Jody Muelaner

A wide range of metrology processes are involved in the manufacture of large products. In addition to the traditional tool setting and product verification operations increasingly flexible metrology enabled automation is also being used. Faced with many possible measurement problems and a very large number of metrology instruments, employing diverse technologies, the selection of the appropriate instrument for a given task can be highly complex. Also, since metrology has become a key manufacturing process it should be considered in the early stages of design, and there is currently very little research to support this. This paper provides an overview of the important selection criteria for typical measurement processes and presents some novel selection strategies. Metrics which can be used to assess measurability are also discussed. A prototype instrument selection and measurability analysis application is also presented with discussion of how this can be used as the basis for development of a more sophisticated measurement planning tool.

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Authors

J E Muelaner, B Cai, P G Maropoulos

Department of Mechanical Engineering, The University of Bath, Bath, UK

Published in

IMechE, Part B: J. Engineering Manufacture, 2010.

Volume and page number information

Volume 224, Number 6
Pages 853-868

Metrology processes used in the manufacture of large products include tool setting, product verification and flexible metrology enabled automation. The range of applications and instruments available makes the selection of the appropriate instrument for a given task highly complex. Since metrology is a key manufacturing process it should be considered in the early stages of design. This paper provides an overview of the important selection criteria for typical measurement processes and presents some novel selection strategies. Metrics which can be used to assess measurability are also discussed. A prototype instrument selection and measurability analysis application is presented with discussion of how this can be used as the basis for development of a more sophisticated measurement planning tool.

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Authors

J E Muelaner, B Cai, P G Maropoulos

Department of Mechanical Engineering, The University of Bath, Bath, UK

Published in

6th International Conference on Digital Enterprise Technology. 2009: Hong Kong

Volume and page number information

This report presents the results of testing of the Metris iGPS system performed by the National Physical Laboratory (NPL) and the University of Bath (UoB), with the assistance of Metris, and Airbus at Airbus, Broughton in March 2008. The aim of the test was to determine the performance capability of the iGPS coordinate metrology system by comparison with a reference measurement system based on multilateration implemented using laser trackers. A network of reference points was created using SMR nests fixed to the ground and above ground level on various stands. The reference points were spread out within the measurement volume of approximately 10 m × 10 m × 2 m. The coordinates of each reference point were determined by the laser tracker survey using multilateration. The expanded uncertainty (k=2) in the relative position of these reference coordinates was estimated to be of the order of 10 μm in x, y and z. A comparison between the iGPS system and the reference system showed that for the test setup, the iGPS system was able to determine lengths up to 12 m with an uncertainty of 170 μm (k=2) and coordinates with an uncertainty of 120 μm in x and y and 190 μm in z (k=2).

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Notes

These tests were carried out using a state of the art iGPS system,
which was operated and continually monitored by a team of engineers from the
system manufacturer (Metris). This network consisted of 8 transmitters and
12 monument sensors. The full use of all transmitters and monuments therefore
required over 100 lines of sight to be simultaneously maintained while
measurements were being taken.

Authors

Ben Hughes, Alistair Forbes, Wenjuan Sun

The National Physical Laboratory

P G Maropoulos, J E Muelaner, J Jamshidi, Z Wang

The University of Bath

Published by

Queen’s Copyright Printer and Controller of HMSO

ISSN

ISSN 1754-2987

The paper presents a review of the principles and state of the art in instrumentation used to make large scale measurements within aerospace assembly. The ability to measure large artefacts accurately is a key enabling technology to improve quality and facilitate automation. Particular emphasis is placed on issues of uncertainty with the importance of acceptance criteria explained and verification standards compared and discussed. The fundamental technologies deployed are explained including laser trackers, indoor GPS and photogrammetry. Commercially available systems are compared in terms of uncertainty, range and deployment related issues.

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Authors

J.E. Muelaner, P.G. Maropoulos

Department of Mechanical Engineering, University of Bath, Bath, UK

Presented at

5th International Conference on Digital Enterprise Technology

22-24 October 2008, Nantes, France

The indoor Global Positioning System (iGPS) is an innovative measurement system consisting of a network of Rotary-laser automatic theodolites (R-LATs) which provide a factory wide coordinate measurement system. The primary benefits of the system are that a theoretically unlimited number of sensors are able to simulatiously detect position using signals from a common network of transmitters and that the sensors are able to automatically regain connection to the network following a disruption of the line of sight. The basic functionality of this system is described together with a brief overview of work to verify its performance.

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Authors

J E Muelaner, Z Wang, J Jamshidi, P G Maropoulos, A R Mileham

Department of Mechanical Engineering, The University of Bath, Bath, UK

Presented at

3rd International Conference on Manufacturing Engineering.

2008: Kassandra-Chalkidiki, Greece.

Volume and page number information

p. 805-810