Ringwood, John
(2002)
Diagonalisation of a class of
multivariable system via an actuator
linearisation technique.
Information Sciences, 148 (1-4).
pp. 139-154.
ISSN 0020-0255
Abstract
Many multivariable (systems with many inputs/outputs) industrial processes can, to a
good degree of approximation, be modelled by a transfer function matrix, where all of
the interaction occurs in a matrix of constant coefficients. This reflects the fact that the
dynamics of the section in which the interaction occurs are very fast compared with the
other dynamics in the system. Examples of such systems include steel rolling mills and
boiler systems.
Such multivariable systems are relatively easy to design controllers for, since the
system may be diagonalised by an inverse of the constant gain matrix, followed by
suitable single-loop dynamic compensation. However, this approach depends on the
linearity of the dynamical elements in the system. Such a condition is voilated by
the presence of non-linear actuators, which are a feature of many industrial systems. The
presence of such actuators within a multivariable control system as described above can
cause very significant interaction problems, with associated degradation in performance,
particularly during transients.
This paper describes a straightforward technique, which is effective in linearising
typical non-linear industrial actuators, allowing diagonalisation to be effectively
achieved at all frequencies. The technique relies on a simple describing function analysis
and manifests itself as a time-varying linearising precompensator for each non-linear
actuator. A simple example is used to demonstrate the effectiveness of the method and it
is then shown in application with multivariable boiler and steel mill models.
| Item Type: |
Article
|
| Keywords: |
Automation; Multivariable systems; Actuator linearisation; Steel mills; Boiler control; |
| Academic Unit: |
Faculty of Science and Engineering > Electronic Engineering |
| Item ID: |
6915 |
| Depositing User: |
Professor John Ringwood
|
| Date Deposited: |
21 Jan 2016 15:11 |
| Journal or Publication Title: |
Information Sciences |
| Publisher: |
Elsevier |
| Refereed: |
Yes |
| URI: |
|
| Use Licence: |
This item is available under a Creative Commons Attribution Non Commercial Share Alike Licence (CC BY-NC-SA). Details of this licence are available
here |
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