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Publications (10 of 21) Show all publications
Guay, M. & Atta, K. (2019). A set-based model-free reinforcement learning design technique for nonlinear systems. International Journal of Adaptive Control and Signal Processing, 33(2), 315-334
Open this publication in new window or tab >>A set-based model-free reinforcement learning design technique for nonlinear systems
2019 (English)In: International Journal of Adaptive Control and Signal Processing, ISSN 1099-1115, Vol. 33, no 2, p. 315-334Article in journal (Refereed) Published
Abstract [en]

Summary In this study, we propose an extremum-seeking approach for the approximation of optimal control problems for a class of unknown nonlinear dynamical systems. The technique combines a phasor extremum-seeking controller with a reinforcement learning strategy. The learning approach is used to estimate the value function of an optimal control problem of interest. The phasor extremum-seeking controller implements the approximate optimal controller. The approach is shown to provide reasonable approximations of optimal control problems without the need for a parameterization of the nonlinear system’s dynamics. A simulation example is provided to demonstrate the effectiveness of the technique.

Place, publisher, year, edition, pages
John Wiley & Sons, 2019
Keywords
extremum-seeking control, phasor approximation, reinforcement learning
National Category
Control Engineering
Research subject
Control Engineering
Identifiers
urn:nbn:se:ltu:diva-71744 (URN)10.1002/acs.2949 (DOI)000458861100006 ()2-s2.0-85058854004 (Scopus ID)
Note

Validerad;2019;Nivå 2;2019-02-06 (johcin)

Available from: 2018-11-28 Created: 2018-11-28 Last updated: 2019-03-14Bibliographically approved
Atta, K. & Guay, M. (2019). Adaptive amplitude fast proportional integral phasor extremum seeking control for a class of nonlinear system. Journal of Process Control
Open this publication in new window or tab >>Adaptive amplitude fast proportional integral phasor extremum seeking control for a class of nonlinear system
2019 (English)In: Journal of Process Control, ISSN 0959-1524, E-ISSN 1873-2771Article in journal (Refereed) In press
Abstract [en]

In this paper, we present a modification of the fast phasor extremum-seeking control for the fast optimization of a class of Wiener-Hammerstein nonlinear dynamical systems. The proposed technique provides a significant improvement of the closed-loop system's performance. This study introduces a new adaptive amplitude technique that is used to adaptively adjust the perturbation amplitude to a small predetermined value in a neighbourhood of the system's unknown optimal equilibrium. An analysis of the system demonstrates that semi-global practical stability analysis of the overall system to the unknown optimum is achieved. The effectiveness of the proposed approach is illustrated using numerical examples. The approach is also implemented for the optimal operation of a lean burn combustion system.

Keywords
Fast extremum-seeking control; Stability analysis; Wiener-Hammerstein system
National Category
Control Engineering
Research subject
Control Engineering
Identifiers
urn:nbn:se:ltu:diva-73304 (URN)10.1016/j.jprocont.2018.10.006 (DOI)
Available from: 2019-03-25 Created: 2019-03-25 Last updated: 2019-03-25
Atta, K. & Guay, M. (2019). Comment on “On stability and application of extremum seeking control without steady-state oscillation” [Automatica 68 (2016) 18–26] [Letter to the editor]. Automatica, 103, 580-581
Open this publication in new window or tab >>Comment on “On stability and application of extremum seeking control without steady-state oscillation” [Automatica 68 (2016) 18–26]
2019 (English)In: Automatica, ISSN 0005-1098, E-ISSN 1873-2836, Vol. 103, p. 580-581Article in journal, Letter (Refereed) Published
Abstract [en]

This correspondence revisits the results reported in a recent Automatica paper (Wang et al., 2016). We show that the claim of exponential stability of the extremum-seeking control system presented in Theorem 1 is not correct. An alternative stability analysis using the Lyapunov–Malkin theorem is considered. A counterexample is also presented.

Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
Adaptive control, Extremum seeking control, Steady-state oscillation
National Category
Control Engineering
Research subject
Control Engineering
Identifiers
urn:nbn:se:ltu:diva-73444 (URN)10.1016/j.automatica.2018.01.016 (DOI)
Available from: 2019-04-05 Created: 2019-04-05 Last updated: 2019-05-02Bibliographically approved
Guay, M. & Atta, K. (2018). A set-based model-free reinforcement learning design technique for nonlinear systems. Paper presented at 10th IFAC Symposium on Advanced Control of Chemical Processes (ADCHEM);JUL 25-27,2018;Shenyang,China.. IFAC-PapersOnLine, 51(18), 37-42
Open this publication in new window or tab >>A set-based model-free reinforcement learning design technique for nonlinear systems
2018 (English)In: IFAC-PapersOnLine, ISSN 1045-0823, E-ISSN 1797-318X, Vol. 51, no 18, p. 37-42Article in journal (Refereed) Published
Abstract [en]

In this study, we propose an extremum-seeking approach for the approximation of optimal control problems for unknown nonlinear dynamical systems. The technique combines a phasor extremum seeking controller with an reinforcement learning strategy. The learning approach is used to estimate the value function of an optimal control problem of interest. The phasor extremum seeking controller implements the approximate optimal controller. The approach is shown to provide reasonable approximations of optimal control problems without the need for a parameterization of the nonlinear control system. A simulation example are provided to demonstrate the effectiveness of the technique

Place, publisher, year, edition, pages
Elsevier, 2018
National Category
Control Engineering
Research subject
Control Engineering
Identifiers
urn:nbn:se:ltu:diva-71278 (URN)10.1016/j.ifacol.2018.09.242 (DOI)000446604800008 ()2-s2.0-85054426959 (Scopus ID)
Conference
10th IFAC Symposium on Advanced Control of Chemical Processes (ADCHEM);JUL 25-27,2018;Shenyang,China.
Note

Konferensartikel i tidskrift

Available from: 2018-10-19 Created: 2018-10-19 Last updated: 2018-10-19Bibliographically approved
Guay, M. & Atta, K. (2018). Dual mode extremum-seeking control via Lie-bracket averaging approximations. In: 2018 Annual American Control Conference (ACC): . Paper presented at 2018 Annual American Control Conference (ACC) June 27–29, 2018. Wisconsin Center, Milwaukee, USA (pp. 2972-2977). Piscataway, NJ: IEEE
Open this publication in new window or tab >>Dual mode extremum-seeking control via Lie-bracket averaging approximations
2018 (English)In: 2018 Annual American Control Conference (ACC), Piscataway, NJ: IEEE, 2018, p. 2972-2977Conference paper, Published paper (Refereed)
Abstract [en]

This paper proposes a dual mode extremum-seeking controller (ESC) design based on a Lie bracket averaging technique. The stability analysis demonstrates that the practical asymptotical stability of the unknown optimum can be achieved for autonomous and non-autonomous systems. The application of the technique for the solution of realtime optimization problem with time-varying optimum state trajectories is presented. A simulation study demonstrates the ability of the proposed technique to remove the input bias that results in the application of existing Lie bracket design techniques to dynamical control systems.

Place, publisher, year, edition, pages
Piscataway, NJ: IEEE, 2018
Series
Annual American Control Conference (ACC), E-ISSN 2378-5861
National Category
Control Engineering
Research subject
Control Engineering
Identifiers
urn:nbn:se:ltu:diva-71576 (URN)10.23919/ACC.2018.8430884 (DOI)2-s2.0-85052592737 (Scopus ID)978-1-5386-5429-3 (ISBN)978-1-5386-5428-6 (ISBN)978-1-5386-5427-9 (ISBN)
Conference
2018 Annual American Control Conference (ACC) June 27–29, 2018. Wisconsin Center, Milwaukee, USA
Available from: 2018-11-14 Created: 2018-11-14 Last updated: 2019-01-11Bibliographically approved
Atta, K., Johansson, A. & Gustafsson, T. (2017). Accuracy Improvement of Extremum Seeking Control. IEEE Transactions on Automatic Control, 62(4), 1952-1958, Article ID 7498657.
Open this publication in new window or tab >>Accuracy Improvement of Extremum Seeking Control
2017 (English)In: IEEE Transactions on Automatic Control, ISSN 0018-9286, E-ISSN 1558-2523, Vol. 62, no 4, p. 1952-1958, article id 7498657Article in journal (Refereed) Published
Abstract [en]

In this work, we present a modification for theclassic and phasor extremum seeking control algorithms in orderto improve the accuracy by removing or reducing the convergenceerror. The modulation signals were replaced by a sum of sinusoidsin order to remove the equilibrium shift in the controlled variableof the averaged system. The convergence error is calculated as afunction of the number of sinusoids used in the modulation signal.A simulation example is presented to illustrate the improvement.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers (IEEE), 2017
National Category
Control Engineering
Research subject
Control Engineering
Identifiers
urn:nbn:se:ltu:diva-62395 (URN)10.1109/TAC.2016.2584184 (DOI)000399033000031 ()2-s2.0-85018485239 (Scopus ID)
Note

Validerad; 2017; Nivå 2; 2017-03-29 (rokbeg)

Available from: 2017-03-10 Created: 2017-03-10 Last updated: 2018-07-10Bibliographically approved
Atta, K. & Guay, M. (2017). Fast proportional integral phasor extremum seeking control for a class of nonlinear system. Paper presented at 20th IFAC World Congress, Toulouse, France, 9-14 July 2017. IFAC-PapersOnLine, 50(1), 5724-5730
Open this publication in new window or tab >>Fast proportional integral phasor extremum seeking control for a class of nonlinear system
2017 (English)In: IFAC-PapersOnLine, ISSN 1045-0823, E-ISSN 1797-318X, Vol. 50, no 1, p. 5724-5730Article in journal (Refereed) Published
Abstract [en]

In this paper, we present a modification of the phasor extremum-seeking control for the fast optimization of a class of Wiener-Hammerstein nonlinear dynamical systems with a general strict unimodal nonlinearity. Based on the prior knowledge of the system’s relative order and number of non-minimum phase zeros, the proposed approach uses a high frequency perturbation signal and the phasor of the plant output to enable fast convergence of the overall system without the need for filters of the plant’s input and output. The extremum-seeking controller has two modes. In addition to the integral term, a proportional term is used to enable the application to very slow and integrating systems. Semi-global practical asymptotic stability analysis of the overall system to the unknown optimum is achieved. The effectiveness of the proposed approach is illustrated using numerical examples for different types of Wiener-Hammerstein systems.

Place, publisher, year, edition, pages
Elsevier, 2017
National Category
Control Engineering
Research subject
Control Engineering
Identifiers
urn:nbn:se:ltu:diva-66197 (URN)10.1016/j.ifacol.2017.08.1126 (DOI)000423964800440 ()2-s2.0-85031767381 (Scopus ID)
Conference
20th IFAC World Congress, Toulouse, France, 9-14 July 2017
Note

Konferensartikel i tidskrift

Available from: 2017-10-19 Created: 2017-10-19 Last updated: 2018-04-26Bibliographically approved
van Deventer, J., Derhamy, H., Atta, K. & Delsing, J. (2017). Service Oriented Architecture Enabling the 4rh Generation of District Heating (ed.). Paper presented at International Symposium on District Heating and Cooling : 04/09/2016 - 06/09/2016. Energy Procedia, 116, 500-509
Open this publication in new window or tab >>Service Oriented Architecture Enabling the 4rh Generation of District Heating
2017 (English)In: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 116, p. 500-509Article in journal (Refereed) Published
Abstract [en]

The 4th Generation of District Heating (4GDH) is a complex agglomeration of heat providers, distributors, and consumers that must be automatically, continuously managed and coordinated. It is a complex system of systems; a definition which we align to Maier’s architecting principles for systems-of-systems as collaborative systems. Wrapped in the idea of system of systems is the reality that the 4GDH systems’ descriptions and specifications are not currently all known. Nonetheless, the transition into the 4GDH is actual. We propose the use of two frameworks to secure a smooth metamorphosis and assure systems’ operation, maintenance, and evolution. The two frameworks are the Arrowhead Framework and the OPTi Framework. The first one enables system integration through Service Oriented Architecture (SOA) and the second one offers the overall system optimization with respect to all stakeholders. This paper uses the Model Based Systems Engineering (MBSE) tool SysML to model a district heating complex’s structures and behaviors from the concept level down to the sensors and actuators within a district heating substation where we apply the SOA technology based on the open Arrowhead Framework. We focus on the Arrowhead Framework’s core services, i.e. Service Registry, Authorization and Orchestration to clearly describe the interactions between the different service providers and consumers. Going back up from the sensors to the systems, it is clear that SOA is the architecture that will empower the 4GDH.

Place, publisher, year, edition, pages
Elsevier, 2017
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering Control Engineering
Research subject
Industrial Electronics; Control Engineering
Identifiers
urn:nbn:se:ltu:diva-64792 (URN)10.1016/j.egypro.2017.05.096 (DOI)000406743000048 ()2-s2.0-85028612928 (Scopus ID)
Conference
International Symposium on District Heating and Cooling : 04/09/2016 - 06/09/2016
Projects
OPTi Optimisation of District Heating Cooling systems, OPTi
Funder
EU, Horizon 2020, 649796
Note

2017-07-05 (andbra);Konferensartikel i tidskrift

Available from: 2017-07-05 Created: 2017-07-05 Last updated: 2018-07-10Bibliographically approved
Atta, K., Johansson, A. & Gustafsson, T. (2016). On the stability analysis of phasor and classic extremum seeking control (ed.). Paper presented at . Systems & control letters (Print), 91, 55-62
Open this publication in new window or tab >>On the stability analysis of phasor and classic extremum seeking control
2016 (English)In: Systems & control letters (Print), ISSN 0167-6911, E-ISSN 1872-7956, Vol. 91, p. 55-62Article in journal (Refereed) Published
Abstract [en]

In this work we present a semi-global practical asymptotic stability analysis for phasor extremum seeking control with a general non-linear dynamic system. With the same technique applied to the classic band pass filter algorithm, we present a more relaxed (less constrained) semi-global practical asymptotic stability condition compared to earlier work. The results are based on a non approximated averaging for both control techniques.

National Category
Control Engineering
Research subject
Control Engineering
Identifiers
urn:nbn:se:ltu:diva-12684 (URN)10.1016/j.sysconle.2016.02.007 (DOI)000375630000009 ()2-s2.0-84961794725 (Scopus ID)bd90bbac-c727-44bd-93c0-26f1097bb9b3 (Local ID)bd90bbac-c727-44bd-93c0-26f1097bb9b3 (Archive number)bd90bbac-c727-44bd-93c0-26f1097bb9b3 (OAI)
Note
Validerad; 2016; Nivå 2; 20160318 (andbra)Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2018-07-10Bibliographically approved
Atta, K., Birk, W., Hostettler, R. & Johansson, A. (2016). Phasor extremum seeking control with adaptive perturbation amplitude. In: 2016 IEEE 55th Conference on Decision and Control, CDC 2016: . Paper presented at 55th IEEE Conference on Decision and Control, CDC 2016, Las Vegas, United States, 12-14 December 2016 (pp. 7069-7074). Piscataway, NJ: Institute of Electrical and Electronics Engineers (IEEE), Article ID 7799358.
Open this publication in new window or tab >>Phasor extremum seeking control with adaptive perturbation amplitude
2016 (English)In: 2016 IEEE 55th Conference on Decision and Control, CDC 2016, Piscataway, NJ: Institute of Electrical and Electronics Engineers (IEEE), 2016, p. 7069-7074, article id 7799358Conference paper, Published paper (Refereed)
Abstract [en]

In this paper, we propose a perturbation amplitude adaption scheme for phasor extremum seeking control based on the plant's estimated gradient. By using phasor extremum seeking instead of classical extremum seeking, the problem of algebraic loops in the controller formulation is avoided. Furthermore, a stability analysis for the proposed method is provided, which is the first stability analysis for extremum seeking controllers using adaptive amplitudes. The proposed method is illustrated using numerical examples and it is found that changes in optimum can be tracked accurately while the steady-state perturbations can be reduced significantly.

Place, publisher, year, edition, pages
Piscataway, NJ: Institute of Electrical and Electronics Engineers (IEEE), 2016
Series
IEEE Conference on Decision and Control, E-ISSN 0743-1546
National Category
Signal Processing
Research subject
Signal Processing
Identifiers
urn:nbn:se:ltu:diva-61868 (URN)10.1109/CDC.2016.7799358 (DOI)000400048107044 ()2-s2.0-85010747991 (Scopus ID)9781509018376 (ISBN)
Conference
55th IEEE Conference on Decision and Control, CDC 2016, Las Vegas, United States, 12-14 December 2016
Available from: 2017-02-08 Created: 2017-02-08 Last updated: 2017-12-15Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-9901-5776

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