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Mertl Jiří and Čech Martin and Schlegel Miloš : One point relay identification experiment based on constant-phase filter . Process Control 2008, vol. ;, p. 1-9, University of Pardubice, Kouty nad Desnou, 2008.


Using standard relay identification methods, one obtains a critical frequency response point with the phase shift -180 degrees. Such phase is not optimal for consequential PI(D) controller design especially when there is no additional knowledge about the process (e.g. static gain). Currently, an adaptive filter is used to get a frequency response sample with different phase shift. Adaptive filter parameters are tuned during the identification experiment. Unfortunately, the adaptation makes the experiment more time consuming. This paper presents a new low-order filter providing arbitrary constant phase at about three decades. Such filter embedded into relay tuner shortens the experiment significantly. Further, the paper discusses several implementation aspect. The authors believe that presented approach may lead to improvement of existing relay autotuners

Detail of publication

Title: One point relay identification experiment based on constant-phase filter
Author: Mertl Jiří ; Čech Martin ; Schlegel Miloš
Language: English
Year: 2008
Type of publication: Papers in proceedings of reviewed conferences
Title of journal or book: Process Control 2008
Číslo vydání: ;
Page: 1 - 9
ISBN: 978-80-7395-077-4
Publisher: University of Pardubice
Address: Kouty nad Desnou
Date: 12 Jun 2008
2011-03-15 16:21:32 / 2011-03-15 16:21:32 / 1


relay identification experiment, constant phase filter, fractional-order integrator


 author = {Mertl Ji\v{r}\'{i} and \v{C}ech Martin and Schlegel Milo\v{s}},
 title = {One point relay identification experiment based on constant-phase filter},
 year = {2008},
 publisher = {University of Pardubice},
 journal = {Process Control 2008},
 address = {Kouty nad Desnou},
 volume = {;},
 pages = {1-9},
 ISBN = {978-80-7395-077-4},
 url = {},