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Lucchese, R. & Johansson, A. (2019). On energy efficient flow provisioning in air-cooled data servers. Control Engineering Practice, 89, 103-112
Open this publication in new window or tab >>On energy efficient flow provisioning in air-cooled data servers
2019 (English)In: Control Engineering Practice, ISSN 0967-0661, E-ISSN 1873-6939, Vol. 89, p. 103-112Article in journal (Refereed) Published
Abstract [en]

This study considers how to efficiently manage the thermal state of data servers by provisioning their cooling airflow dynamically. It introduces a thermal network framework that is tailored to capture the temperature dynamics of the on-board thermal inertiae. On top of this modeling, it devises LeakageCooling, a novel flow provisioning controller that balances the temperature dependent leakage dissipation within the electronic chips and the power consumed by the local fans to produce the cooling airflow. The prediction capabilities of the proposed modeling and the overall control performance are assessed over several relevant experimental scenarios on an Open Compute Windmill V2 server.

Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
Server thermal models, Server thermal management, Controlled flow provisioning, Controlled data center cooling
National Category
Control Engineering
Research subject
Control Engineering
Identifiers
urn:nbn:se:ltu:diva-75057 (URN)10.1016/j.conengprac.2019.05.019 (DOI)2-s2.0-85066323953 (Scopus ID)
Note

Validerad;2019;Nivå 2;2019-06-27 (johcin)

Available from: 2019-06-27 Created: 2019-06-27 Last updated: 2019-06-27Bibliographically 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., 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
Sayyaddelshad, S., Johansson, A., Darouach, M. & Gustafsson, T. (2016). Robust state estimation and unknown inputs reconstruction for a class of nonlinear systems: multiobjective approach (ed.). Paper presented at . Automatica, 64, 1-7
Open this publication in new window or tab >>Robust state estimation and unknown inputs reconstruction for a class of nonlinear systems: multiobjective approach
2016 (English)In: Automatica, ISSN 0005-1098, E-ISSN 1873-2836, Vol. 64, p. 1-7Article in journal (Refereed) Published
Abstract [en]

We consider a novel method to design H-infinity observers for a class of uncertain nonlinear systems subject to unknown inputs. First, the main system dynamics are rewritten as an augmented system with state vector including both the state vector of the main system and the unknown inputs. Then, we design a H-infinity reduced-order observer to estimate both state variables and unknown inputs simultaneously. Based on a Lyapunov functional, we derive a sufficient condition for existence of the designed observer which requires solving a nonlinear matrix inequality. To facilitate the observer design, the achieved condition is formulated in terms of a set of linear matrix inequalities (LMI). By extending the proposed method to a multiobjective optimization problem, the maximum bound of the uncertainty and the minimum value of the disturbance attenuation level are found. Finally, the proposed observer is illustrated with an example.

Keywords
Information technology - Automatic control, Informationsteknik - Reglerteknik
National Category
Control Engineering
Research subject
Control Engineering
Identifiers
urn:nbn:se:ltu:diva-3452 (URN)10.1016/j.automatica.2015.10.051 (DOI)000368967000001 ()2-s2.0-84951753244 (Scopus ID)14661358-2de9-42eb-87e4-fc5c24c5d160 (Local ID)14661358-2de9-42eb-87e4-fc5c24c5d160 (Archive number)14661358-2de9-42eb-87e4-fc5c24c5d160 (OAI)
Note
Validerad; 2015; Nivå 2; 20151027 (salsay)Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2018-07-10Bibliographically approved
Atta, K., Johansson, A. & Gustafsson, T. (2015). Extremum seeking control based on phasor estimation (ed.). Paper presented at . Systems & control letters (Print), 85, 37-45
Open this publication in new window or tab >>Extremum seeking control based on phasor estimation
2015 (English)In: Systems & control letters (Print), ISSN 0167-6911, E-ISSN 1872-7956, Vol. 85, p. 37-45Article in journal (Refereed) Published
Abstract [en]

We present an extremum seeking control algorithm based on the estimation of the phasor of the perturbation frequency in the output of the plant. The phasor estimator is based on a continuous time Kalman filter, which is reduced into a variable gain observer by explicitly solving the special case of the Riccati equation. Local stability of the proposed al- gorithm for general non-linear dynamic systems using averaging and singular perturbations is presented for the single input case. The advantage of the presented algorithm is that it can be used on plants with large and even variable phase lag.

National Category
Control Engineering
Research subject
Control Engineering; Intelligent industrial processes (AERI)
Identifiers
urn:nbn:se:ltu:diva-10781 (URN)10.1016/j.sysconle.2015.08.010 (DOI)000364884300006 ()2-s2.0-84944041663 (Scopus ID)9a49e75c-e3e9-47ab-8626-7390e4551bd6 (Local ID)9a49e75c-e3e9-47ab-8626-7390e4551bd6 (Archive number)9a49e75c-e3e9-47ab-8626-7390e4551bd6 (OAI)
Note
Validerad; 2015; Nivå 2; 20150908 (tgu)Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2018-07-10Bibliographically approved
Atta, K., Johansson, A., Cervantes, M. J. & Gustafsson, T. (2015). Maximum power point tracking for micro hydro power plants using extremum seeking control (ed.). In: (Ed.), (Ed.), 2015 IEEE International Conference on Control Applications (CCA 2015): Sydney, Australia, September 21-23 2015 (pp. 1874-1879). Piscataway, NJ: IEEE Communications Society, Article ID 7320883.
Open this publication in new window or tab >>Maximum power point tracking for micro hydro power plants using extremum seeking control
2015 (English)In: 2015 IEEE International Conference on Control Applications (CCA 2015): Sydney, Australia, September 21-23 2015, Piscataway, NJ: IEEE Communications Society, 2015, p. 1874-1879, article id 7320883Conference paper, Published paper (Refereed)
Abstract [en]

In this work, we propose using extremum seeking control (ESC) as a tool for maximum power point tracking in micro hydro power plants. The phasor ESC, which is based on estimating the phasor of the plant output at the perturbation frequency, was modified by stimating the phasors of multiple harmonics of this frequency. This modification will improve the performance of ESC by reducing the luctuations in control variables that may appear in noisy environments as a result of high-amplitude perturbation signals. A test rig was used to experimentally verify the proposed approach and to demonstrate the usability of ESC in hydro power plants.

Place, publisher, year, edition, pages
Piscataway, NJ: IEEE Communications Society, 2015
Series
I E E E International Conference on Control Applications. Proceedings, ISSN 1085-1992
Keywords
Extremum Seeking Control, Maximum Power Point Tracking, Small Hydro Power Plant, Fluctuation Reductions
National Category
Control Engineering Fluid Mechanics and Acoustics
Research subject
Control Engineering; Fluid Mechanics
Identifiers
urn:nbn:se:ltu:diva-38810 (URN)10.1109/CCA.2015.7320883 (DOI)2-s2.0-84964371828 (Scopus ID)d51cc8b3-ee8a-42cd-9040-7d4488e75f7b (Local ID)978-1-4799-7787-1 (ISBN)d51cc8b3-ee8a-42cd-9040-7d4488e75f7b (Archive number)d51cc8b3-ee8a-42cd-9040-7d4488e75f7b (OAI)
Note
Validerad; 2016; Nivå 1; 20150928 (khaatt)Available from: 2016-10-03 Created: 2016-10-03 Last updated: 2018-07-10Bibliographically approved
Birk, W., Castaño, M. & Johansson, A. (2014). An Application Software For Visualization and Control Configuration Selection of Interconnected Processes (ed.). Paper presented at . Control Engineering Practice, 26, 188-200
Open this publication in new window or tab >>An Application Software For Visualization and Control Configuration Selection of Interconnected Processes
2014 (English)In: Control Engineering Practice, ISSN 0967-0661, E-ISSN 1873-6939, Vol. 26, p. 188-200Article in journal (Refereed) Published
Abstract [en]

This paper presents a new application software for control conguration selection of interconnected industrial processes,called ProMoVis. Moreover, ProMoVis is able to visualize process models and process layout at the physical leveltogether with the control system dynamics. The software consists of a builder part where the visual representationof the interconnected process is created and an analyzer part where the process is analyzed using dierent controlconguration selection tools.The conceptual idea of the software is presented and the subsequent design and implementation of ProMoVis isdiscussed. The implemented analysis methods are briey described including their usage and implementation aspects.The use of ProMoVis is demonstrated by an application study on the stock preparation process at SCA Obbola AB,Sweden. The results of this study are compared with the currently used control strategy.The study indicates that ProMoVis introduces a systematic and comprehensive way to perform control congurationselection. ProMoVis has been released under the Apache Open Source license.

National Category
Control Engineering
Research subject
Control Engineering
Identifiers
urn:nbn:se:ltu:diva-9890 (URN)10.1016/j.conengprac.2013.12.012 (DOI)000334482800017 ()2-s2.0-84897690252 (Scopus ID)8963ead5-6bda-4245-bbc6-275b8db6663f (Local ID)8963ead5-6bda-4245-bbc6-275b8db6663f (Archive number)8963ead5-6bda-4245-bbc6-275b8db6663f (OAI)
Projects
Metoder för strukturell optimering av styrning i massatillverkning – MeSTA, SCOPE Norra
Note
Validerad; 2014; 20140107 (wolfgang)Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2018-07-10Bibliographically approved
Atta, K., Johansson, A. & Gustafsson, T. (2014). Control oriented modeling of flow and size distribution in cone crushers (ed.). Paper presented at . Minerals Engineering, 56, 81-90
Open this publication in new window or tab >>Control oriented modeling of flow and size distribution in cone crushers
2014 (English)In: Minerals Engineering, ISSN 0892-6875, E-ISSN 1872-9444, Vol. 56, p. 81-90Article in journal (Refereed) Published
Abstract [en]

This work presents a dynamic model for prediction of flow and output size distribution of cone crushers. The main purpose of the model is for simulation of closed-loop control using the Closed Side Setting (CSS) and the eccentric speed (ω) as manipulated variables. The idea of modeling crushers as cascaded zones is adopted throughout this work. The capacity, the length, the stroke, and the compression ratio of each zone are taken into consideration. Simulation results are presented in the form of the Crusher Performance Map (CPM) and the dynamic response for production of different size classes to steps input in ω and CSS. The simulations also include operation with recycling of oversize output, as well as the input of mixed materials. As an example, closed-loop control of the ratio of the large-size output to the total size output was simulated.

National Category
Control Engineering
Research subject
Control Engineering
Identifiers
urn:nbn:se:ltu:diva-2401 (URN)10.1016/j.mineng.2013.10.031 (DOI)000331432300009 ()2-s2.0-84888862955 (Scopus ID)004e69f1-d5f5-4749-a540-be9d696ad2f0 (Local ID)004e69f1-d5f5-4749-a540-be9d696ad2f0 (Archive number)004e69f1-d5f5-4749-a540-be9d696ad2f0 (OAI)
Note
Validerad; 2014; 20131128 (andbra)Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2018-07-10Bibliographically approved
Sayyaddelshad, S., Johansson, A., Darouach, M. & Gustafsson, T. (2014). H∞ filter design for state estimation and unknown inputs reconstruction of a class of nonlinear systems (ed.). In: (Ed.), (Ed.), 19th IFAC World Congress on International Federation of Automatic Control: IFAC 2014, Cape Town, South Africa 24 - 29 August 2014. Paper presented at IFAC World Congress : 25/08/2014 - 29/08/2014 (pp. 61-66).
Open this publication in new window or tab >>H∞ filter design for state estimation and unknown inputs reconstruction of a class of nonlinear systems
2014 (English)In: 19th IFAC World Congress on International Federation of Automatic Control: IFAC 2014, Cape Town, South Africa 24 - 29 August 2014, 2014, p. 61-66Conference paper, Published paper (Refereed)
Abstract [en]

We consider a novel method to design a H∞ filter for a class of nonlinear systems subject to unknown inputs. First, we rewrite the system dynamics as a descriptor system. Then, we design a robust H∞ reduced-order filter to estimate both state variables and unknown inputs at the same time. Based on a Lyapunov functional, we derive a sufficient condition for existence of the designed filter which requires solving a nonlinear matrix inequality. The achieved condition is further formulated in terms of a linear matrix inequality (LMI) that is straightforward to solve by popular methods. Finally, the proposed filter is illustrated with an example.

Series
IFAC proceedings series, ISSN 0741-1146 ; 47:3
National Category
Control Engineering
Research subject
Control Engineering
Identifiers
urn:nbn:se:ltu:diva-35562 (URN)10.3182/20140824-6-ZA-1003.02363 (DOI)a22bed4f-a498-4c94-affa-9ae1ac1fb551 (Local ID)a22bed4f-a498-4c94-affa-9ae1ac1fb551 (Archive number)a22bed4f-a498-4c94-affa-9ae1ac1fb551 (OAI)
Conference
IFAC World Congress : 25/08/2014 - 29/08/2014
Note
Godkänd; 2014; 20140401 (tgu)Available from: 2016-09-30 Created: 2016-09-30 Last updated: 2017-12-15Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0001-8893-4809

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