Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Automatic detection of material phase transitions from spectroscopic data
University West, Department of Engineering Science, Division of Automation and Computer Engineering. (PTW)ORCID iD: 0000-0002-2824-0271
University West, Department of Engineering Science, Division of Automation and Computer Engineering. (PTW)ORCID iD: 0000-0001-5608-8636
2013 (English)In: Proceedings of the IECON 2013: 39th Annual Conference of the IEEE Industrial Electronics Society, IEEE, 2013, p. 2384-2389Conference paper, Published paper (Refereed)
Abstract [en]

When using a temperaturemeasurementmethod which utilizes spectral information for measuring the temperature of varying emissivity measurands, there is a need for a temperature reference at some point in time. In this work, such a reference is created from the spectral radiance data already used by the temperature measurement method. A method of using knowledge of the measurand material's phase transitions and spectral radiance data as a temperature reference is presented. Through automatical identification of phase transitions from radiance spectra employing signal processing, the temperature is known at a certain instance in time, just like required by the temperature measurement method. Three methods for automatic identification of material phase transitions from spectroscopic data are examined and evaluated. The methods are, based on derivatives, steady-state identification and cross correlation respectively. They are introduced and evaluated using experimental data collected from a solidifying copper sample. All methods proved to identify the phase transitions correctly. The addition of automatic phase transition identification supplements the existing temperature measurement method such that it becomes a stand alone, reference free method for measuring the true absolute temperature of a measurand with varying emissivity.

Place, publisher, year, edition, pages
IEEE, 2013. p. 2384-2389
Series
Proceedings of the Annual Conference of the IEEE Industrial Electronics Society, ISSN 1553-572X
Keywords [en]
materialphase transitions, spectroscopic data, WIL, Work-integrated Learning
Keywords [sv]
AIL
National Category
Robotics
Research subject
ENGINEERING, Manufacturing and materials engineering; Work Integrated Learning
Identifiers
URN: urn:nbn:se:hv:diva-5609DOI: 10.1109/IECON.2013.6699504Scopus ID: 2-s2.0-84893523136ISBN: 978-1-4799-0223-1 (print)OAI: oai:DiVA.org:hv-5609DiVA, id: diva2:649437
Conference
IECON 2013. 39th Annual Conference of the IEEE Induistrial Electronics Society. In conjunction with ICELIE 2013, IWIES 2013. Vienna, Austria 10-13 November 2013
Note

 Article number 6699504

Available from: 2013-09-18 Created: 2013-09-18 Last updated: 2018-08-09Bibliographically approved
In thesis
1. Instrumentation and estimation for high temperature control
Open this publication in new window or tab >>Instrumentation and estimation for high temperature control
2013 (English)Licentiate thesis, comprehensive summary (Other academic)
Abstract [en]

Within a variety of industrially relevant high temperature production processes such as welding, heat treatment and metal deposition, the quality of the manufactured component is largely affected by how well parameters can be controlled during processing. These parameters might be, in the case of metal deposition, power input, material feed, or a parameter which is common for all of the aforementioned processes: material temperature. The ability to correctly measure, or in other ways estimate process parameters is vital in order to successfully control high temperature processes such as above 700 degrees Celsius. In this work, instrumentation and estimation solutions adapted to high temperature control are proposed and implemented with a focus on the laser metal wire deposition process. Special attention is given to temperature measurements on specimens with varying emissivity as commonly found in high temperature processes. A calibration procedure for a single-wavelength pyrometer is also presented together with a general discussion on limitations of such a system for measurands with varying emissivity. A new method for non-contact emissivity compensated temperature estimations using a spectrometer is presented. Simulations and industrially relevant experiments have been carried out validating the method. The theoretical framework for the developed method will be further investigated in the future together with additional experimental validation. In addition to temperature measurements, a method for real-time process control of laser metal wire deposition has been developed and implemented with good results. This control scheme estimates and controls the tool-to-workpiece distance based on resistance measurements. Such measurements allow for placement of instruments outside of the processing chamber and easy integration into existing equipment. Future work will be directed towards incorporation of resistance measurements into an iterative learning control scheme. Also, improvement on the resistance-distance model and further investigation into suitable signal processing methods for the resistance signal will be pursued.

Place, publisher, year, edition, pages
Göteborg: Chalmers Reproservice, 2013. p. 156
Series
R - Department of Signals and Systems, Chalmers University of Technology, ISSN 1403-266x ; R017
Keywords
Additive Manufacturing, Automation, Emissivity, Emissivity Compensated Spectral Pyrometry, Laser Metal Wire Deposition, Metal Deposition, Pyrometry, Resistance Feedback Control, Thermometry, Varying Emissivity
National Category
Robotics
Research subject
ENGINEERING, Manufacturing and materials engineering; ENGINEERING, Physics
Identifiers
urn:nbn:se:hv:diva-5602 (URN)
Presentation
2013-09-25, C118, Högskolan Väst, Trollhättan, 09:25 (English)
Opponent
Supervisors
Funder
EU, FP7, Seventh Framework Programme, 266271
Available from: 2013-09-25 Created: 2013-09-18 Last updated: 2016-02-08Bibliographically approved
2. Non-intrusive instrumentation and estimation: Applications for control of an additive manufacturing process
Open this publication in new window or tab >>Non-intrusive instrumentation and estimation: Applications for control of an additive manufacturing process
2015 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

For integration of additive manufacturing into industrial production, there is a need for capable yet robust automation solutions. Such solutions are to ensure consistent process outputs, both with regard to deposit geometry and material properties. In this thesis, instrumentation and control solutions have been investigated for the laser metal wire deposition additive manufacturing process. This particular process is promising with regard to e.g. high deposition rates and negligible material waste. However, due to its inherent dynamics, it requires automatic control in order to prove competitive. A large number of process parameters affect the resulting quality of the deposit. Successful control of these parameters is crucial for turning laser metal wire deposition into an industrially tractable process. This requires relevant and reliable process information such as the temperature of the deposit and the positioning of the tool relative to the workpiece. Due to the particular requirements of instrumenting the process, only non-intrusive measurement methods are viable. In this thesis, such measurement solutions are presented that advance automatic control of the laser metal wire deposition. In response to the need for accurate temperature measurements for the process, a new temperature measurement method has been developed. By adopting the novel concept of temporal, rather than spectral, constraints for solving the multispectral pyrometry problem, it opens up for temperature measurements which compensates for e.g. an oxidising deposit. For maintaining a good deposition process in laser metal wire deposition, control of tool position and wire feed rate is required. Based on measurements of resistance through the weld pool, a simple yet well performing control system is presented in this thesis. The control system obtains geometrical input information from resistance measurements made in-situ, and feeds this information to an iterative learning controller. This results in a robust, cheap and practical control solution for laser metal wire deposition, which is suitable for industrial use and that can easily be retrofitted to existing equipment.

Place, publisher, year, edition, pages
Göteborg: Chalmers University of Technology,, 2015. p. 98
Series
Doktorsavhandlingar vid Chalmers tekniska högskola. Ny serie, ISSN 0346-718X ; 3829
Keywords
Additive Manufacturing, Automation, Emissivity, Emissivity Compensated Spectral Pyrometry, Laser Metal Wire Deposition, Metal Deposition, Pyrometry, Resistance Feedback Control, Thermometry
National Category
Manufacturing, Surface and Joining Technology
Research subject
ENGINEERING, Manufacturing and materials engineering
Identifiers
urn:nbn:se:hv:diva-7428 (URN)9789175971483 (ISBN)
Opponent
Supervisors
Available from: 2015-03-06 Created: 2015-03-06 Last updated: 2016-02-08Bibliographically approved

Open Access in DiVA

No full text in DiVA

Other links

Publisher's full textScopus

Authority records BETA

Hagqvist, PetterChristiansson, Anna-Karin

Search in DiVA

By author/editor
Hagqvist, PetterChristiansson, Anna-Karin
By organisation
Division of Automation and Computer Engineering
Robotics

Search outside of DiVA

GoogleGoogle Scholar

doi
isbn
urn-nbn

Altmetric score

doi
isbn
urn-nbn
Total: 199 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf