Stochastic relative degree and path-wise control of nonlinear stochastic systems
Author(s)
Mellone, A
Scarciotti, Giordano
Type
Journal Article
Abstract
We address the path-wise control of systems described by a set of nonlinear stochastic differential equations. For this class of systems, we introduce a notion of stochastic relative degree and a change of coordinates which transforms the dynamics to a stochastic normal form. The normal form is instrumental for the design of a state-feedback control which linearises and makes the dynamics deterministic. We observe that this control is idealistic, i.e. it is not practically implementable because it employs a feedback of the Brownian motion (which is never available) to cancel the noise. Using the idealistic control as a starting point, we introduce a hybrid control architecture which achieves practical path-wise control. This hybrid controller uses measurements of the state to perform periodic compensations for the noise contribution to the dynamics. We prove that the hybrid controller retrieves the idealistic performances in the limit as the compensating period approaches zero. We address the problem of asymptotic output tracking, solving it in the idealistic and in the practical framework. We finally validate the theory by means of a numerical example.
Date Issued
2023-04-01
Date Acceptance
2022-05-02
Citation
IEEE Transactions on Automatic Control, 2023, 68 (4), pp.1970-1985
ISSN
0018-9286
Publisher
Institute of Electrical and Electronics Engineers
Start Page
1970
End Page
1985
Journal / Book Title
IEEE Transactions on Automatic Control
Volume
68
Issue
4
Copyright Statement
© The Author(s) 2022. Available open access under a Creative Commons Attribution License 4.0 International (https://creativecommons.org/licenses/by/4.0/)
License URL
Publication Status
Published
Date Publish Online
2022-05-10