Geometric control and disturbance decoupling for fractional systems

We develop a geometric approach for fractional linear time-invariant systems with Caputo-type derivatives. In particular, we generalize the fundamental notions of invariance and controlled invariance to the fractional setting. We then exploit this new geometric framework to address the disturbance d...

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Main Authors: Padula, Fabrizio, Ntogramatzidis, Lorenzo, Schmid, R., Loxton, Ryan
Format: Journal Article
Language:English
Published: SIAM PUBLICATIONS 2020
Subjects:
Online Access:http://hdl.handle.net/20.500.11937/89487
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author Padula, Fabrizio
Ntogramatzidis, Lorenzo
Schmid, R.
Loxton, Ryan
author_facet Padula, Fabrizio
Ntogramatzidis, Lorenzo
Schmid, R.
Loxton, Ryan
author_sort Padula, Fabrizio
building Curtin Institutional Repository
collection Online Access
description We develop a geometric approach for fractional linear time-invariant systems with Caputo-type derivatives. In particular, we generalize the fundamental notions of invariance and controlled invariance to the fractional setting. We then exploit this new geometric framework to address the disturbance decoupling problem via static pseudostate feedback, with and without stability. Our main contribution is a set of necessary and sufficient conditions for the disturbance decoupling problem that are related to the input-output properties of the closed-loop system, and hence they are applicable not just to Caputo-type derivatives but, more broadly, to any type of fractional system. These results show that, while the conditions for guaranteeing the existence of a decoupling pseudostate feedback remain essentially unchanged, the underlying theoretical framework is substantially different, because the fractional derivative is a nonlocal operator and this property plays a major role in the characterization of the evolution of the pseudostate trajectory. In particular, we show that, unlike the integer case, the infinite-dimensional nature of fractional systems means that feedback control is insufficient to maintain the pseudostate trajectory on a controlled invariant subspace, unless the entire past history of the pseudostate has evolved on that subspace. However, feedforward control can achieve this task under certain necessary and sufficient geometric conditions.
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spelling curtin-20.500.11937-894872023-06-13T05:54:10Z Geometric control and disturbance decoupling for fractional systems Padula, Fabrizio Ntogramatzidis, Lorenzo Schmid, R. Loxton, Ryan Science & Technology Technology Physical Sciences Automation & Control Systems Mathematics, Applied Mathematics controlled invariance disturbance decoupling fractional systems CONTROLLABILITY OBSERVABILITY ASSIGNMENT TRANSIENTS We develop a geometric approach for fractional linear time-invariant systems with Caputo-type derivatives. In particular, we generalize the fundamental notions of invariance and controlled invariance to the fractional setting. We then exploit this new geometric framework to address the disturbance decoupling problem via static pseudostate feedback, with and without stability. Our main contribution is a set of necessary and sufficient conditions for the disturbance decoupling problem that are related to the input-output properties of the closed-loop system, and hence they are applicable not just to Caputo-type derivatives but, more broadly, to any type of fractional system. These results show that, while the conditions for guaranteeing the existence of a decoupling pseudostate feedback remain essentially unchanged, the underlying theoretical framework is substantially different, because the fractional derivative is a nonlocal operator and this property plays a major role in the characterization of the evolution of the pseudostate trajectory. In particular, we show that, unlike the integer case, the infinite-dimensional nature of fractional systems means that feedback control is insufficient to maintain the pseudostate trajectory on a controlled invariant subspace, unless the entire past history of the pseudostate has evolved on that subspace. However, feedforward control can achieve this task under certain necessary and sufficient geometric conditions. 2020 Journal Article http://hdl.handle.net/20.500.11937/89487 10.1137/19M1261493 English SIAM PUBLICATIONS fulltext
spellingShingle Science & Technology
Technology
Physical Sciences
Automation & Control Systems
Mathematics, Applied
Mathematics
controlled invariance
disturbance decoupling
fractional systems
CONTROLLABILITY
OBSERVABILITY
ASSIGNMENT
TRANSIENTS
Padula, Fabrizio
Ntogramatzidis, Lorenzo
Schmid, R.
Loxton, Ryan
Geometric control and disturbance decoupling for fractional systems
title Geometric control and disturbance decoupling for fractional systems
title_full Geometric control and disturbance decoupling for fractional systems
title_fullStr Geometric control and disturbance decoupling for fractional systems
title_full_unstemmed Geometric control and disturbance decoupling for fractional systems
title_short Geometric control and disturbance decoupling for fractional systems
title_sort geometric control and disturbance decoupling for fractional systems
topic Science & Technology
Technology
Physical Sciences
Automation & Control Systems
Mathematics, Applied
Mathematics
controlled invariance
disturbance decoupling
fractional systems
CONTROLLABILITY
OBSERVABILITY
ASSIGNMENT
TRANSIENTS
url http://hdl.handle.net/20.500.11937/89487