@inproceedings{1e1e2035131644d29627bb1dfabbb275,
title = "System identification and signal processing for PID control of B0 shim systems in ultra-high field magnetic resonance applications",
abstract = "Magnetic resonance (MR) scanners are important tools in medical diagnostics and in many areas of neuroscience. MR technology is moving towards ultra-high field (UHF) 7T and 9.4T scanners which provide more signal intensity. However they also suffer from inhomogeneity of the static (B0) magnetic field which can lead to artifacts and uninterpretable data. B0 shimming is a technique used to reduce inhomogeneities but most MR scanners use static shim settings for the duration of the experiment. Dynamic shim updating (DSU) updates the shim in real-time while the scan is in process and can hence reduce any fluctuations in B0 field which may arise due to patient breathing, mechanical vibrations and soforth. However DSU is currently very slow and if we intend to increase the update rate then control theory needs to be applied. This paper presents an application of basic system identification and signal processing in the context of MR systems for DSU. Although system identification of these systems has been done before, they are non-parametric frequency domain approaches. These systems can be modelled as linear multivariable systems.",
keywords = "Gyromagnetic ratios, Hurwitz criterion, Medical systems, PID controllers, Parameter optimization, Phase-locked loop, Process identification, Smoothing filters",
author = "Chang, {Yu Chun} and Nikolai Avdievich and Anke Henning",
note = "Publisher Copyright: {\textcopyright} IFAC.; 19th IFAC World Congress on International Federation of Automatic Control, IFAC 2014 ; Conference date: 24-08-2014 Through 29-08-2014",
year = "2014",
doi = "10.3182/20140824-6-za-1003.01828",
language = "English (US)",
series = "IFAC Proceedings Volumes (IFAC-PapersOnline)",
publisher = "IFAC Secretariat",
pages = "7517--7522",
editor = "Edward Boje and Xiaohua Xia",
booktitle = "19th IFAC World Congress IFAC 2014, Proceedings",
address = "Austria",
}