Change search
Refine search result
1 - 30 of 30
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 1.
    Atta, Khalid
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Extremum Seeking Control: Stability, Accuracy, and Applications2015Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    In many applications, there is a variable that indicates the overall performance and that must be maximized, such as the output of a hydro power turbine or a mineral processing plant, or that must be minimized, such as CO2 emissions or the consumption of resources. Extremization of this variable (maximization or minimization) through adjusting the influencing manipulated variables is occasionally required without prior knowledge of the optimal values of the manipulated variables or of the optimized variable. Extremum seeking control (ESC), which is an on-line concept for the optimization of dynamic systems, can achieve this task.Many types of ESC have been proposed in the literature, and the majority of these approaches are based on the gradient descent optimization method. The most common type of ESC is the classic ESC, which is based on adding a sinusoidal perturbation to the manipulated variables followed by the use of a band pass filter (BPF) to find an estimate of the gradient of the output with respect to the input. The plant is then extremized by adjusting the manipulated variables to make this estimate approach zero.In this work, an alternative approach called phasor ESC is proposed, which is based on estimating the phasor of the plant output at the perturbation frequency rather than the gradient. Stability analysis of the phasor ESC is presented, including local and semi-global practical asymptotic stability for general non-linear dynamic plants. As an improvement of the existing stability analysis of the classic ESC, a less constrained semi-global practical asymptotic stability condition is also presented. In perturbation-based ESC, the output will continuously oscillate due to the input perturbation. As noted in the literature, the averaged system may not converge to the optimum point, and an average offset from the optimal value will emerge. This offset is negligible in the case of a small perturbation signal but will increase as the perturbation amplitude increases. In this work, a modification for the classic ESC and phasor ESC is proposed that improves the accuracy by reducing this offset. Two applications of ESC are considered: cone crushers and hydro power plants. Cone crushers are used for reducing the size of minerals and are considered to be a key component of many mineral processing plants. On-line optimization of the throughput is proposed based on the concept of ESC. A novel model of cone crushers is presented that can predict the flow and the size distribution of the output as a function of the primary manipulated variables, and simulations of ESC control on this model are presented.For hydro power plants, which are considered to be the most important source of renewable energy, phasor ESC is proposed for constructing and correcting the combinator, which ensures the optimal and efficient operation of the Kaplan turbine. Moreover, phasor ESC is proposed as a tool for maximum power point tracking in micro hydro plants by manipulating the turbine speed, and a test rig is used to conduct an experiment to validate this approach.

  • 2.
    Atta, Khalid
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Modeling and on-line optimization of cone crushers2013Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    This licentiate thesis deals with the Modeling, Control, and On-line optimization of Cone Crushers. Cone crushers are used for size reduction of minerals and are considered as a central element in many mineral processing plants. It consists of a cone rotating eccentrically inside a larger bowl and the particles are crushed in the cavity between these. In spite of its simple construction, the cone crusher represents a complex system from a modeling point of view, as its operation comprises many physical actions that are combined together to give the overall behavior.The main purpose of the work is to have a dynamic model that can predict the ow and the size distribution of the crusher as a function of the main manipulated variables so that realistic simulation of closed loop control strategies can be achieved. The model is based on rst principles and includes many factors that are known to aect the operation of the crusher, e.g operation of the crusher with two dierent materials. For the control of the crusher, a number of dierent approaches were considered. First, a simple PI controller of the percentage of large material in the output produced was simulated. It is known and also predicted by the model that the cone crusher's total throughput depends on the Eccentric Speed, and exhibits a quasi-concave response with respect to this variable.On-line optimization of the throughput is suggested to be based on the concept of Extremum Seeking Control (ESC).Two dierent methods of ESC were applied. The classic Band Pass Filters based approach, and the Extended Kalman Filter Based approach. Both methods were modied in order to achieve improved performance. These modications can be applied on other plants as well. Simulations of the closed loop for the two methods have demonstrated the applicability of ESC for optimizing the crusher on-line. The optimum operating point was reached in all cases, leading to improvement of the performance of the crusher.

  • 3.
    Atta, Khalid
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Birk, Wolfgang
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Utilization of Generic Consumer Modeling in Planning and Optimization of District Heating and Cooling Systems2018In: Proceedings of the 21st Nordic Process Control Workshop / [ed] Kurt-Erik Häggblom, 2018Conference paper (Other academic)
    Abstract [en]

    District heating and cooling (DHC) networks are large scale complex systems which aregenerally difficult to operate and optimize. The large thermal inertia in the systems leadsto long reaction times on changes at the consumer side, which means that forecasting ofconsumer behaviour is a needed tool for efficient operation. Within the European Unionmany major research project target the energy reduction on the consumption side and peakload management while maintaining customer satisfaction.The optimal operation of a DHC network can therefore be considered as an interestingarea of investigation due to a number of aspects, like (i) the vast amount of the energy that is distributed by these networks, (ii) the demand to provide a better quality of services by the operators of these networks, and (iii) compliance with new environmental regulations. In this presentation, we discuss a possible conceptual method that utilizes a simpliedstatic model of different types of consumers in the network to design a decision supportsystem that will guide the operators of the DHC network to optimally operate the networkwith different operational scenarios that include but not limited to: (i) energy consumptionminimization, (ii) economic operation, (iii) peak load reduction/shifting, and (iv) environmentally friendly operation. In its current form, the operator will be informed, while in thefuture these actions could be fully automated in a closed loop context.The DHC network in Luleå, Sweden will be used as a test case which represents a typicalmedium size network. The case has a number of properties which motivate its study likee.g. the distributed generation possibilities, the geographical distribution of the consumers,and the different types of consumers in the area. The presentation will be concluded with anoutlook on future tracks of research and development

  • 4.
    Atta, Khalid
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Birk, Wolfgang
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Hostettler, Roland
    Department of Electrical Engineering and Automation, Aalto University.
    Johansson, Andreas
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Phasor extremum seeking control with adaptive perturbation amplitude2016In: 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 (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.

  • 5.
    Atta, Khalid
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Guay, Martin
    Department of Chemical Engineering, Queens University, Kingston, ON K7L 3N6, Canada.
    Adaptive amplitude fast proportional integral phasor extremum seeking control for a class of nonlinear system2019In: Journal of Process Control, ISSN 0959-1524, E-ISSN 1873-2771, Vol. 83, p. 147-154Article in journal (Refereed)
    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.

  • 6.
    Atta, Khalid
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Guay, Martin
    Department of Chemical Engineering, Queen’s University, Kingston, ON, Canada.
    Comment on “On stability and application of extremum seeking control without steady-state oscillation” [Automatica 68 (2016) 18–26]2019In: Automatica, ISSN 0005-1098, E-ISSN 1873-2836, Vol. 103, p. 580-581Article in journal (Refereed)
    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.

  • 7.
    Atta, Khalid
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Guay, Martin
    Department of Chemical Engineering, Queens University, Kingston, ON.
    Fast proportional integral phasor extremum seeking control for a class of nonlinear system2017In: IFAC-PapersOnLine, ISSN 1045-0823, E-ISSN 1797-318X, Vol. 50, no 1, p. 5724-5730Article in journal (Refereed)
    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.

  • 8.
    Atta, Khalid
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Guay, Martin
    Queen's University.
    Lucchese, Riccardo
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    A geometric phasor extremum seeking control approach with measured constraints2019Conference paper (Refereed)
  • 9.
    Atta, Khalid
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Johansson, Andreas
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Cervantes, Michel J.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Gustafsson, Thomas
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Maximum power point tracking for micro hydro power plants using extremum seeking control2015In: 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 (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.

  • 10.
    Atta, Khalid
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Johansson, Andreas
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Cervantes, Michel J.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Gustafsson, Thomas
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Phasor Extremum Seeking and its Application in Kaplan Turbine Control2014In: 2014 IEEE International Conference on Control Applications (CCA 2014): Juan Les Antibes, France, 8 -10 October 2014, Piscataway, NJ: IEEE Communications Society, 2014, p. 298-303Conference paper (Refereed)
    Abstract [en]

    The Combinator is an important part in Kaplan turbine control. It ensures that the turbine will operate in an optimum way, in terms of maximum efficiency of the plant. This work suggests a new sinusoidal perturbation based extremum seeking algorithm based on the phasor of the output. We propose to use this algorithm for generating the required data to build and correct the combinator. Simulations are presented showing the applicability of the proposed methods.

  • 11.
    Atta, Khalid
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Johansson, Andreas
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Guay, Martin
    Department of Chemical Engineering, Queens University, Kingston, ON.
    On the Generalization and Stability Analysis of Pareto Seeking Control2018In: IEEE Control Systems Letters, E-ISSN 2475-1456, Vol. 2, no 1, p. 145-150Article in journal (Refereed)
    Abstract [en]

    In this letter, we address a multi-objective on-line optimization problem for unknown dynamical systems by providing a generalization of the Pareto seeking controller (PSC). The idea of the PSC is to drive the system to the Pareto front in the absence of knowledge of the values of the objectives or the input values to achieve Pareto optimality. Two special cases are presented, for two objectives and three objectives. A stability analysis is presented for the case of two objectives and two inputs, which shows that the controller practically drives the system into the neighborhood of the Pareto front, for any initial condition. Two simulation examples for the special cases are also presented

  • 12.
    Atta, Khalid
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Johansson, Andreas
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Gustafsson, Thomas
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Accuracy Improvement of Extremum Seeking Control2017In: 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)
    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.

  • 13.
    Atta, Khalid
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Johansson, Andreas
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Gustafsson, Thomas
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Control oriented modeling of flow and size distribution in cone crushers2014In: Minerals Engineering, ISSN 0892-6875, E-ISSN 1872-9444, Vol. 56, p. 81-90Article in journal (Refereed)
    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.

  • 14.
    Atta, Khalid
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Johansson, Andreas
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Gustafsson, Thomas
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Extremum seeking control based on phasor estimation2015In: Systems & control letters (Print), ISSN 0167-6911, E-ISSN 1872-7956, Vol. 85, p. 37-45Article in journal (Refereed)
    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.

  • 15.
    Atta, Khalid
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Johansson, Andreas
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Gustafsson, Thomas
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    On the stability analysis of phasor and classic extremum seeking control2016In: Systems & control letters (Print), ISSN 0167-6911, E-ISSN 1872-7956, Vol. 91, p. 55-62Article in journal (Refereed)
    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.

  • 16.
    Atta, Khalid
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Johansson, Andreas
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Gustafsson, Thomas
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    On-Line Optimization of Cone Crushers using Extremum-Seeking Control2013In: 2013 IEEE Multi-conference on Systems and Control (Conference on Control Applications), Hyderabad, India, August 28-30, 2013, 2013, p. 1054-1060Conference paper (Refereed)
    Abstract [en]

    This article demonstrates the ability of on-lineoptimization of cone crushers, specifically maximization of thetotal throughput of the crusher by adjusting the eccentric speed(ω). The on-line optimization was based on the Extremum-Seeking Control (ESC) approach, which is advantageous whenoptimizing systems with unknown time varying characteristics.Two types of gradient based approaches are tested in simulation,the traditional Band-pass filters method and a methodutilizing the Extended Kalman Filter (EKF). Both methodsperform satisfactory, demonstrating the good potential of ESCfor online-optimization of cone crushers. To deal with unwantedbehavior of the EKF based approach for situations when thegradient is not correctly estimated, a modification is suggestedbased on detecting this condition and accommodating for it.

  • 17.
    Atta, Khalid
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Johansson, Andreas
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Gustafsson, Thomas
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Pareto Seeking Control: On-line multi-objective optimization of dynami systems2014Conference paper (Other academic)
  • 18.
    Atta, Khalid
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Johansson, Andreas
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Gustafsson, Thomas
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Pareto Seeking Control: On-line multi-objective optimization of dynami systems2014Conference paper (Refereed)
  • 19.
    Birk, Wolfgang
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Atta, Khalid
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Towards Autonomous Synthesis of Building Substation Control Loops2016In: IEEE International Conference on Smart Grid Communications (SmartGridComm) 2016, Piscataway, NJ, 2016, p. 38-44, article id 7778735Conference paper (Refereed)
    Abstract [en]

    The main contribution of this paper is to study the feasibility of an automated approach to the assessment and synthesis of control loops in substations of a district heating and cooling system. The low-level controllers in substation are usually PID-type controllers and can not easily be changed. Moreover, the tuning of these controllers is often done in an ad-hoc manner and remains in the initial tuning despite changes in the substation over their operational life. Consequently, insufficient control performance due to false tuning can be misinterpreted as a hardware issue and lead to unnecessary replacement of parts.

    In order to solve this problem, the paper proposes an approach to assess the control loop performance based on logged data from substations, and to subsequently tune the current substation controllers, when no hardware issues are detected. The approach is applied to a well-known building substation model in simulation, which indicates that the approach is feasible.

    Analysis of acquired data from a number of substations in the DHC system of Luleå Energi AB, provides evidence for the problem and how the approach can be applied in its future implementation. Moreover, a number of challenges and future work are indicated.

  • 20.
    Birk, Wolfgang
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Atta, Khalid
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Udén, Fredrik
    Improving District Heating System Operation through Control Configuration Selection and Adaptive Control2019In: 2019 18th European Control Conference (ECC), 2019, p. 2944-2949Conference paper (Refereed)
  • 21. Guay, Martin
    et al.
    Atta, Khalid
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    A backstepping controller design technique for a class of cascaded nonlinear systems with unknown dynamics2019In: 2019 American Control Conference (ACC), 2019, p. 3093-3098Conference paper (Refereed)
  • 22.
    Guay, Martin
    et al.
    Department of Chemical Engineering, Queen's University, Kingston, ON, Canada.
    Atta, Khalid
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    A set-based model-free reinforcement learning design technique for nonlinear systems2018In: IFAC-PapersOnLine, ISSN 1045-0823, E-ISSN 1797-318X, Vol. 51, no 18, p. 37-42Article in journal (Refereed)
    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

  • 23.
    Guay, Martin
    et al.
    Department of Chemical Engineering, Queen's University, Kingston, ON, Canada.
    Atta, Khalid
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    A set-based model-free reinforcement learning design technique for nonlinear systems2019In: International Journal of Adaptive Control and Signal Processing, ISSN 1099-1115, Vol. 33, no 2, p. 315-334Article in journal (Refereed)
    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.

  • 24.
    Guay, Martin
    et al.
    Department of Chemical Engineering, Queen's University, Kingston, ON, K7L 3N6, Canada.
    Atta, Khalid
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    An extremum-seeking control observer design technique for nonlinear systems2018In: 2017 IEEE 56th Conference on Decision and Control, CDC, Piscataway, NJ: Institute of Electrical and Electronics Engineers (IEEE), 2018Conference paper (Refereed)
    Abstract [en]

    In this study, we propose an extremum-seeking control approach for the design on nonlinear observers for a general class of detectable nonlinear systems. The extremum-seeking control approach provides a mechanism to compute an observer gain that minimizes the squared output error. The technique extends and generalizes an earlier extremum seeking control observer design approach that was limited to systems in observer normal form with a linear state to output map. The analysis provides conditions for the application of the technique and establishes a semi-global practical stability property of the error dynamics. Two simulation examples are presented to demonstrate the effectiveness of the technique

  • 25.
    Guay, Martin
    et al.
    Queen's University, Department of Chemical Engineering, Kingston, ON, K7L 3N6, Canada.
    Atta, Khalid
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Dual mode extremum-seeking control via Lie-bracket averaging approximations2018In: 2018 Annual American Control Conference (ACC), Piscataway, NJ: IEEE, 2018, p. 2972-2977Conference 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.

  • 26. Guay, Martin
    et al.
    Atta, Khalid
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Extremum seeking regulator for a class of unknown SISO nonlinear systems2019In: 2019 American Control Conference (ACC), 2019, p. 3032-3037Conference paper (Refereed)
  • 27.
    Lucchese, Riccardo
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Lionello, Michele
    Università degli Studi di Padova.
    Rampazzo, Mirco
    Università degli Studi di Padova.
    Guay, Martin
    Queen's University.
    Atta, Khalid
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Gradient-free optimization of data center cooling using Extremum Seeking2019Conference paper (Other academic)
  • 28.
    Lucchese, Riccardo
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Lionello, Michele
    Università degli Studi di Padova.
    Rampazzo, Mirco
    Università degli Studi di Padova.
    Guay, Martin
    Queen's University.
    Atta, Khalid
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Newton-like phasor extremum seeking control with application to cooling data centers2019Conference paper (Refereed)
  • 29.
    van Deventer, Jan
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Derhamy, Hasan
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Atta, Khalid
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Delsing, Jerker
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Service Oriented Architecture Enabling the 4rh Generation of District Heating2017In: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 116, p. 500-509Article in journal (Refereed)
    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.

  • 30.
    van Deventer, Jan
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Derhamy, Hasan
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Atta, Khalid
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Delsing, Jerker
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Service Oriented Architecture Enabling the 4rh Generation of District Heating2016In: The 15th International Symposium on District Heating and CoolingSeptember 4-7, 2016, Seoul, Republic of Korea, 2016Conference paper (Refereed)
    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.

1 - 30 of 30
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf