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  • 151.
    Brusell, Angelica
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Andrikopoulos, Georgios
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Nikolakopoulos, George
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Novel considerations on the negative pressure adhesion of electric ducted fans: An experimental study2017Ingår i: 2017 25th Mediterranean Conference on Control and Automation, MED 2017, Piscataway, NJ: Institute of Electrical and Electronics Engineers (IEEE), 2017, s. 1404-1409, artikel-id 7984315Konferensbidrag (Refereegranskat)
    Abstract [en]

    In this article, the potential of utilizing an Electric Ducted Fan (EDF) as an adhesion actuator is investigated in detail, where an experimental setup is implemented for evaluating the EDF's ability to adhere to a test surface through negative pressure generation. Different design variables and modifications to the original EDF structure are tested, while their impact on the adhesion efficiency is experimentally evaluated. The presented investigation acts as a preliminary study to the goal of incorporating the resulting optimized negative pressure-based actuation method in a wall-climbing robot for inspection of aircraft fuselages

  • 152.
    Brännström, Mattias
    et al.
    Volvo Car Corporation.
    Levin, Daniel
    Volvo Car Corporation.
    Birk, Wolfgang
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Grante, Christian
    Volvo Car Corporation.
    Jansson, Jonas
    VTI - Statens väg-och transportforskningsinstitut.
    Hultén, Johan
    Modelon AB.
    Rear end collision mitigation system for an automotive vehicle: patent pendingPatent (Övrig (populärvetenskap, debatt, mm))
    Abstract [en]

    The present invention relates to a system (1) and method for autonomous rear impact mitigation in a host vehicle (2) having a brake system (4) and a steering system (5). The relative motion parameters between the host vehicle (2) and a second vehicle (11) behind the host vehicle (2) are established. While the host vehicle (2) has a positive velocity, the brake system (4) of the host vehicle (2) is selectively activated based on the determined relative motion parameters.

  • 153.
    Böling, Jari M.
    et al.
    Department of Engineering, Åbo Akademi.
    Mäkilä, Pertti
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    On control relevant criteria in H∞ identification1998Ingår i: IEEE Transactions on Automatic Control, ISSN 0018-9286, E-ISSN 1558-2523, Vol. 43, nr 5, s. 694-700Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper proposes a technique for using control relevant criteria in H∞ identification. The work reported here has its background in a desire to understand the closed-loop versus open-loop issue in control relevant identification. The proposed technique has some features in common with the iterative closed-loop Schrama scheme, but is constructed so as to be able to obtain control relevant reduced complexity models also directly from open-loop data (for stable systems). It is demonstrated that the proposed technique solves, with the initial open-loop data only, the examples treated earlier in the literature using the iterative closed-loop Schrama scheme

  • 154.
    Cancila, Daniela
    et al.
    CEA France.
    Nuzzo, Valeria
    ECE France.
    Stoycheva, Milena
    University of Trento, Italy.
    Birk, Wolfgang
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Asplund, Fredrik
    KTH Royal Institute of Technology.
    Torngren, Martin
    KTH Royal Institute of Technology.
    Experiences and reflections on three years of CPS Summer schools within EIT Digital2016Ingår i: WESE '16: Proceedings of the 2016 Workshop on Embedded and Cyber-Physical Systems Education, New York: ACM Digital Library, 2016, artikel-id 7Konferensbidrag (Refereegranskat)
    Abstract [en]

    This article provides an overview of current European Commission effort in term of educational innovation to reduce the gap between research and industry which still is a barrier to the economic development. Entrepreneurial innovation & education driving Europe's digital transformation (EIT Digital for short) is an European-based initiative fostering I&E (innovation and entrepreneurship) by integrating education, research and business at different educational levels. For instance in EIT master programmes, students work together with industries and academics to have a faster go-to-market of research results. Summer schools are part of the master programs; three of them have been organised related to CPS (cyber-physical systems), critical infrastructure and, more recently, Industry 4.0. Past and present events are discussed and the experience from these events is reported. It is further analysed how the general setup of the summer school program is affecting the educational aspects and achievement of the intended learning outcomes.

  • 155.
    Carholt, Cristoffer
    et al.
    Luleå University of Technology.
    Nikolakopoulos, George
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Fresk, Emil
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Andrikopoulos, Georgios
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Design, Modelling and Control of a Single Rotor UAV2016Ingår i: 24th Mediterranean Conference on Control and Automation,: June 21-24, Athens, Greece, 2016, Piscataway, NJ: Institute of Electrical and Electronics Engineers (IEEE), 2016, s. 840-845, artikel-id 7536015Konferensbidrag (Refereegranskat)
    Abstract [en]

    In this article, a novel Vertical Take-Off and Landing (VTOL) Single Rotor Unmanned Aerial Vehicle (SR- UAV) will be presented. The SRUAV’s design properties will be analysed in detail, with respect to technical novelties outlining the merits of such a conceptual approach. The system’s model will be mathematically formulated, while a cascaded P-PI and PID-based control structure will be utilized in extensive simulation trials for the preliminary evaluation of the SR-UAV’s attitude and translational performance.

  • 156.
    Carli, Ruggero
    et al.
    Department of Information Engineering, University of Padova.
    Notarstefano, Giuseppe
    Department of Engineering for Innovation, University of Salento.
    Schenato, Luca
    Department of Information Engineering, University of Padova.
    Varagnolo, Damiano
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Analysis of Newton-Raphson consensus for multi-agent convex optimization under asynchronous and lossy communications2015Ingår i: IEEE 54th Annual Conference on Decision and Control (CDC): Osaka, Japan, 15-18 Dec. 2015, Piscataway, NJ: IEEE Communications Society, 2015, s. 418-424, artikel-id 7402236Konferensbidrag (Refereegranskat)
    Abstract [en]

    We extend a multi-agent convex-optimization algorithm named Newton-Raphson consensus to a network scenario that involves directed, asynchronous and lossy communications. We theoretically analyze the stability and performance of the algorithm and, in particular, provide sufficient conditions that guarantee local exponential convergence of the node-states to the global centralized minimizer even in presence of packet losses. Finally, we complement the theoretical analysis with numerical simulations that compare the performance of the Newton-Raphson consensus against asynchronous implementations of distributed subgradient methods on real datasets extracted from open-source databases

  • 157.
    Carli, Ruggero
    et al.
    Department of Information Engineering, University of Padova.
    Notarstefano, Giuseppe
    Department of Engineering for Innovation, University of Salento.
    Schenato, Luca
    Department of Information Engineering, University of Padova.
    Varagnolo, Damiano
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Distributed quadratic programming under Asynchronous and Lossy Communications via Newton-Raphson Consensus2015Ingår i: 2015 European Control Conference (ECC): Linz, 15-17 July 2015, Piscataway, NJ: IEEE Communications Society, 2015, s. 2514-2520Konferensbidrag (Refereegranskat)
    Abstract [en]

    Quadratic optimization problems appear in several interesting estimation, learning and control tasks. To solve these problems in peer-to-peer networks it is necessary to design distributed optimization algorithms supporting directed, asynchronous and unreliable communication. This paper addresses this requirement by extending a promising distributed convex optimization algorithm, known as Newton-Raphson consensus, and originally designed for static and undirected communication. Specifically, we modify this algorithm so that it can cope with asynchronous, broadcast and unreliable lossy links, and prove that the optimization strategy correctly converge to the global optimum when the local cost functions are quadratic. We then support the intuition that this robustified algorithm converges to the true optimum also for general convex problems with dedicated numerical simulations.

  • 158.
    Carlson, Johan
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Birk, Wolfgang
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Martinsson, Pär-Erik
    Löfqvist, Torbjörn
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Håkansson, Mikael
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Castano, Miguel
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Linder, Tomas
    Projekt: SCOPE Norra2011Övrigt (Övrig (populärvetenskap, debatt, mm))
    Abstract [sv]

    SCOPE Norra är ett samarbetskonsortium för forskning och utveckling tillsammans med massa- och pappersindustrin i Norrbotten och Västerbotten. Projektet koordineras av centrumbildningen ProcessIT Innovations.Inom SCOPE Norra pågår ett flertal delprojekt, uppdelat på ett antal fokusområden.Huvudfinansiär för konsortiet är Tillväxtverket genom medel från EU:s strukturfonder.

  • 159.
    Castano, Miguel
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Birk, Wolfgang
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    A new approach to the dynamic RGA analysis of uncertain systems2008Ingår i: 2008 IEEE International Symposium on Computer-Aided Control System Design: [CACSD] ; San Antonio, TX, 3 - 5 September 2008, Piscataway, NJ: IEEE Communications Society, 2008, s. 365-370Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper deals with DRGA analysis for uncertain systems. Uncertainties in a process model can be translated into uncertainties in the DRGA which might invalidate the decision on the variable paring in decentralized control. Bounds for the uncertainties in the DRGA of a multivariable process are derived for a given nominal process model with known uncertainty region. The resulting uncertainty region for the DRGA is used to assess the validity of decisions based on the nominal DRGA. The methodology for the computation of the bounds is currently restricted to the 2-by-2 case. Beside an explanatory example, a case study on a coal injection vessel is conducted and discussed.

  • 160.
    Castano, Miguel
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Birk, Wolfgang
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Bounds on a gramian-based interaction measure for robust control structure selection2011Ingår i: 2011 9th IEEE International Conference on Control and Automation (ICCA 2011): Santiago, Chile, 19 - 21 December 2011, Piscataway, NJ: IEEE Communications Society, 2011, s. 88-93Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper reviews a method for approximating the bounds on a gramian-based Interaction Measure (IM) for systems described by uncertain parametric models. The considered IM is the Participation Matrix. The reviewed method is based on analyzing the uncertainty in the area enclosed by the Nyquist curve. Conditions for the exactitude of this method are derived, and implementation issues are discussed.

  • 161.
    Castano, Miguel
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Birk, Wolfgang
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Model based and empirical approaches to robust control structure selection based on the H2-norm2012Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper presents a method for the robust control structure selection based on the assessment of the H2-norm. For both uncertain parametric models and non parametric estimated frequency response functions (FRF) with confidence regions, the magnitude of the Bode diagram is analyzed and regions for the H2-norm are derived. The H2-norm has been successfully used to identify the significant input-output interconnections in multivariable system for the nominal case. The derived regions for the H2-norm of the interconnections are used to extent the H2-norm based method to the uncertain case, and enables robust control structure selection. The method is applied to theoretical examples and a quadruple tank setup to shows its feasibility.

  • 162.
    Castano, Miguel
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Birk, Wolfgang
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    New methods for interaction analysis of complex processes using weighted graphs2012Ingår i: Journal of Process Control, ISSN 0959-1524, E-ISSN 1873-2771, Vol. 22, nr 1, s. 280-295Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The selection of the structure of a controller in large scale industry processes usually requires extensive process knowledge. The aim of this paper is to report new results on recently suggested methods for the analysis of complex processes. These methods aid the designers in comprehending a process by representing structural and functional relationships from actuators and process disturbances to measured or estimated variables. The methods are formulated in a flexible framework based on graph theory, which can also be used for closed-loop analysis. Additionally, the sensitivity of the methods to scaling and time delays are discussed and resolved. It is also proposed how filtering can be used to restrict the analysis to a frequency region of interest. The feasibility of the methods is shown by the use of three case studies. A quadruple tank process is used to exemplify the methods and their use. Then the methods are applied on a real-life process, the stock preparation plant of a pulp and paper mill. The third study case analyzes a previously published example in closed loop. It is shown that the methods can be used to take efficient decisions on decentralized and sparse control structures, as well as assessing the channel interactions in a closed-loop system.

  • 163.
    Castano, Miguel
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Birk, Wolfgang
    Luleå tekniska universitet, Institutionen för system- och rymdteknik.
    New methods for structural and functional analysis of complex processes2009Ingår i: IEEE International Conference on Control Applications: St. Petersburg, Russia, 8 - 10 July 2009, Piscataway, NJ: IEEE Communications Society, 2009, s. 487-494Konferensbidrag (Refereegranskat)
    Abstract [en]

    The selection of the structure of a controller in large scale industry processes requires extensive process knowledge. The aim of this paper is to present methods which help designers to comprehend a process by representing structural and functional relationships from actuators and process disturbances to measured or estimated variables. This paper describes similarities between brain connectivity theory and interaction analysis in multivariable processes. Results from both theories are combined to create new methods for the analysis of industry processes. The developed methods are applied to an illustrative example.

  • 164.
    Castano, Miguel
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Birk, Wolfgang
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Asplund, Petter
    Optimation AB.
    Control configuration selection for integrating processes using graphs2015Ingår i: 2015 IEEE International Conference on Control Applications (CCA 2015): Sydney, Australia, September 21-23, Piscataway, NJ: IEEE Communications Society, 2015, s. 1606-1611, artikel-id 7320839Konferensbidrag (Refereegranskat)
    Abstract [en]

    Recently, methods for Control Configuration Selection (CCS) using weighted graphs have been introduced. These methods were integrated in a software tool which allows systematic CCS in industry processes by choosing a simplified model with a reduced structure on which control will be based. This paper addresses the extension of these graph-based methods to be applied to integrating systems, which often appear in industry processes, e.g. at storage vessels. The extension is based on restricting the analysis to a set of frequencies of interest which omits the infinite DC-gain. The results are validated and illustrated using a real-life case, namely the secondary heating system of a pulp & paper mill.

  • 165.
    Castano, Miguel
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Birk, Wolfgang
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Halvarsson, Björn
    Empirical approach to robust gramian-based analysis of process interactions in control structure selection2012Ingår i: 2011 50th IEEE Conference on Decision and Control and European Control Conference (CDC-ECC), Piscataway, NJ: IEEE Communications Society, 2012, s. 6210-6215Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper deals with the estimation of a gramian-based interaction measure from logged process data, and thereby removing the need of creating parametric models prior to the selection of the significant input-output interconnections. Moreover, the resulting confidence regions of the estimates can be used to perform a robust control structure selection.

  • 166.
    Castaño Arranz, Miguel
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Kadhim, Ali
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    On Guided and Automatic Control Configuration Selection: Application on a Secondary Heating System2017Rapport (Övrigt vetenskapligt)
    Abstract [en]

    This technical report provides supplementary materialto the research paper entitled ”On Guided and AutomaticControl Configuration Selection”, presented at the ETFA 2017.In that paper, different Control Configuration Selection (CCS)tools are reviewed and integrated into guided and automaticCCS methodologies. The guided CCS is a heuristic step-by-stepmethodology to be applied by practitioners, while the automaticCCS methodologies target the adaptation of such heuristicsinto algorithms which can be run in a computer and assist thepractitioners in the decision making. This report summarizesthe results of applying the introduced methodologies to a reallifeprocess: the Secondary Heating System. For an introductorybackground, preliminaries, and details on the methodologies,the reader is referred to the original research paper.

  • 167.
    Castaño Arranz, Miguel
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Birk, Wolfgang
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    On the selection of control configurations for uncertain systems using gramian-based Interaction Measures2016Ingår i: Journal of Process Control, ISSN 0959-1524, E-ISSN 1873-2771, Vol. 47, s. 213-225Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    critical step in the control design of industrial processes is the Control Configuration Selection (CCS), where each actuator is associated with a set of measurements which will be used in the calculation of the control action.

    A possible solution to the CCS problem is given by the gramian-based Interaction Measures (IMs), which are derived from nominal process models. This paper introduces the derivation of uncertainty bounds for a gramian-based IM using models with uncertainty described in multiplicative form. An alternative to this model-based approach is presented, where uncertainty bounds are estimated from a tailored experiment.

    In addition, a procedure for robust CCS is introduced. This procedure integrates the calculated uncertainty bounds in the design of the control configuration.

  • 168.
    Castaño Arranz, Miguel
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Birk, Wolfgang
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Online Automatic and Robust Control Configuration Selection2017Ingår i: 2017 25th Mediterranean Conference on Control and Automation, MED 2017, Piscataway, NJ: IEEE, 2017, s. 1367-1372, artikel-id 7984309Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper presents a complete method for automatic and robust control configuration selection for linear systems which relies upon acquired process data under gaussian noise excitation.

    The selection of the configuration  is based on the estimation of the Interaction Measure named Participation Matrix. This estimation is derived with uncertainty bounds, which allows to  determine online whether the uncertainty is sufficiently low to derive a robust decision on the control configuration to be used or if the uncertainty should be reduced  by e.g. prolonging the experiment to obtain more data.

  • 169.
    Castaño Arranz, Miguel
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Birk, Wolfgang
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Prediction Error based Interaction Measure for Control Configuration Selection in Linear and Nonlinear Systems2017Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper introduces an interaction measure, which can be applied both to linear and non-linear systems. The measure is based on the prediction error of the structurally reduced model and is denoted Prediction Error Index Array (PEIA). The linear PEIA is constructed as an extension of previous results using the $\mathcal{H}_2$-norm. The non-linear PEIA is an extension for systems represented by a model in the form of Volterra series. Additionally, the paper gives an interpretation of both linear and nonlinear PEIA as the fraction of the power of the output signal which is expressed by the reduced model resulting from  the  control configuration selection. Several examples are used to illustrate and compare the interaction measure with established methodologies, like the relative gain array, participation matrix, and Hankel Interaction Index array.

  • 170.
    Castaño Arranz, Miguel
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Birk, Wolfgang
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Kadhim, Ali
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    On Guided and Automatic Control Configuration Selection2018Ingår i: IEEE International Conference on Emerging Technologies and Factory Automation (ETFA), Piscataway, Nj: Institute of Electrical and Electronics Engineers (IEEE), 2018, Vol. F134116Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper discusses the guided and automatic control configuration selection in large scale complex systems. Due to the trend of increasesd level of automation and connectedness which is promoted by the Industry 4.0 strategy and supported by technologies relating to cyber-physical systems and the industrial internet of things, selecting appropriate control strategies becomes increasingly important and complex. This is especially important as a control strategies will limit the achievable performance of the process system, and there are  trade-offs between complexity of the control strategies, achievable performance, vulnerability and maintainability.

    The paper reviews the state of the art of methodologies that support the practitioners in taking decisions on control strategies, where two main approaches are considered, the guided one and a fully automatic one. It is shown how both approached can be conducted and examples are used to clarify the selection process.

  • 171.
    Castaño Arranz, Miguel
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Birk, Wolfgang
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Nikolakopoulos, George
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    A Survey on Control Configuration Selection and New Challenges in Relation to Wireless Sensor and Actuator Networks2017Ingår i: IFAC-PapersOnLine, ISSN 1045-0823, E-ISSN 1797-318X, Vol. 50, nr 1, s. 8810-8825Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This survey on Control Configuration Selection (CCS) includes methods based on relative gains, gramian-based interaction measures, methods based on optimization schemes, plantwide control, and methods for the reconfiguration of control systems. The CCS problem is discussed, and a set of desirable properties of a CCS method are defined. Open questions and research tracks are discussed, with the focus on new challenges in relation to the emerging area of Wireless Sensors and Actuator Networks.

  • 172.
    Castaño, Miguel
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Birk, Wolfgang
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Estimation of Gramian-Based Interaction Measures for Weakly Nonlinear Systems2015Ingår i: 2015 European Control Conference (ECC): Linz, 15-17 July 2015, Piscataway, NJ: IEEE Communications Society, 2015, s. 2438-2443Konferensbidrag (Refereegranskat)
    Abstract [en]

    A critical step in the control design of industrial processes is the Control Configuration Selection (CCS), where each actuator is grouped with a set of measurements to be used in the computation of its control action.Tools for CCS include gramian-based Interaction Measures (IMs), initially defined for linear systems. Since a trending research topic is the derivation of IMs for non-linear systems, a decision of the designer is therefore the approach to the problem in the linear or non-linear framework. For this end, a method is discussed that determines the degree of nonlinearity of a system based on a specially tailored experiment, and thus enables the selection of the correct framework for the analysis. The novelty is in the estimation of two gramian-based IMs with confidence bounds from the tailored experiment which is applicable if the process is revealed to be weakly non-linear. If the process is found to be strongly non-linear, then alternative approaches for the interaction analysis have to be considered.

  • 173.
    Castaño, Miguel
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Birk, Wolfgang
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Asplund, Petter
    Optimation AB.
    Rönnberg, Johan Karlsson
    K Algorithm Design.
    Systematic Control Configuration Selection of Secondary Heating Systems: A Case Study2014Konferensbidrag (Övrigt vetenskapligt)
  • 174.
    Castaño, Miguel
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Birk, Wolfgang
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Asplund, Petter
    Optimation AB.
    Rönnberg, Johan Karlsson
    K Algorithm Design.
    Systematic Control Configuration Selection of Secondary Heating Systems: A Case Study2014Konferensbidrag (Övrigt vetenskapligt)
  • 175.
    Chohan, Neha
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Rymdteknik.
    Robust trajectory planning of autonomous vehicles at intersections with communication impairments2019Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    In this thesis, we consider the trajectory planning of an autonomous vehicle to cross an intersection within a given time interval. The vehicle communicates its sensordata to a central coordinator which then computes the trajectory for the given time horizon and sends it back to the vehicle. We consider a realistic scenario in which the communication links are unreliable, the evolution of the state has noise (e.g., due to the model simplification and environmental disturbances), and the observationis noisy (e.g., due to noisy sensing and/or delayed information). The intersection crossing is modeled as a chance constraint problem and the stochastic noise evolution is restricted by a terminal constraint. The communication impairments are modeled as packet drop probabilities and Kalman estimation techniques are used for predicting the states in the presence of state and observation noises. A robust sub-optimalsolution is obtained using convex optimization methods which ensures that the intersection is crossed by the vehicle in the given time interval with very low chance of failure.

  • 176.
    Coelingh, Erik
    et al.
    Volvo, Göteborg.
    Lind, Henrik
    Volvo, Göteborg.
    Birk, Wolfgang
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Distner, Martin
    Volvo, Göteborg.
    Wetterberg, Daniel
    Volvo, Göteborg.
    Collision warning with auto brake2006Ingår i: FISITA 2006 World Automotive Congress, JSAE , 2006Konferensbidrag (Refereegranskat)
  • 177.
    Dadhich, Siddharth
    et al.
    Luleå tekniska universitet.
    Birk, Wolfgang
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Analysis and control of an extended Quadruple tank process2014Ingår i: 2014 European Control Conference (ECC), June 24-27, 2014. Strasbourg, France, Piscataway, NJ: IEEE Communications Society, 2014, s. 838-843, artikel-id 6862290Konferensbidrag (Refereegranskat)
    Abstract [en]

    An extension to the standard Quadruple tank process is proposed and analyzed. It is shown that the extended setup provides an improved platform for experimental and educational studies of MIMO control systems. Based on dynamic models for the process a control configuration selection is performed and both decentralized and decoupling control schemes are designed and tested. Moreover sparse IMC controllers have been evaluated against a decentralized control scheme for improvement in the stochastic performance. It is shown how a performance assessment method based on the FCOR algorithm can be used to find the optimal tuning of the IMC controller. It can be concluded that the proposed extension to the quadruple tank process is useful for benchmark and educational purposes.

  • 178.
    Dadhich, Siddharth
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Bodin, Ulf
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Sandin, Fredrik
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Andersson, Ulf
    Machine Learning approach to Automatic Bucket Loading2016Ingår i: 24th Mediterranean Conference on Control and Automation (MED): June 21-24, Athens, Greece, 2016, Piscataway, NJ: IEEE Communications Society, 2016, s. 1260-1265, artikel-id 7535925Konferensbidrag (Refereegranskat)
    Abstract [en]

    The automation of bucket loading for repetitive tasks of earth-moving operations is desired in several applications at mining sites, quarries and construction sites where larger amounts of gravel and fragmented rock are to be moved. In load and carry cycles the average bucket weight is the dominating performance parameter, while fuel efficiency and loading time also come into play with short loading cycles. This paper presents the analysis of data recorded during loading of different types of gravel piles with a Volvo L110G wheel loader. Regression models of lift and tilt actions are fitted to the behavior of an expert driver for a gravel pile. We present linear regression models for lift and tilt action that explain most of the variance in the recorded data and outline a learning approach for solving the automatic bucket loading problem. A general solution should provide good performance in terms of average bucket weight, cycle time of loading and fuel efficiency for different types of material and pile geometries. We propose that a reinforcement learning approach can be used to further refine models fitted to the behavior of expert drivers, and we briefly discuss the scooping problem in terms of a Markov decision process and possible value functions and policy iteration schemes.

  • 179.
    Daerga, Per-Anders
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Sundquist, Jan
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Material testing with Regula: demonstration and verification1991Rapport (Övrigt vetenskapligt)
  • 180.
    Delshad, Saleh Sayyad
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Gustafsson, Thomas
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Nonlinear observer design for a class of Lipschitz time-delay systems with unknown inputs: LMI approach2011Ingår i: Proceedings of the XXIII International Symposium on Information, Communication and Automation Technologies. (ICAT-2011), Piscataway, NJ: IEEE Communications Society, 2011Konferensbidrag (Refereegranskat)
    Abstract [en]

    In this paper, we consider a method to design a full-order nonlinear observer for a class of nonlinear time-delay systems with unknown inputs. Based on Lyapunov-Krasovskii functional, we derive a sufficient condition for existence of the designed observer which requires solving a set of nonlinear matrix inequalities. Then, the achieved condition is formulated in terms of two linear matrix inequalities (LMIs). Finally, the proposed observer is illustrated with an example.

  • 181. Ding, Limei
    On modeling and control of complex dynamic systems2000Licentiatavhandling, monografi (Övrigt vetenskapligt)
    Abstract [en]

    Nonlinear complex multi-input multi-output process is very troublesome to control. It is usually also ill-modeled. The problem of such process both in control and modeling requires a comprehensive utilization of various techniques. The thesis presents the methods for the modeling and control of complex systems. A typical example of complex processes is mineral flotation that characterized by multivariable, nonlinearities, strong interactions, stochastic disturbances, and large and variable delay times. The dynamic nonlinear model of a inverse continuous flotation process is developed based on the first order kinetics. The complexity of mineral flotation in modeling and control is shown by the analysis of the dynamic model and the relation between the process inputs and the process parameters. As an attractive alternative of conventional control technologies, fuzzy logic control is discussed for the control of an MIMO nonlinear flotation system and the simulation of the control system is carried out. LQG optimal control of the pulp level, a subsystem in a flotation process is studied and the robustness is analyzed based on the structured singular value. The control of infinite dimensional systems is known to all a knotty problem. Orthogonal collocation method, which is one of the methods of weighted residual, is employed to reduce the infinite dimensional model of the systems. In a case study a time delay system is approximated using the orthogonal collocation and a robust controller of the delay system is synthesized based on the method introduced by Glover and McFarlane in 1989. The robustness degradation caused by model reduction is discussed. The results show that the strategies studied in the thesis are available to solve the relevant modeling and control problems of complex systems.

  • 182. Ding, Limei
    et al.
    Gustafsson, Thomas
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Control of a delay system using robust finite-dimensional controller2001Ingår i: CSEE '2001: Conference Proceedings, Luleå tekniska universitet, 2001Konferensbidrag (Övrigt vetenskapligt)
  • 183. Ding, Limei
    et al.
    Gustafsson, Thomas
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Dynamic modeling of flotation circuits2000Ingår i: Elsevier IFAC Publications / IFAC Proceedings series, ISSN 1474-6670, s. 197-202Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The modeling of flotation is a difficult task due to the influences of mineralogical features of ores, floatability of various minerals governed by pulp environments, flotation kinetics and hydrodynamic variables. In the paper the dynamic modeling of flotation is studied. Based on the first order flotation rate equation, the dynamic description of a continuous flotation process is obtained both for a single continuous flotation cell and n cells arranged in series. A dynamic model for the multi-component case of continuous flotation is also discussed. The models obtained give the dynamic behaviors when the flotation parameters are changed due to the variation of the chemical and physical environment

  • 184. Ding, Limei
    et al.
    Gustafsson, Thomas
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Dynamic modeling of flotation circuits2000Ingår i: Future Trends in Automation in Mineral and Metal Processing: a proceedings volume from the IFAC workshop / MM 2000, Finland, 22-24 August 2000 / [ed] Sirkka-Liisa Jämsä-Jounela, Kidlington: Pergamon Press, 2000, s. 197-202Konferensbidrag (Refereegranskat)
    Abstract [en]

    The modeling of flotation is a difficult task due to the influences of mineralogical features of ores, floatability of various minerals governed by pulp environments, flotation kinetics and hydrodynamic variables. In the paper the dynamic modeling of flotation is studied. Based on the first order flotation rate equation, the dynamic description of a continuous flotation process is obtained both for a single continuous flotation cell and n cells arranged in series. A dynamic model for the mUlti-component case of continuous flotation is also discussed. The models obtained give the dynamic behaviors when the flotation parameters are changed due to the variation of the chemical and physical environment.

  • 185. Ding, Limei
    et al.
    Gustafsson, Thomas
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Modelling and control of a flotation process1999Ingår i: Control and optimization in minerals, metals and materials processing: proceedings of the International Symposium on Control and Optimization in Minerals, Metals and Materials Processing ; [part of the] 38th Annual Conference of Metallurgist of CIM, 38e Conférence Annuelle des Métallurgistes de l'ICM - [theme:] gateway to the 21st century - Aux portes du 21e siècle, August 22 - 26 Août, 1999, Québec City, Québec, Canada / [ed] D. Hodouin; C. Bazin; A. Desbiens, Montreal: MetSoc , 1999, s. 285-298Konferensbidrag (Refereegranskat)
    Abstract [en]

    A general description of a flotation process is given. The dynamic model of a MIMO nonlinear subprocess in flotation, i.e. the pulp levels in five compartments in series is developed and the model is verified with real data from a production plant. In order to reject constant disturbances five extra states are introduced and the model is modified. An exact linearization has been made for the non-linear model and a linear quadratic Gaussian controller is proposed based on the linearized model. The simulation result shows an improved performance of the pulp level control when the set points are changed or a disturbance occur. In future the controller will be tested in production

  • 186. Ding, Limei
    et al.
    Gustafsson, Thomas
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Robustness of a pulp level control system2000Ingår i: Reglermöte: preprints, Uppsala, 2000Konferensbidrag (Övrigt vetenskapligt)
  • 187. Ding, Limei
    et al.
    Gustafsson, Thomas
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Johansson, Andreas
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Model identification of a nonlinear subprocess in a continuous paper pulp digester2006Ingår i: Measurement and control - applications for the operator: Control Systems 2006, June 6-8, 2006, Tampere Finland / [ed] Risto Ritala, Finnish Society of Automation , 2006Konferensbidrag (Refereegranskat)
  • 188. Ding, Limei
    et al.
    Gustafsson, Thomas
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Johansson, Andreas
    Model parameter estimation of simplified linear models for a continuous paper pulp digester2007Ingår i: Journal of Process Control, ISSN 0959-1524, E-ISSN 1873-2771, Vol. 17, nr 2, s. 115-127Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A physical model of a continuous paper pulp digester is simplified and two subprocesses selected from the digester are modelled by coupled linear partial differential equations. This study focuses on the parameter identification of the simplified linear models. Finite-dimensional approximation of the model is made and a software package developed for identification of distributed parameter processes is applied. This identification system is developed for flexibility to allow identification for different choices of subprocesses and process variables. Unknown parameters of the subprocess models are estimated and the results are illustrated by process simulation and model validation.

  • 189. Ding, Limei
    et al.
    Gustafsson, Thomas
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Johansson, Andreas
    Physical model parameter estimation of a nonlinear process2007Ingår i: Proceedings of the 2006 IEEE International Conference on Control Applications Applications: Munich, Germany, 4 - 6 October 2006, Piscataway, NJ: IEEE Communications Society, 2007, s. 2933-2938Konferensbidrag (Refereegranskat)
    Abstract [en]

    A physical model of a nonlinear subprocess in a continuous paper pulp digester is discussed and simplified. Model approximation is carried out in order to produce a simple linear model to be used for unknown parameter estimation of the physical model. The Taylor series expansion and the orthogonal collocation method are applied for the model linearization and model lumping, respectively. The reduced model is expressed as a standard state space form. The model parameters are estimated in the least squares sense, and the parameters retain their own physical meanings. The results of the parameter estimation are discussed and the model is verified using validation data.

  • 190. Ding, Limei
    et al.
    Gustafsson, Thomas
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Su, F
    Luleå tekniska universitet.
    Fuzzy logic control of flotation process1998Ingår i: Reglermöte '98: preprints, Lund: Reglerteknik, Lunds tekniska högskola , 1998Konferensbidrag (Övrigt vetenskapligt)
  • 191. Ding, Limei
    et al.
    Gustafsson, Thomas
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Su, Fenwei
    Luleå tekniska universitet.
    Application of fuzzy control to a flotation process1999Ingår i: Proceedings of the 14th World Congress: International Federation of Automatic Control : Beijing, P.R. China, 5 - 9 July 1999 / [ed] Han-Fu Chen, Kildington: Publ. for the International Federation of Automatic Control by Pergamon, , 1999, s. 391-396Konferensbidrag (Refereegranskat)
    Abstract [en]

    The application of fuzzy logic in the control of flotation is studied in this paper. A general description of apatite flotation process is given and a dynamic model is developed. A fuzzy logic controller is proposed for a nonlinear isolated continuous flotation process. The knowledge base of the controller is constructed on the basis of the semi-batch results from the apatite flotation experiments and available knowledge sources. The design of the controller does not need an exact process model. The simulation result shows that the fuzzy logic controller can reduce collector dosage consumption of the apatite flotation process while maintaining the phosphorous content in magnetite concentrate within an acceptable limits less than 0.025% P. Stability of the fuzzy control system is discussed

  • 192. Ding, Limei
    et al.
    Gustafsson, Thomas
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Su, Fenwei
    Luleå tekniska universitet.
    Application of fuzzy control to a flotation process1999Ingår i: Elsevier IFAC Publications / IFAC Proceedings series, ISSN 1474-6670, Vol. 32, nr 2, s. 6998-7003Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The application of fuzzy logic in the control of flotation is studied in this paper. A general description of apatite flotation process is given and a dynamic model is developed. A fuzzy logic controller is proposed for a nonlinear isolated continuous flotation process. The knowledge base of the controller is constructed on the basis of the semi-batch results from the apatite flotation experiments and available knowledge sources. The design of the controller does not need an exact process model. The simulation result shows that the fuzzy logic controller can reduce collector dosage consumption of the apatite flotation process while maintaining the phosphorous content in magnetite concentrate within an acceptable limits less than 0.025% P. Stability of the fuzzy control system is discussed

  • 193. Ding, Limei
    et al.
    Johansson, Andreas
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Gustafsson, Thomas
    Application of reduced models for robust control and state estimation of a distributed parameter system2009Ingår i: Journal of Process Control, ISSN 0959-1524, E-ISSN 1873-2771, Vol. 19, nr 3, s. 539-549Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper studies the application of reduced models of a distributed parameter system for robust process control and state estimation. We take the approach of integrating model reduction, parameter identification, and model uncertainty analysis, in purpose to find an appropriate trade-off between complexity and robust performance. The application example is the temperature system in a continuous paper pulp digester. Physical modeling of this process results in coupled linearized partial differential equations which are then reduced into low-order nominal process models using an orthogonal collocation approximation method.Two different approaches to obtaining a model uncertainty description are adapted for use on a distributed parameter system with low-order nominal model and shown to produce similar results when tested with measurement data. It is also demonstrated how this uncertainty description, in combination with the reduced model, may be used for robust control design and verification of the control performance on the distributed parameter system.Finally, the possibility of estimating the distributed process state using a state observer for the reduced process is demonstrated. Measurements of the process state in a certain position is available and is shown to agree with the estimated state at the same position.

  • 194.
    Dudarenko, Natalia
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Ushakov, A.
    Department of Control Systems and Informatics, National Research University of Information Technologies Mechanics and Optics.
    Numerical operability analysis of multidimensional systems with interval parameters using interval degeneration factors2010Ingår i: Proceedings of the WSEAS international conferences, Corfu Island, Greece, July 22 - 25, 2010: WSEAS International Conference on SYSTEMS / [ed] Nikos E. Mastorakis, Athen: WSEAS Press , 2010, Vol. 1, s. 422-426Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper deals with the problem of numerical analysis of multidimensional systems with interval parameters in relation to the operability of MIMO systems. The problem is analyzed for the case when the relative estimation of the interval parameters exceeds 0.5 and based on the assumption that only the state matrix of a MIMO system contains interval parameters. The problem of operability estimation of the MIMO system is solved with interval degeneration factors. Interval degeneration factors are constructed using interval arithmetic and the singular values of the interval criterion matrices of the system. An operability analysis algorithm of multidimensional systems with interval parameters is proposed in the paper. The results are supported with an example

  • 195.
    Duffie, N.
    et al.
    University of Wisconsin.
    Bollinger, J.
    University of Wisconsin.
    Schmidtbauer, Bengt
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Development of a Menu-Driven Programmable System of Machinery Drives1983Ingår i: CIRP annals, ISSN 0007-8506, E-ISSN 1726-0604, Vol. 32, nr 1, s. 281-285Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In many industrial applications of machinery drives, there is need for controlling two or more drive elements with various speed and or position relationships maintained between drives. Drive motors may incorporate a wide variety of feedback transducers and have command signals derived from programmable sources or other drives in the system. This paper describes the development of a generalized system which incorporates a variety of sensors and allows a machinery designer to establish master/slave relationships to suit requirements for particular applications. The software system supporting the configurable drive allows a particular system configuration to be determined through presentation of a menu to an operator who selects the number of drives, appropriate sensors and inter-drive relationships dictated by the machine specifications. Individual drives are configured by selecting either a speed or a position feedback sensor and the source of commands for that drive. Commands for a given drive can be determined as a ratio of either the command input or the measured output of another drive as well as an operator programmable drive profile. The paper presents a summary of the control philosophy, detailed algorithms for establishing a variety of drive configurations, and techniques used to achieve the various features of the configurable drive including velocity ratioing, position phase control, and program indexing of one drive relative to another. The software package developed includes a diagnostic system for identifying and observing dynamic performances

  • 196.
    Ebadat, Afrooz
    et al.
    School of Electrical Engineering, KTH Royal Institute of Technology, ACCESS and the Department of Automatic Control, School of Electrical Engineering, KTH Royal Institute of Technology.
    Bottegal, Giulio
    School of Electrical Engineering, KTH Royal Institute of Technology, ACCESS and the Department of Automatic Control, School of Electrical Engineering, KTH Royal Institute of Technology.
    Molinari, Marco
    Kungliga tekniska högskolan, KTH, ACCESS and the Department of Automatic Control, School of Electrical Engineering, KTH Royal Institute of Technology.
    Wahlberg, Bo
    School of Electrical Engineering, KTH Royal Institute of Technology, ACCESS and the Department of Automatic Control, School of Electrical Engineering, KTH Royal Institute of Technology.
    Varagnolo, Damiano
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Hjalmarsson, Håkan
    School of Electrical Engineering, KTH Royal Institute of Technology, ACCESS and the Department of Automatic Control, School of Electrical Engineering, KTH Royal Institute of Technology.
    Johansson, Karl Henrik
    School of Electrical Engineering, KTH Royal Institute of Technology, ACCESS and the Department of Automatic Control, School of Electrical Engineering, KTH Royal Institute of Technology.
    Multi-room occupancy estimation through adaptive gray-box models2015Ingår i: IEEE 54th Annual Conference on Decision and Control (CDC): Osaka, Japan, 15-18 Dec. 2015, Piscataway, NJ: IEEE Communications Society, 2015, s. 3705-3711, artikel-id 7402794Konferensbidrag (Refereegranskat)
    Abstract [en]

    We consider the problem of estimating the occupancy level in buildings using indirect information such as CO2 concentrations and ventilation levels. We assume that one of the rooms is temporarily equipped with a device measuring the occupancy. Using the collected data, we identify a gray-box model whose parameters carry information about the structural characteristics of the room. Exploiting the knowledge of the same type of structural characteristics of the other rooms in the building, we adjust the gray-box model to capture the CO2 dynamics of the other rooms. Then the occupancy estimators are designed using a regularized deconvolution approach which aims at estimating the occupancy pattern that best explains the observed CO2 dynamics. We evaluate the proposed scheme through extensive simulation using a commercial software tool, IDA-ICE, for dynamic building simulation

  • 197.
    Ebadat, Afrooz
    et al.
    School of Electrical Engineering, KTH Royal Institute of Technology.
    Bottegal, Giulio
    School of Electrical Engineering, KTH Royal Institute of Technology.
    Varagnolo, Damiano
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Wahlberg, Bo
    School of Electrical Engineering, KTH Royal Institute of Technology.
    Hjalmarsson, Håkan
    School of Electrical Engineering, KTH Royal Institute of Technology.
    Johansson, Karl Henrik
    School of Electrical Engineering, KTH Royal Institute of Technology.
    Blind identification strategies for room occupancy estimation2015Ingår i: 2015 European Control Conference (ECC): Linz, 15-17 July 2015, Piscataway, NJ: IEEE Communications Society, 2015, s. 1315-1320, artikel-id 7330720Konferensbidrag (Refereegranskat)
    Abstract [en]

    We propose and test on real data a two-tier estimation strategy for inferring occupancy levels from measurements of CO2 concentration and temperature levels. The first tier is a blind identification step, based either on a frequentist Maximum Likelihood method, implemented using non-linear optimization, or on a Bayesian marginal likelihood method, implemented using a dedicated Expectation-Maximization algorithm. The second tier resolves the ambiguity of the unknown multiplicative factor, and returns the final estimate of the occupancy levels. The overall procedure addresses some practical issues of existing occupancy estimation strategies. More specifically, first it does not require the installation of special hardware, since it uses measurements that are typically available in many buildings. Second, it does not require apriori knowledge on the physical parameters of the building, since it performs system identification steps. Third, it does not require pilot data containing measured real occupancy patterns (i.e., physically counting people for some periods, a typically expensive and time consuming step), since the identification steps are blind.

  • 198.
    Ebadat, Afrooz
    et al.
    School of Electrical Engineering, KTH Royal Institute of Technology.
    Bottegal, Giulio
    School of Electrical Engineering, KTH Royal Institute of Technology.
    Varagnolo, Damiano
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Wahlberg, Bo
    School of Electrical Engineering, KTH Royal Institute of Technology.
    Johansson, Karl H.
    Kungliga tekniska högskolan, KTH.
    Regularized Deconvolution-Based Approaches for Estimating Room Occupancies2015Ingår i: IEEE Transactions on Automation Science and Engineering, ISSN 1545-5955, E-ISSN 1558-3783, Vol. 12, nr 4, s. 1157-1168Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We address the problem of estimating the number of people in a room using information available in standard HVAC systems. We propose an estimation scheme based on two phases. In the first phase, we assume the availability of pilot data and identify a model for the dynamic relations occurring between occupancy levels, CO2 concentration and room temperature. In the second phase, we make use of the identified model to formulate the occupancy estimation task as a deconvolution problem. In particular, we aim at obtaining an estimated occupancy pattern by trading off between adherence to the current measurements and regularity of the pattern. To achieve this goal, we employ a special instance of the so-called fused lasso estimator, which promotes piecewise constant estimates by including an l(1) norm-dependent term in the associated cost function. We extend the proposed estimator to include different sources of information, such as actuation of the ventilation system and door opening/closing events. We also provide conditions under which the occupancy estimator provides correct estimates within a guaranteed probability. We test the estimator running experiments on a real testbed, in order to compare it with other occupancy estimation techniques and assess the value of having additional information sources

  • 199.
    Ebadat, Afrooz
    et al.
    ACCESS and the Department of Automatic Control, School of Electrical Engineering, KTH Royal Institute of Technology, Sweden.
    Varagnolo, Damiano
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Bottegal, G
    TU Eindhoven, Department of Electrical Engineering, Eindhoven, The Netherlands.
    Wahlberg, Bo
    ACCESS and the Department of Automatic Control, School of Electrical Engineering, KTH Royal Institute of Technology, Sweden.
    Johansson, K. H.
    ACCESS and the Department of Automatic Control, School of Electrical Engineering, KTH Royal Institute of Technology, Sweden.
    Application-oriented input design for room occupancy estimation algorithms2018Ingår i: 2017 IEEE 56th Conference on Decision and Control, CDC, Piscataway, NJ: Institute of Electrical and Electronics Engineers (IEEE), 2018, s. 3417-3424Konferensbidrag (Refereegranskat)
    Abstract [en]

    We consider the problem of occupancy estimation in buildings using available environmental information. In particular, we study the problem of how to collect data that is informative enough for occupancy estimation purposes. We thus propose an application-oriented input design approach for designing the ventilation signal to be used while collecting the system identification datasets. The main goal of the method is to guarantee a certain accuracy in the estimated occupancy levels while minimizing the experimental time and effort. To take into account potential limitations on the actuation signals we moreover formulate the problem as a recursive nonlinear and nonconvex optimization problem, solved then using exhaustive search methods. We finally corroborate the theoretical findings with some numerical examples, which results show that computing ventilation signals using experiment design concepts leads to occupancy estimator performing 4 times better in terms of Mean Square Error (MSE).

  • 200.
    Edgar Alexander, Montero Vera
    Luleå tekniska universitet, Institutionen för system- och rymdteknik.
    Virtual Commissioning of an industrialwood cutter machine: A software in the loop simulation2020Självständigt arbete på grundnivå (kandidatexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    The methods used today for the commissioning and validation of industrial machines requires theconstruction of physical prototypes. Those prototypes help the engineers to e.g. validate if theprogram code meant to control a machine works as intended. In recent years the development ofnew techniques for the commissioning and validation of industrial machines has changed rapidlythanks to the development of new software. The method used in this thesis is called simulationin the loop. Another method that can be benecial to use is hardware in the loop. Using thosemethods for the commissioning of a machine is called virtual commissioning. The simulation inthe loop method is used to simulate both the machine and the control system that operate thatmachine. This is called a digital twin, a virtual copy of the physical hardware and its control systemthat can be used without the need for a real prototype to be available.The software used in this thesis comes all from the company Siemens and those are TIA Portal,Mechatronics Concept Designer, SIMIT and PLCSim Advanced. By using those programs it waspossible to build a digital twin with rigid body dynamics and its control system of the industrialmodel that was given by the company Renholmen AB. This model contained all the necessarycomponents needed for a virtual commissioning project to be done without the need to be at thefactory oor.The results showed that it was possible to achieve a real time simulation, allowing the possibilityto trim the controller parameters without the need of a physical prototype. Design errors were alsofound thanks to the results of the simulation.This new technique has shown to be a useful tool due to most of the work could be done on a digitalmodel of the machine. Simulations can reduce the time to market for industrial machines and alsohelp engineers to validate and optimize the product at an early stage. This tool that can be usedto validate industrial machines before they are created.

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