liu.seSearch for publications in DiVA
Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • oxford
  • 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
Attenuation of Harmonic Distortion in Loudspeakers Using Non-linear Control
Linköping University, Department of Electrical Engineering, Automatic Control. Linköping University, The Institute of Technology.
Linköping University, Department of Electrical Engineering, Automatic Control. Linköping University, The Institute of Technology.
2012 (English)Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesisAlternative title
Olinjär reglering för dämpning av harmonisk distorsion i högtalare (Swedish)
Abstract [en]

The first loudspeaker was invented almost 150 years ago and even though much has changed regarding the manufacturing, the main idea is still the same. To produce clean sound, modern loudspeaker consist of expensive materials that often need advanced manufacturing equipment. The relatively newly established company Actiwave AB uses digital signal processing to enhance the audio for loudspeakers with poor acoustic properties. Their algorithms concentrate on attenuating the linear distortion but there is no compensation for the loudspeakers' non-linear distortion, such as harmonic distortion.

To attenuate the harmonic distortion, this thesis presents controllers based on exact input-output linearisation. This type of controller needs an accurate model of the system. A loudspeaker model has been derived based on the LR-2 model, an extension of the more common Thiele-Small model.

A controller based on exact input-output linearisation also needs full state feedback, but since feedback risk being expensive, state estimators were used. The state estimators were based on feed-forward or observers using the extended Kalman filter or the unscented Kalman filter. A combination of feed-forward state estimation and a PID controller were designed as well.

In simulations, the total harmonic distortion was attenuated for all controllers up to 180 Hz. The simulations also showed that the controllers are sensitive to inaccurate parameter values in the loudspeaker model. During real-life experiments, the controllers needed to be extended with a model of the used amplifier to function properly. The controllers that were able to attenuate the harmonic distortion were the two methods using feed-forward state estimation. Both controllers showed improvement compared to the uncontrolled case for frequencies up to 40 Hz.

Place, publisher, year, edition, pages
2012. , 69 p.
Keyword [en]
EKF, exact linearisation, feed-forward, loudspeaker modelling, non-linear control, UKF
National Category
Control Engineering
Identifiers
URN: urn:nbn:se:liu:diva-78645ISRN: LiTH-ISY-EX--12/4579--SEOAI: oai:DiVA.org:liu-78645DiVA: diva2:534340
External cooperation
Actiwave AB
Subject / course
Automatic Control
Uppsok
Technology
Supervisors
Examiners
Available from: 2012-06-18 Created: 2012-06-16 Last updated: 2012-06-18Bibliographically approved

Open Access in DiVA

fulltext(950 kB)820 downloads
File information
File name FULLTEXT01.pdfFile size 950 kBChecksum SHA-512
e8ac356a31a8cb9fa85549e4be21f7dd70c55973739e2fc8473f60168bef455d7031944263ac8ad529995518686a9764f6056dfacfc8cf2fd51b82f9ac4ef8c3
Type fulltextMimetype application/pdf

Search in DiVA

By author/editor
Arvidsson, MarcusKarlsson, Daniel
By organisation
Automatic ControlThe Institute of Technology
Control Engineering

Search outside of DiVA

GoogleGoogle Scholar
Total: 820 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

urn-nbn

Altmetric score

urn-nbn
Total: 1221 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • oxford
  • 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