katharine M. Shilling, Vincent D. Lee, Christopher J. Blackburn, Daniel S. Sawyer, Geraldine S. Cheok, Luc Cournoyer
There is ongoing activity within ASTM E57.02 working group WK43218 [1] to develop a documentary standard for point-to-point distance performance evaluation of 3D imaging systems. The Dimensional Metrology Group (DMG) at the National Institute of Standards