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  • 251. Nordh, Jerker
    et al.
    Wigren, Torbjörn
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för systemteknik. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Reglerteknik.
    Schön, Thomas B.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för systemteknik. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Reglerteknik.
    Bernhardsson, Bo
    Particle filtering based identification for autonomous nonlinear ODE models2015Inngår i: Proc. 17th IFAC Symposium on System Identification, International Federation of Automatic Control , 2015, s. 415-420Konferansepaper (Fagfellevurdert)
  • 252.
    Nordsjö, Anders E.
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Reglerteknik.
    Ninness, Brett M.
    Wigren, Torbjörn
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Reglerteknik.
    Quantifying model errors caused by nonlinear undermodeling in linear system identification1996Konferansepaper (Fagfellevurdert)
  • 253.
    Nordsjö, Anders E.
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Reglerteknik.
    Ninness, Brett M.
    Wigren, Torbjörn
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Reglerteknik.
    Quantifying model errors caused by nonlinear undermodeling in linear system identification1995Rapport (Annet vitenskapelig)
  • 254. Nordsjö, Anders E.
    et al.
    Wigren, Torbjörn
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för systemteknik. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Reglerteknik.
    On estimation of errors caused by non-linear undermodelling in system identification2002Inngår i: International Journal of Control, ISSN 0020-7179, E-ISSN 1366-5820, Vol. 75, nr 14, s. 1100-1113Artikkel i tidsskrift (Fagfellevurdert)
  • 255.
    Nordström, Peter
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för systemteknik.
    Multi-objective optimization and Pareto navigation for voyage planning2014Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    The shipping industry is very large and ships require a substantial amount of fuel. However, fuel consumption is not the only concern. Time of arrival, safety concerns, distance travelled etc. are also of importance and these objectives might be inherently conflicting.

    This thesis aims to demonstrate multi-objective optimization and Pareto navigation for application in voyage planning.

    In order to perform this optimization, models of weather, ocean conditions, ship dynamics and propulsion system are needed. Statistical methods for estimation of resistance experienced in calm and rough sea are used. An earlier developed framework is adopted to perform the optimization and Pareto navigation.

    The results show that it is a suitable approach in voyage planning. A strength of the interactive Pareto navigation is the overview of the solution space presented to the decision maker and the control of the spread of the objective space. Another benefit is the possibilities of assigning specific values on objectives and setting thresholds in order to narrow down the solution space. The numerical results reinforces the trend of slow steaming to decrease fuel consumption.

  • 256.
    Norgren, Tommy
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Signaler och System.
    Styrud, Jonathan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Signaler och System.
    Non-periodic sampling schemes for control applications2010Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    In recent years, research in the field of automation has been advancing quickly in the direction of wireless networks of sensors and actuators. This development has introduced a need to reduce the amount of communication. A number of different alternative schemes have been proposed. They are usually divided into event-triggered schemes and self-triggered ones.

    The main purpose of this Master's thesis was to further develop and evaluate the sesampling schemes, focusing on their needed communication. The effect on control performance by the different schemes was also taken into account. Because of the difficulty in performing a theoretical comparison, the thesis focused on evaluating the schemes in simulations and in experiments on real industrial processes.

    The results indicate that simply using a slower periodic scheme may reduce as much communication without losing much performance as the more flexible schemes. This would imply that investing further into the other schemes may be of waste. However, using an event-triggered scheme with improvements introduced in this report may offer some advantages when it comes to performance and simplicity in setup. Maybe more importantly, it is safer during rapidly changing conditions, which also makes it very unlikely that a slow periodic sampler would ever be implemented on a real system. The results in general are very positive with communication reductions of over 90% when using a well tuned base sampling interval and over 99% when the comparison is made to current implementations in the industry, all without significant loss of performance.

  • 257.
    Norlander, Hans
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för systemteknik. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Reglerteknik.
    Model accuracy for active damping of a viscoelastic beam2014Inngår i: Preprints of the 19th World Congress, 2014, s. 4511-4516Konferansepaper (Fagfellevurdert)
  • 258.
    Norlander, Hans
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för systemteknik. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Reglerteknik.
    Modelling and Control Methods with Applications to Mechanical Waves2014Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Models, modelling and control design play important parts in automatic control. The contributions in this thesis concern topics in all three of these concepts.

    The poles are of fundamental importance when analyzing the behaviour of a system, and pole placement is an intuitive and natural approach for control design. A novel parameterization for state feedback gains for pole placement in the linear multiple input case is presented and analyzed. It is shown that when the open and closed loop poles are disjunct, every state feedback gain can be parameterized. Other properties are also investigated.

    Hammerstein models have a static non-linearity on the input. A method for exact compensation of such non-linearities, combined with introduction of integral action, is presented. Instead of inversion of the non-linearity the method utilizes differentiation, which in many cases is simpler.

    A partial differential equation (PDE) can be regarded as an infinite order model. Many model based control design techniques, like linear quadratic Gaussian control (LQG), require finite order models. Active damping of vibrations in a viscoelastic beam, modelled as a PDE, is considered. The beam is actuated by piezoelectric elements and its movements are measured by strain gauges. LQG design is used, for which different finite order models, approximating the PDE model, are constructed. The so obtained controllers are evaluated on the original PDE model. Minimization of the measured strain yields a satisfactory performance, but minimization of transversal deflection does not. The effect of the model accuracy of the finite order model approximations is also investigated. It turns out that a model with higher accuracy in a specified frequency interval gives controllers with better performance.

    The wave equation is another PDE. A PDE model, with one spatial dimension, is established. It describes wave propagation in a tube perforated with helical slots. The model describes waves of both extensional and torsional type, as well as the coupling between the two wave types. Experimental data are used for estimation of model parameters, and for assessment of the proposed model in two different cases. The model is found adequate when certain geometrical assumptions are valid.

    Delarbeid
    1. Parameterization of state feedback gains for pole assignment
    Åpne denne publikasjonen i ny fane eller vindu >>Parameterization of state feedback gains for pole assignment
    2001 (engelsk)Licentiatavhandling, monografi (Annet vitenskapelig)
    Abstract [en]

    The pole assignment problem has been subject for research for a long time. For single-input single-output systems this problem is well understood but for multi-input multi-output systems the pole assignment problem is more complex.

    In this thesis a parameterization of state feedback gains for pole assignment is characterized with respect to completeness, redundancy and existence. In order to make a systematic examination of this parameterization a number of classes are introduced.

    This parameterization depends on two matrices that can be regarded as design parameters. In the thesis it is shown how the degree of freedom in the pole assignment problem for multi-input systems is characterized by these two matrices.

    It turns out that the properties of the parameterization depends on whether the characteristic polynomials of the open and the closed loop systems are coprime or not. It is shown in the thesis that if the characteristic polynomials are coprime, every possible feedback gain can be parameterized in this way, and in this sense the parameterization is complete. If the characteristic polynomials have factors in common the parameterization is not complete. In the thesis the shortcomings of the parameterization for this case are characterized.

    The design parameters seem to offer a greater degree of freedom than what can be offered in the pole assignment problem. This indicates a certain degree of overparameterization. This redundancy in the design parameters is characterized in the thesis.

    The parameterization implies that a certain matrix is invertible. Necessary conditions for when this matrix is invertible are given in terms of the two design parameters. It is shown that this matrix is invertible for almost every value of the design parameters when the characteristic polynomials are coprime, and hence that the parameterized gains are generally applicable.

    The parameterization and its properties are illustrated on a linear model of the military aircraft JAS Gripen.

    sted, utgiver, år, opplag, sider
    Uppsala University, 2001
    Serie
    IT licentiate theses / Uppsala University, Department of Information Technology, ISSN 1404-5117 ; 2001-007
    HSV kategori
    Forskningsprogram
    Reglerteknik
    Identifikatorer
    urn:nbn:se:uu:diva-86017 (URN)
    Veileder
    Tilgjengelig fra: 2001-05-20 Laget: 2005-05-05 Sist oppdatert: 2017-08-31bibliografisk kontrollert
    2. An integrating linearization method for Hammerstein models
    Åpne denne publikasjonen i ny fane eller vindu >>An integrating linearization method for Hammerstein models
    2005 (engelsk)Inngår i: Automatica, ISSN 0005-1098, Vol. 41, nr 10, s. 1825-1828Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    This paper considers a method for linearization of models containing

    static input nonlinearities in series with a linear model, so called

    Hammerstein models. The method linearizes the system exactly, and is

    performed by differentiating the nonlinearity

    with respect to the input signal. Using this approach, an integration

    is added in the loop gain of the linearized system via the internal

    feedback. The method presented here is an equivalent alternative

    to the standard method that utilizes the

    inverse of the static nonlinearity complemented with an

    integration. Particularly, in cases when

    analytic inversion is

    difficult, the presented method provides an attractive alternative.

    Emneord
    Linearization; Hammerstein models; Static nonlinearities; Actuator nonlinearity control;
    HSV kategori
    Identifikatorer
    urn:nbn:se:uu:diva-74724 (URN)
    Tilgjengelig fra: 2005-11-07 Laget: 2005-11-07 Sist oppdatert: 2015-01-23
    3. Modeling and control of a viscoelastic piezolaminated beam
    Åpne denne publikasjonen i ny fane eller vindu >>Modeling and control of a viscoelastic piezolaminated beam
    2005 (engelsk)Inngår i: Proc. IFAC 16th World Congress, 2005Konferansepaper, Publicerat paper (Fagfellevurdert)
    Identifikatorer
    urn:nbn:se:uu:diva-71411 (URN)
    Tilgjengelig fra: 2005-05-06 Laget: 2005-05-06 Sist oppdatert: 2015-01-23
    4. On the impact of model accuracy for active damping of a viscoelastic beam
    Åpne denne publikasjonen i ny fane eller vindu >>On the impact of model accuracy for active damping of a viscoelastic beam
    2011 (engelsk)Rapport (Annet vitenskapelig)
    Abstract [en]

    How much do model errors influence the closed loop performance? This question is investigated for the control problem of designing active damping of vibrations in a viscoelastic cantilever beam. The beam is physically modeled using Fourier transformed Euler-Bernoulli beam equations. For control design the standard LQG technique is employed, and two different finite order models are used. One is based on truncated modal analysis of the system, and the other model is numerically fitted with respect to the frequency response of the physically theoretical model. The so obtained controllers are evaluated on the physical model with respect to disturbance attenuation and robustness for stability. It is found that all controllers stabilizes the system and attenuates the vibrations, but the controllers based on the numerically fitted model perform notably better than those based on truncated modal analysis.

    Serie
    Technical report / Department of Information Technology, Uppsala University, ISSN 1404-3203 ; 2011-013
    HSV kategori
    Forskningsprogram
    Elektroteknik med inriktning mot reglerteknik
    Identifikatorer
    urn:nbn:se:uu:diva-229593 (URN)
    Tilgjengelig fra: 2014-08-21 Laget: 2014-08-11 Sist oppdatert: 2015-01-23
    5. Parameter estimation from wave propagation tests on a tube perforated by helical slots
    Åpne denne publikasjonen i ny fane eller vindu >>Parameter estimation from wave propagation tests on a tube perforated by helical slots
    2013 (engelsk)Inngår i: Mechanical systems and signal processing, ISSN 0888-3270, E-ISSN 1096-1216, Vol. 40, nr 1, s. 385-399Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    For a tube with doubly symmetric cross section and perforations by helical slots there is a coupling between extension and torsion. In this paper a one dimensional (1D) model structure for a tube with such a helical slot segment (HSS) is established, and parameters accounting for the coupling between extension and torsion are estimated from wave propagation experiments. In these experiments incident extensional waves were generated through axial impact by strikers of different lengths, causing reflected and transmitted waves of extensional and torsional type which were measured in terms of surface strains on either side of the HSS part of the tube. A statistical test on the experimental data shows that the output residuals (the difference between modeled and experimental output) cannot be explained by measurement noise alone. This is not surprising since the 1D model structure is based on some simplifying assumptions concerning the geometry of the HSS. Parameters for two different geometries of the HSS are estimated, and the models are assessed in terms of model fa, simulations and wave energy distribution. It turns out that for one case, where the geometrical assumptions are valid, the 1D model is adequate, while for another case, where the validity of the assumptions is questionable, it is not. It is concluded that the 1D model structure provides a simple and efficient description of the HSS if the geometrical assumptions are valid.

    Emneord
    Tube, Helical slots, Elastic wave, Extension, Torsion, Parameter estimation
    HSV kategori
    Forskningsprogram
    Teknisk fysik med inriktning mot tillämpad mekanik
    Identifikatorer
    urn:nbn:se:uu:diva-208351 (URN)10.1016/j.ymssp.2013.04.011 (DOI)000323803100024 ()
    Tilgjengelig fra: 2013-10-01 Laget: 2013-09-30 Sist oppdatert: 2017-12-06bibliografisk kontrollert
  • 259.
    Norlander, Hans
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för systemteknik. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Reglerteknik.
    On the impact of model accuracy for active damping of a viscoelastic beam2011Rapport (Annet vitenskapelig)
    Abstract [en]

    How much do model errors influence the closed loop performance? This question is investigated for the control problem of designing active damping of vibrations in a viscoelastic cantilever beam. The beam is physically modeled using Fourier transformed Euler-Bernoulli beam equations. For control design the standard LQG technique is employed, and two different finite order models are used. One is based on truncated modal analysis of the system, and the other model is numerically fitted with respect to the frequency response of the physically theoretical model. The so obtained controllers are evaluated on the physical model with respect to disturbance attenuation and robustness for stability. It is found that all controllers stabilizes the system and attenuates the vibrations, but the controllers based on the numerically fitted model perform notably better than those based on truncated modal analysis.

  • 260.
    Norlander, Hans
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för systemteknik. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Reglerteknik.
    Parameterization of state feedback gains for pole assignment2001Licentiatavhandling, monografi (Annet vitenskapelig)
    Abstract [en]

    The pole assignment problem has been subject for research for a long time. For single-input single-output systems this problem is well understood but for multi-input multi-output systems the pole assignment problem is more complex.

    In this thesis a parameterization of state feedback gains for pole assignment is characterized with respect to completeness, redundancy and existence. In order to make a systematic examination of this parameterization a number of classes are introduced.

    This parameterization depends on two matrices that can be regarded as design parameters. In the thesis it is shown how the degree of freedom in the pole assignment problem for multi-input systems is characterized by these two matrices.

    It turns out that the properties of the parameterization depends on whether the characteristic polynomials of the open and the closed loop systems are coprime or not. It is shown in the thesis that if the characteristic polynomials are coprime, every possible feedback gain can be parameterized in this way, and in this sense the parameterization is complete. If the characteristic polynomials have factors in common the parameterization is not complete. In the thesis the shortcomings of the parameterization for this case are characterized.

    The design parameters seem to offer a greater degree of freedom than what can be offered in the pole assignment problem. This indicates a certain degree of overparameterization. This redundancy in the design parameters is characterized in the thesis.

    The parameterization implies that a certain matrix is invertible. Necessary conditions for when this matrix is invertible are given in terms of the two design parameters. It is shown that this matrix is invertible for almost every value of the design parameters when the characteristic polynomials are coprime, and hence that the parameterized gains are generally applicable.

    The parameterization and its properties are illustrated on a linear model of the military aircraft JAS Gripen.

  • 261.
    Norlander, Hans
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Reglerteknik. AUTOMATIC CONTROL.
    Parameterization of state feedback gains for pole placement2003Inngår i: Proceedings, European Control Conference 2003, Cambridge, UK, 2003Konferansepaper (Fagfellevurdert)
  • 262.
    Norlander, Hans
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för systemteknik. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Reglerteknik.
    Valdek, Urmas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad mekanik.
    Lundberg, Bengt
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad mekanik.
    Söderström, Torsten
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för systemteknik. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Reglerteknik.
    Parameter estimation from wave propagation tests on a tube perforated by helical slots2013Inngår i: Mechanical systems and signal processing, ISSN 0888-3270, E-ISSN 1096-1216, Vol. 40, nr 1, s. 385-399Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    For a tube with doubly symmetric cross section and perforations by helical slots there is a coupling between extension and torsion. In this paper a one dimensional (1D) model structure for a tube with such a helical slot segment (HSS) is established, and parameters accounting for the coupling between extension and torsion are estimated from wave propagation experiments. In these experiments incident extensional waves were generated through axial impact by strikers of different lengths, causing reflected and transmitted waves of extensional and torsional type which were measured in terms of surface strains on either side of the HSS part of the tube. A statistical test on the experimental data shows that the output residuals (the difference between modeled and experimental output) cannot be explained by measurement noise alone. This is not surprising since the 1D model structure is based on some simplifying assumptions concerning the geometry of the HSS. Parameters for two different geometries of the HSS are estimated, and the models are assessed in terms of model fa, simulations and wave energy distribution. It turns out that for one case, where the geometrical assumptions are valid, the 1D model is adequate, while for another case, where the validity of the assumptions is questionable, it is not. It is concluded that the 1D model structure provides a simple and efficient description of the HSS if the geometrical assumptions are valid.

  • 263.
    Nygren, Johannes
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Reglerteknik. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för systemteknik.
    Input-Output Stability Analysis of Networked Control Systems2016Doktoravhandling, monografi (Annet vitenskapelig)
    Abstract [en]

    The main focus of the thesis is to derive stability criteria for networked control system (NCS) models featuring imperfections such as time-varying and constant delays, quantization, packet dropouts, and non-uniform sampling intervals. The main method of proof is based on matrix algebra, as opposed to methods using Lyapunov functions or integral quadratic constraints (IQC). This work puts a particular focus on handling systems with a single integrator. This framework is elaborated in different specific directions as motivated by practical realizations of NCSs, as well as through numerical examples. A novel proof of the discrete time multivariate circle criterion and the Tsypkin criterion for systems including a single integrator is presented, as well as a stability criterion for linear systems with a single integrator subject to variable sampling periods and sector-bounded nonlinear feedback. Four stability criteria for different classes of systems subject to packet loss and time-varying delay are given. Stability criteria for a closed loop system switching between a set of linear time-invariant systems (LTIs) are proved. This result is applied to a single-link NCS with feedback subject to packet loss. Finally, necessary and sufficient conditions for delay-independent stability of an LTI system subject to nonlinear feedback are derived.

  • 264.
    Nygren, Johannes
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för systemteknik. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Reglerteknik.
    Output feedback control: Some methods and applications2014Licentiatavhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    This thesis studies some output feedback control laws. Particularly, iterative learning control (ILC) and decentralized network based algorithms are studied. Applications to control of wastewater treatment plants are outlined. For a linear, discrete time MIMO plant, it is shown that the size of the global controller gain, also referred to as the diffusion matrix, plays an important role in stabilization of a decentralized control system with possibly non-linear output feedback. Based on information from a step response experiment of the open loop system, a controller gain which is sufficient for stability can be found. For the SISO case, frequency response expressions are derived for the choice of this controller gain. The results relate nicely to notions of optimality and the Nyquist stability criterion. Various types of ILC algorithms are analysed and numerically illustrated. In particular, new expressions of the asymptotic control error variance for adjoint based iterative learning control (ILC) are derived. It is proven that the control error variance converges to its minimum if a decreasing learning gain matrix is used for ILC. In a simulation study ILC is applied to control a sequencing batch reactor. It is shown numerically that an adjoint based ILC outperforms inverse based ILC and model-free, proportional ILC. A merge of an activated sludge process simulator and a simulator for a wireless sensor network is described and used for illustrating some control performance. Finally, in a numerical optimization study it is shown that the aeration energy can be decreased if many dissolved oxygen sensors are used for aeration control in a biological reactor for nitrogen removal. This results may support future use of inexpensive wireless sensor networks for control of wastewater treatment plants.

    Delarbeid
    1. A cooperative decentralized PI control strategy: discrete-time analysis and nonlinear feedback
    Åpne denne publikasjonen i ny fane eller vindu >>A cooperative decentralized PI control strategy: discrete-time analysis and nonlinear feedback
    2012 (engelsk)Inngår i: Proc. 3rd IFAC Workshop on Distributed Estimation and Control in Networked Systems, 2012, s. 103-108Konferansepaper, Publicerat paper (Fagfellevurdert)
    Abstract [en]

    This paper discusses an extension of a PI control strategy towards the control of a large m×m-MIMO system. This strategy is fully decentralized, it requires only the tuning of m different controllers, while we only allow for neighboring controllers to exchange error signals. This makes it a strong candidate for an implementation on a decentralized, low-power and high performance Wireless Sensor Network (WSN). The main idea is to feed locally observed control errors (’feedback’) not only into the local control law, but also in a fixed proportionate way into neighboring controllers. The analysis concerns convergence to a set point. The analysis is essentially based on a conversion of the PI control law into a discrete-time gradient descent scheme. As an interesting byproduct, this analysis indicates how to deal with quantization functions and nonlinear effects in the feedback signals.

    HSV kategori
    Identifikatorer
    urn:nbn:se:uu:diva-183475 (URN)
    Konferanse
    NecSys 2012, September 14-15, Santa Barbara, CA
    Prosjekter
    ProFuN
    Tilgjengelig fra: 2012-10-31 Laget: 2012-10-26 Sist oppdatert: 2014-06-12bibliografisk kontrollert
    2. On the stability and optimality of an output feedback control law
    Åpne denne publikasjonen i ny fane eller vindu >>On the stability and optimality of an output feedback control law
    2014 (engelsk)Manuskript (preprint) (Annet vitenskapelig)
    HSV kategori
    Identifikatorer
    urn:nbn:se:uu:diva-226178 (URN)
    Prosjekter
    ProFuN
    Tilgjengelig fra: 2014-06-12 Laget: 2014-06-12 Sist oppdatert: 2019-07-03bibliografisk kontrollert
    3. Approximate adjoint-based iterative learning control
    Åpne denne publikasjonen i ny fane eller vindu >>Approximate adjoint-based iterative learning control
    2014 (engelsk)Inngår i: International Journal of Control, ISSN 0020-7179, E-ISSN 1366-5820, Vol. 87, nr 5, s. 1028-1046Artikkel i tidsskrift (Fagfellevurdert) Published
    HSV kategori
    Identifikatorer
    urn:nbn:se:uu:diva-210604 (URN)10.1080/00207179.2013.865144 (DOI)000332199500012 ()
    Prosjekter
    ProFuN
    Forskningsfinansiär
    Swedish Foundation for Strategic Research , RIT08-0065
    Tilgjengelig fra: 2013-12-20 Laget: 2013-11-11 Sist oppdatert: 2017-12-06bibliografisk kontrollert
    4. Benchmark simulation model no. 1 with a wireless sensor network for monitoring and control
    Åpne denne publikasjonen i ny fane eller vindu >>Benchmark simulation model no. 1 with a wireless sensor network for monitoring and control
    2011 (engelsk)Rapport (Annet vitenskapelig)
    Serie
    Technical report / Department of Information Technology, Uppsala University, ISSN 1404-3203 ; 2011-002
    HSV kategori
    Identifikatorer
    urn:nbn:se:uu:diva-171577 (URN)
    Prosjekter
    ProFuN
    Tilgjengelig fra: 2011-01-21 Laget: 2012-03-22 Sist oppdatert: 2014-06-12bibliografisk kontrollert
  • 265.
    Nygren, Johannes
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för systemteknik. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Reglerteknik.
    Carlsson, Bengt
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för systemteknik. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Reglerteknik.
    Benchmark simulation model no. 1 with a wireless sensor network for monitoring and control2011Rapport (Annet vitenskapelig)
  • 266.
    Nygren, Johannes
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för systemteknik. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Reglerteknik.
    Carlsson, Bengt
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för systemteknik. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Reglerteknik.
    Benchmark simulation model no. 1 with a wireless sensor network for monitoring and control2011Konferansepaper (Annet vitenskapelig)
  • 267.
    Nygren, Johannes
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för systemteknik. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Reglerteknik.
    Pelckmans, Kristiaan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för systemteknik. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Reglerteknik.
    A closed loop stability condition of switched systems applied to NCSs with packet loss2015Inngår i: Proc. 5th IFAC Workshop on Distributed Estimation and Control in Networked Systems, International Federation of Automatic Control , 2015Konferansepaper (Fagfellevurdert)
  • 268.
    Nygren, Johannes
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för systemteknik. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Reglerteknik.
    Pelckmans, Kristiaan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för systemteknik. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Reglerteknik.
    A cooperative decentralized PI control strategy: discrete-time analysis and nonlinear feedback2012Inngår i: Proc. 3rd IFAC Workshop on Distributed Estimation and Control in Networked Systems, 2012, s. 103-108Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper discusses an extension of a PI control strategy towards the control of a large m×m-MIMO system. This strategy is fully decentralized, it requires only the tuning of m different controllers, while we only allow for neighboring controllers to exchange error signals. This makes it a strong candidate for an implementation on a decentralized, low-power and high performance Wireless Sensor Network (WSN). The main idea is to feed locally observed control errors (’feedback’) not only into the local control law, but also in a fixed proportionate way into neighboring controllers. The analysis concerns convergence to a set point. The analysis is essentially based on a conversion of the PI control law into a discrete-time gradient descent scheme. As an interesting byproduct, this analysis indicates how to deal with quantization functions and nonlinear effects in the feedback signals.

  • 269.
    Nygren, Johannes
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för systemteknik. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Reglerteknik.
    Pelckmans, Kristiaan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för systemteknik. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Reglerteknik.
    A direct proof of the discrete-time multivariate circle and Tsypkin criteria2016Inngår i: IEEE Transactions on Automatic Control, ISSN 0018-9286, E-ISSN 1558-2523, Vol. 61, nr 2, s. 544-549Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This technical note presents a new proof of the circle criterion for multivariate, discrete-time systems with time-varying feedback nonlinearities. A new proof for the multivariate Tsypkin criterion for time-invariant monotonic feedback nonlinearities is derived as well. Both integrator- and non-integrator systems are considered. The proofs are direct in the sense that they do not resort to any existing result in systems theory, such as Lyapunov theory, passivity theory or the small-gain theorem. Instead, the proofs refer to the asymptotic properties of block-Toeplitz matrices. One major advantage of the new proof is that it elegantly handles integrator systems without resorting to loop transformation/pole shifting techniques. Additionally, less conservative stability bounds are derived by making stronger assumptions on the sector bound conditions on the feedback nonlinearities. In particular, it is exemplified how this technique relaxes stability conditions of (i) a model predictive control (MPC) rule and (ii) an integrator system.

  • 270.
    Nygren, Johannes
    et al.
    Ericsson AB, Torshamnsgatan 23, S-16483 Stockholm, Sweden.
    Pelckmans, Kristiaan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Reglerteknik.
    A stability criterion for switching Lur'e systems with switching-path restrictions2018Inngår i: Automatica, ISSN 0005-1098, E-ISSN 1873-2836, Vol. 96, s. 337-341Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper derives a stability criterion for switching Lur'e MIMO systems with time-varying nonlinearities, where switching is subject to given restrictions. These restrictions are encoded via the notion of a switching path, interpolating the criterion between the single-system case and arbitrary switching. The criterion for switching Lur'e systems is shown to boil down to a familiar LMI criterion for linear switching systems for the case the Lur'e systems have a linear feedback. The model of a switching Lur'e system is used to describe an MPC control scheme subject to loss of output readings. This example illustrates the practical and theoretical usefulness of the introduced switching path restrictions.

  • 271.
    Nygren, Johannes
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för systemteknik. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Reglerteknik.
    Pelckmans, Kristiaan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för systemteknik. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Reglerteknik.
    Conditions for input-output stability of discrete-time Luré systems with time-varying delays2015Inngår i: Proc. 54th Conference on Decision and Control, Piscataway, NJ: IEEE , 2015, s. 7707-7714Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper derives a stability condition for a type of Lur'e systems with time-varying delays and a feedback nonlinearity. The case of discrete-time systems is considered, consisting of a LTI, fed back though a time-varying static nonlinearity. There is an additional delay before or after this nonlinearity, which delays the signals by a positive, time-varying number of steps. Either the time-delay needs to be bounded by a constant (if the LTI system contains a single integrator) or its rate need to be bounded (in case the LTI system is stable). It turns out that, if the LTI has a single integrator with non-decreasing impulse response, the derived stability criterion coincides exactly with the circle criterion for the corresponding constant delay system. The technical proofs rely on direct manipulation of the involved signals, and do not make use of traditional tools as the small gain theorem, Lyapunov functions or passivity results.

  • 272.
    Nygren, Johannes
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för systemteknik. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Reglerteknik.
    Pelckmans, Kristiaan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för systemteknik. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Reglerteknik.
    On the stability and optimality of an output feedback control law2014Manuskript (preprint) (Annet vitenskapelig)
  • 273.
    Nygren, Johannes
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för systemteknik. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Reglerteknik.
    Pelckmans, Kristiaan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för systemteknik. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Reglerteknik.
    Stability analysis of an adaptively sampled controller for SISO systems with nonlinear feedback2015Inngår i: Proc. American Control Conference: ACC 2015, American Automatic Control Council , 2015, s. 5353-5358Konferansepaper (Fagfellevurdert)
  • 274.
    Nygren, Johannes
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för systemteknik. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Reglerteknik.
    Pelckmans, Kristiaan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för systemteknik. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Reglerteknik.
    Carlsson, Bengt
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för systemteknik. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Reglerteknik.
    Approximate adjoint-based iterative learning control2014Inngår i: International Journal of Control, ISSN 0020-7179, E-ISSN 1366-5820, Vol. 87, nr 5, s. 1028-1046Artikkel i tidsskrift (Fagfellevurdert)
  • 275.
    Nygren, Johannes
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för systemteknik. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Reglerteknik.
    Pelckmans, Kristiaan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för systemteknik. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Reglerteknik.
    Carlsson, Bengt
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för systemteknik. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Reglerteknik.
    Iterative Learning Control and Recursive Identification2010Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    This abstract discusses our investigations relating Iterative Learning Control (ILC) for periodic systems on the one hand, and the class of Recursive Identification (RI), Gradient Descent (GD), Stochastic Approximation (SA) and adaptive filtering algorithms on the other. The benefit of such is the straightforward transfer of results in the latter context which is useful to study different design decisions made for the former. We discuss briefly the possible relevance of this observation for (i) design and analysis of suitable gain factors, (ii) working with constrained control signals, (iii) designing a model-free control strategy. For a survey of design, analysis and applications of ILC, see e.g. (1; 2). For an overview of practical and theoretical studies of RI and SA see (3), GD (4; 5), and adaptive filtering (6; 7). In this note we articulate the basic idea, and discuss further work which may be expected from this.

  • 276.
    Nygren, Johannes
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för systemteknik. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Reglerteknik.
    Wigren, Torbjörn
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för systemteknik. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Reglerteknik.
    Pelckmans, Kristiaan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för systemteknik. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Reglerteknik.
    Delay-independent stability criteria for networked control systems2015Rapport (Annet vitenskapelig)
  • 277.
    Nygren, Johannes
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för systemteknik. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Reglerteknik.
    Wigren, Torbjörn
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för systemteknik. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Reglerteknik.
    Pelckmans, Kristiaan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för systemteknik. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Reglerteknik.
    Frequency conditions for stable networked controllers with time-delay2019Inngår i: International Journal of Control, ISSN 0020-7179, E-ISSN 1366-5820, Vol. 92, nr 4, s. 886-895Artikkel i tidsskrift (Fagfellevurdert)
  • 278. Nájera, Silvano
    et al.
    Gil-Martínez, Montserrat
    Zambrano, Jesús A.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för systemteknik. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Reglerteknik.
    ATAD control goals through the analysis of process variables and evaluation of quality, production and cost2015Inngår i: Water Science and Technology, ISSN 0273-1223, E-ISSN 1996-9732, Vol. 71, nr 5, s. 717-724Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The aim of this paper is to establish and quantify different operational goals and control strategies in autothermal thermophilic aerobic digestion (ATAD). This technology appears as an alternative to conventional sludge digestion systems. During the batch-mode reaction, high temperatures promote sludge stabilization and pasteurization. The digester temperature is usually the only online, robust, measurable variable. The average temperature can be regulated by manipulating both the air injection and the sludge retention time. An improved performance of diverse biochemical variables can be achieved through proper manipulation of these inputs. However, a better quality of treated sludge usually implies major operating costs or a lower production rate. Thus, quality, production and cost indices are defined to quantify the outcomes of the treatment. Based on these, tradeoff control strategies are proposed and illustrated through some examples. This paper's results are relevant to guide plant operators, to design automatic control systems and to compare or evaluate the control performance on ATAD systems.

  • 279.
    Odelbrink, Camilla
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för systemteknik.
    Design of an Alternative Frequency Controller for Hydropower Stations: Reducing the 60-second Floating in the Grid Frequency of the Nordic Power System2014Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    A periodic oscillation in the grid frequency of the Nordic power system has been observed. The oscillations, also denoted as a floating, have periods of about 60 to 90 seconds. The reason for the floating is not fully known, and the strength of the floating has been increasing during the last years. It is assumed that the floating causes an undesired wear of the systems frequency control equipment.

    The aim of the study was to research the possibility of a new control structure in primary frequency controlling hydropower units. The purpose of the new modified control structure was to dampen the grid frequency floating. The modified design of the controller was conditioned to be implemented in a smaller fraction of all regulating hydropower stations in the Nordic power system. This smaller fraction has here been assumed to 10 %.

    The new structure of the modified controller was designed as a leadlag-filter, where a shape was assumed as to give the filter high energy in the frequency range of focus. The parameters of the leadlag-filter were determined according to a set of criteria, including damping ability, stability margins and preconditions on the control signals from the modified system.

    The study showed that a leadlag-filter could be constructed so that a periodic grid frequency floating with periods of 60-90 seconds would be significantly reduced in amplitude. The reduction of the floating did not necessarily require more generated power compared to the current system, though the modified plants did deliver most of the power. Both reduction of the amplitude of the floating and amount of required power depended on the amplitude and frequency of the disturbance causing the floating.

  • 280.
    Olsson, Claes
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för systemteknik. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Reglerteknik.
    Active Vibration Control of Multibody Systems: Application to Automotive Design2005Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Active vibration control to reduce vibrations and structure borne noise is considered using a powerful multi-disciplinary virtual design environment which enables control system design to be considered as an integral part of the overall vehicle design.

    The main application studied is active automotive engine vibration isolation where, first, the potential of large frequency band multi-input multi-output H2 feedback control is considered. Facilitated by the virtual environment, it is found necessary to take non-linear characteristics into account to achieve closed-loop stability.

    A physical explanation to why receiver structure flexibility insignificantly affect the open and closed-loop characteristics in case of total force feedback in contrast to acceleration feedback is then given. In this context, the inherent differences between model order reduction by modal and by balanced truncation are being stressed.

    Next, applying state-of-the-art algorithms for recursive parameter estimation, time-domain adaptive filtering is shown to lack sufficient tracking performance to deal with multiple spectral components of transient engine excitations corresponding to rapid car accelerations.

    Finally, plant non-linearity as well as transient excitation are successfully handled using narrow band control based on feedback of disturbance states estimates. To deal with the non-linear characteristics, an approach to generate linear parameter varying descriptions of non-linear systems is proposed. Parameter dependent quadratic stability is assessed using a derived affine closed-loop system representation.

    This thesis also considers actuator saturation induced limit cycles for observer-based state feedback control systems encountered when dealing with the active isolation application. It is stressed that the fundamental observer-based anti-windup technique could imply severely deteriorated closed-loop characteristics and even sustained oscillations. That is in the case when the observer is fed by the saturated control signal in contrast to the computed one. Based on piecewise affine system descriptions, analytical tools to conclude about limit cycles and exponential closed-loop stability are provided for the two observer implementations.

    Delarbeid
    1. Active Automotive Engine Vibration Isolation Using Feedback Control
    Åpne denne publikasjonen i ny fane eller vindu >>Active Automotive Engine Vibration Isolation Using Feedback Control
    Inngår i: Journal of Sound and VibrationArtikkel i tidsskrift (Fagfellevurdert) Submitted
    Identifikatorer
    urn:nbn:se:uu:diva-93126 (URN)
    Tilgjengelig fra: 2005-05-04 Laget: 2005-05-04bibliografisk kontrollert
    2. On Hazards of Using Fundamental Anti-windup Technique for H2 State-space Controllers With an Explicit Observer
    Åpne denne publikasjonen i ny fane eller vindu >>On Hazards of Using Fundamental Anti-windup Technique for H2 State-space Controllers With an Explicit Observer
    2003 Inngår i: Proceedings of the European Control Conference, Cambridge, UKArtikkel i tidsskrift (Fagfellevurdert) Published
    Identifikatorer
    urn:nbn:se:uu:diva-93127 (URN)
    Tilgjengelig fra: 2005-05-04 Laget: 2005-05-04bibliografisk kontrollert
    3. Saturation-induced Limit Cycles in Observer-based State Feedback Control
    Åpne denne publikasjonen i ny fane eller vindu >>Saturation-induced Limit Cycles in Observer-based State Feedback Control
    Inngår i: AutomaticaArtikkel i tidsskrift (Fagfellevurdert) Submitted
    Identifikatorer
    urn:nbn:se:uu:diva-93128 (URN)
    Tilgjengelig fra: 2005-05-04 Laget: 2005-05-04bibliografisk kontrollert
    4. Structure Flexibility Impacts on Robust Active Vibration Isolation Using Mixed Sensitivity Optimisation
    Åpne denne publikasjonen i ny fane eller vindu >>Structure Flexibility Impacts on Robust Active Vibration Isolation Using Mixed Sensitivity Optimisation
    2005 Inngår i: Technical Report, Department of Information Technology, Uppsala University, Number 2005-003, JanuaryArtikkel i tidsskrift (Fagfellevurdert) Published
    Identifikatorer
    urn:nbn:se:uu:diva-93129 (URN)
    Tilgjengelig fra: 2005-05-04 Laget: 2005-05-04bibliografisk kontrollert
    5. Comparative Study of Recursive Parameter Estimation Algorithms with Application to Active Vibration Isolation
    Åpne denne publikasjonen i ny fane eller vindu >>Comparative Study of Recursive Parameter Estimation Algorithms with Application to Active Vibration Isolation
    2004 Inngår i: Technical Report, Department of Information Technology, Uppsala University, Number 2004-051, NovemberArtikkel i tidsskrift (Fagfellevurdert) Published
    Identifikatorer
    urn:nbn:se:uu:diva-93130 (URN)
    Tilgjengelig fra: 2005-05-04 Laget: 2005-05-04bibliografisk kontrollert
    6. Disturbance Observer-Based Automotive Engine Vibration Isolation Dealing With Non-linear Dynamics and Transient Excitation
    Åpne denne publikasjonen i ny fane eller vindu >>Disturbance Observer-Based Automotive Engine Vibration Isolation Dealing With Non-linear Dynamics and Transient Excitation
    2005 Inngår i: Technical Report, Department of Information Technology, Uppsala University, Number 2005-009Artikkel i tidsskrift (Fagfellevurdert) Published
    Identifikatorer
    urn:nbn:se:uu:diva-93131 (URN)
    Tilgjengelig fra: 2005-05-04 Laget: 2005-05-04bibliografisk kontrollert
  • 281.
    Olsson, Fredrik
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för systemteknik. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Reglerteknik.
    Modeling and assessment of human balance and movement disorders using inertial sensors2018Licentiatavhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Inertial sensors and magnetometers are abundant in today's society, where they can be found in many of our everyday electronic devices, such as smart phones or smart watches. Their primary function is to measure the movement and orientation of the device and provide this information for the apps that request it.

    This licenciate thesis explores the use of these types of sensors in biomedical applications. Specifically, how these sensors can be used to analyze human movement and work as a tool for assessment of human balance and movement disorders. The methods presented in this thesis deal with mathematical modeling of the sensors, their relationship to the biomechanical models that are used to describe the dynamics of human movement and how we can combine these models to describe the mechanisms behind human balance and quantify the symptoms of movement disorders.

    The main contributions come in the form of four papers. A practical calibration method for accelerometers is presented in Paper I, that deals with compensation of intrinsic sensor errors that are common for relatively cheap sensors that are used in e.g. smart phones. In Paper II we present an experimental evaluation and minor extension of methods that are used to determine the position of the joints in the biomecanical model, using inertial sensor data alone. Paper III deals with system identification of nonlinear controllers operating in closed loop, which is a method that can be used to model the neuromuscular control mechanisms behind human balance. In Paper IV we propose a novel method for quantification of hand tremor, a primary symptom of neurological disorders such as Parkinson's disease (PD) or Essential tremor (ET), where we make use of data collected from sensors in a smart phone. The thesis also contains an introduction to the sensors, biomechanical modeling, neuromuscular control and the various estimation and modeling techniques that are used throughout the thesis.

    Delarbeid
    1. Accelerometer calibration using sensor fusion with a gyroscope
    Åpne denne publikasjonen i ny fane eller vindu >>Accelerometer calibration using sensor fusion with a gyroscope
    2016 (engelsk)Inngår i: Proc. 19th Statistical Signal Processing Workshop, Piscataway, NJ: IEEE, 2016, s. 660-664Konferansepaper, Publicerat paper (Fagfellevurdert)
    sted, utgiver, år, opplag, sider
    Piscataway, NJ: IEEE, 2016
    HSV kategori
    Identifikatorer
    urn:nbn:se:uu:diva-308761 (URN)10.1109/SSP.2016.7551836 (DOI)000390840200132 ()978-1-4673-7803-1 (ISBN)
    Konferanse
    SSP 2016, June 26–29, Palma de Mallorca, Spain
    Prosjekter
    CADICS
    Tilgjengelig fra: 2016-08-25 Laget: 2016-11-30 Sist oppdatert: 2018-05-14bibliografisk kontrollert
    2. Experimental evaluation of joint position estimation using inertial sensors
    Åpne denne publikasjonen i ny fane eller vindu >>Experimental evaluation of joint position estimation using inertial sensors
    2017 (engelsk)Inngår i: Proc. 20th International Conference on Information Fusion, Piscataway, NJ: IEEE, 2017, s. 354-361Konferansepaper, Publicerat paper (Fagfellevurdert)
    sted, utgiver, år, opplag, sider
    Piscataway, NJ: IEEE, 2017
    HSV kategori
    Identifikatorer
    urn:nbn:se:uu:diva-335035 (URN)10.23919/ICIF.2017.8009669 (DOI)000410938300052 ()978-0-9964-5270-0 (ISBN)
    Konferanse
    Fusion 2017, July 10–13, Xi'an, China
    Tilgjengelig fra: 2017-08-15 Laget: 2017-11-30 Sist oppdatert: 2018-05-14bibliografisk kontrollert
    3. Identification of nonlinear feedback mechanisms operating in closed loop using inertial sensors
    Åpne denne publikasjonen i ny fane eller vindu >>Identification of nonlinear feedback mechanisms operating in closed loop using inertial sensors
    2018 (engelsk)Konferansepaper, Publicerat paper (Fagfellevurdert)
    Abstract [en]

    In this paper we study the problem of identifying linear and nonlinear feedback mechanisms, or controllers, operating in closed loop. A recently developed identification method for nonlinear systems, the LAVA method, is used for this purpose. Identification data is obtained from inertial sensors, that provide information about the movement of the system, in the form of linear acceleration and angular velocity measurements. This information is different from the information that is available to the controller to be identified, which makes use of unknown internal sensors instead. We provide two examples, a simulated neuromuscular controller in standing human balance, and a lead-filter controlling a physical position servo using a DC motor. Both linear and nonlinear controllers are used in the examples. We show that the LAVA method is able to identify sparse, parsimonious models of the controllers.

    sted, utgiver, år, opplag, sider
    IFAC Papers Online, 2018
    Serie
    IFAC-PapersOnLine, ISSN 2405-8963 ; 51:15
    HSV kategori
    Identifikatorer
    urn:nbn:se:uu:diva-350607 (URN)10.1016/j.ifacol.2018.09.190 (DOI)000446599200081 ()
    Konferanse
    18th IFAC Symposium on System Identification (SYSID), Stockholm, Sweden, 9–11 July, 2018
    Forskningsfinansiär
    Swedish Research Council, 2015-05054
    Tilgjengelig fra: 2018-10-08 Laget: 2018-05-14 Sist oppdatert: 2018-12-11bibliografisk kontrollert
  • 282.
    Olsson, Fredrik
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för systemteknik. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Reglerteknik.
    Halvorsen, Kjartan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för systemteknik. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Reglerteknik.
    Experimental evaluation of joint position estimation using inertial sensors2017Inngår i: Proc. 20th International Conference on Information Fusion, Piscataway, NJ: IEEE, 2017, s. 354-361Konferansepaper (Fagfellevurdert)
  • 283.
    Olsson, Fredrik
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för systemteknik. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Reglerteknik.
    Halvorsen, Kjartan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för systemteknik. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Reglerteknik. Department of Mecatronics, Tecnológico de Monterrey, Mexico.
    Zachariah, Dave
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för systemteknik. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Reglerteknik.
    Mattsson, Per
    Department of Electronics, Mathematics and Natural Sciences, University of Gävle, Sweden.
    Identification of nonlinear feedback mechanisms operating in closed loop using inertial sensors2018Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In this paper we study the problem of identifying linear and nonlinear feedback mechanisms, or controllers, operating in closed loop. A recently developed identification method for nonlinear systems, the LAVA method, is used for this purpose. Identification data is obtained from inertial sensors, that provide information about the movement of the system, in the form of linear acceleration and angular velocity measurements. This information is different from the information that is available to the controller to be identified, which makes use of unknown internal sensors instead. We provide two examples, a simulated neuromuscular controller in standing human balance, and a lead-filter controlling a physical position servo using a DC motor. Both linear and nonlinear controllers are used in the examples. We show that the LAVA method is able to identify sparse, parsimonious models of the controllers.

  • 284.
    Olsson, Fredrik
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för systemteknik. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Reglerteknik.
    Medvedev, Alexander
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för systemteknik. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Reglerteknik.
    Tremor Severity Rating by Markov Chains2018Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The paper deals with mathematical modeling tools for tremor quantification, a problem arising in e.g. clinical applications and sports. Tremor is an involuntary repetitive movement of extremities, head, or trunk that occurs in disease but also in health, due to e.g. strain or fatigue. Quantification of tremor is traditionally performed by ocular observation, while numerous technologies based on wearable accelerometer data exist and have been tested in medical practice. The currently available approaches rely on spectral analysis that reduces a fundamentally nonlinear and non-stationary phenomenon to a linear combination of harmonic components. The classical nonlinear identification methods are as well of limited use because the underlying system is essentially autonomous and produces sustained oscillations without exogenous excitation. An alternative view on tremor is therefore adopted that treats the problem from a severity rating perspective aligned with clinical practices. The tremor amplitude is modelled by a Markov chain, where the states represent the predefined intervals of severity. A comparison with a previously developed event-based method of tremor quantification is provided on data collected using a smart phone in a patient diagnosed with Parkinson disease and undergoing Deep Brain Stimulation therapy. The experimental procedure is unobtrusive and can be implemented in a way that is transparent to the patient.

  • 285. Paridari, K.
    et al.
    Mady, A. E. -D
    La Porta, S.
    Chabukswar, R.
    Blanco, J.
    Teixeira, A.
    Sandberg, H.
    Boubekeur, M.
    Cyber-Physical-Security Framework for Building Energy Management System2016Inngår i: 2016 ACM/IEEE 7th Int. Conf. Cyber-Physical Syst. ICCPS 2016, 2016Konferansepaper (Fagfellevurdert)
    Abstract [en]

    © 2016 IEEE. Energy management systems (EMS) are used to control energy usage in buildings and campuses, by employing technologies such as supervisory control and data acquisition (SCADA) and building management systems (BMS), in order to provide reliable energy supply and maximise user comfort while minimising energy usage. Historically, EMS systems were installed when potential security threats were only physical. Nowadays, EMS systems are connected to the building network and as a result directly to the outside world. This extends the attack surface to potential sophisticated cyber-attacks, which adversely impact EMS operation, resulting in service interruption and downstream financial implications. Currently, the security systems that detect attacks operate independently to those which deploy resiliency policies and use very basic methods. We propose a novel EMS cyber-physical-security framework that executes a resilient policy whenever an attack is detected using security analytics. In this framework, both the resilient policy and the security analytics are driven by EMS data, where the physical correlations between the data-points are identified to detect outliers and then the control loop is closed using an estimated value in place of the outlier. The framework has been tested using a reduced order model of a real EMS site.

  • 286.
    Paz, Luis
    et al.
    Departamento de Matematica, Faculdade de Ciencias, Universidade do Porto, Porto, Portugal.
    Martins da Silva, Margarida
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för systemteknik. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Reglerteknik.
    Esteves, Simao
    Centro Hospitalar do Porto, Porto, Portugal.
    Mendonça, Teresa
    Departamento de Matematica, Faculdade de Ciencias, Universidade do Porto, Porto, Portugal.
    Self-calibrating total-mass controller for the neuromuscular blockade matching the anesthesiologists´ mindset2013Inngår i: Proc. 21st Mediterranean Conference on Control and Automation, 2013, s. 723-728Konferansepaper (Fagfellevurdert)
  • 287.
    Pelckmans, Kristiaan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för systemteknik. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Reglerteknik.
    MINLIP for the identification of monotone Wiener systems2011Inngår i: Automatica, ISSN 0005-1098, E-ISSN 1873-2836, Vol. 47, nr 10, s. 2298-2305Artikkel i tidsskrift (Fagfellevurdert)
  • 288.
    Pelckmans, Kristiaan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för systemteknik. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Reglerteknik.
    Randomized gossip algorithms for achieving consensus on the majority vote2013Inngår i: Proc. 11th IFAC International Workshop on Adaptation and Learning in Control and Signal Processing, 2013Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper studies a decentralized, randomized gossip algorithm for computing a majority vote amongst the binary decisions associated to n nodes organized in a fixed, ad-hoc network. It is indicated how this problem can be reduced to computing the global average using a standard, randomized gossip algorithm. Then, we illustrate how the majority vote problem allows one to formulate individual stopping rules deciding when an individual node makes its final verdict. Finally, we will provide an illustration of how well the algorithm and associated stopping rule behaves.

  • 289.
    Pelckmans, Kristiaan
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för systemteknik. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Reglerteknik.
    Cubo, Rubén
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för systemteknik. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Reglerteknik.
    Nuclear Norms for System Identification: a direct input-output approach2015Inngår i: Proc. 17th IFAC Symposium on System Identification, International Federation of Automatic Control , 2015, s. 644-649Konferansepaper (Fagfellevurdert)
  • 290.
    Pelckmans, Kristiaan
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för systemteknik. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Reglerteknik.
    Dai, Liang
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för systemteknik. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Reglerteknik.
    Bai, Er-Wei
    On the Convergence Analysis of the MINLIP Estimator2012Inngår i: Proceedings of the 16th IFAC Symposium on System Identification / [ed] Michel Kinnaert, 2012, s. 482-487Konferansepaper (Fagfellevurdert)
  • 291.
    Persson, Måns
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Waern, Tom
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Automatic adjustments of NC programs in machining centers2018Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    The goal of this master thesis was to automate the compensation of NC-programs. Automatic compensations can reduce errors and make the production more efficient. This is vital for increased precision and meeting the quality demands from the market.The project started with a study of how the feedback-loop between production and measurements was done at the time and also researching how the data could be sent between the different machines. This was done by researching solutions of similar problems and interviewing the machine operators. Simulations of how automation could be done with more in-depth measurements of the production machine were also made.The limitations was also evaluated. Research was done on errors and practical flaws which could be problematic for automation.The automation was implemented using Java to send the data between the measuring machine to the production machine. Furthermore a UI was created for the machine operators so that the information flow was under supervision at all times. The UI would suggest a compensation from a pre-programmed algorithm together with the measuring data, and the operator could then decide whether or not to diverge from the suggested compensation.

  • 292.
    Persson, Tobias
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Fredlund, Andreas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Motor control under strong vibrations2018Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
  • 293. Pierong, Rasmus
    et al.
    Nehrenheim, Emma
    Carlsson, Bengt
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för systemteknik. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Reglerteknik.
    Zambrano, Jesús
    Algae Based Wastewater Treatment Model Using The RWQM12016Inngår i: Proc. IWA World Water Congress & Exhibition: 2016, 2016Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    In this paper, we propose a model describing the dynamics of an algae based wastewater treatment process in an activated sludge environment. As the basis for the process modelling, the River Water Quality Model no. 1 (RWQM1) is chosen. In order to evaluate the applicability of the model to an activated sludge process, the proposed model is compared to the Activated Sludge Model no. 1 (ASM1).

  • 294. Pintelon, Rik
    et al.
    Hong, Mei
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för systemteknik. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Reglerteknik.
    Asymptotic uncertainty of transfer-function estimates using nonparametric noise models2007Inngår i: IEEE Transactions on Instrumentation and Measurement, ISSN 0018-9456, E-ISSN 1557-9662, Vol. 56, nr 6, s. 2599-2605Artikkel i tidsskrift (Fagfellevurdert)
  • 295. Quevedo, Daniel E.
    et al.
    Wigren, Torbjörn
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för systemteknik. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Reglerteknik.
    Design of Embedded Filters for Inner-Loop Power Control in Wireless CDMA Communication Systems2012Inngår i: Asian journal of control, ISSN 1561-8625, E-ISSN 1561-8625, Vol. 14, nr 4, s. 891-900Artikkel i tidsskrift (Fagfellevurdert)
  • 296. Rainforth, Tom
    et al.
    Naesseth, Christian A.
    Lindsten, Fredrik
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för systemteknik. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Reglerteknik.
    Paige, Brooks
    van de Meent, Jan-Willem
    Doucet, Arnaud
    Wood, Frank
    Interacting Particle Markov Chain Monte Carlo2016Inngår i: Proceedings of the 33rd International Conference on Machine Learning, 2016Konferansepaper (Fagfellevurdert)
  • 297. Relan, Rishi
    et al.
    Tiels, Koen
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för systemteknik. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Reglerteknik.
    Timmermans, Jean-Marc
    Schoukens, Johan
    Multiple-Input Single-Output Polynomial Nonlinear State-Space Model of the Li-ion Battery's Short-term Dynamics2018Konferansepaper (Fagfellevurdert)
    Abstract [en]

    A data-driven methodology is proposed to identify a multi-input single-output (MISO) polynomial nonlinear state-space model (PNLSS) for battery's short-term electrical response, starting from the best linear approximation of the electrical impedance at multiple operating conditions. Furthermore, a transient handling methodology is utilised to minimise the effect of transients arising due to concatenating data from multiple experiments during the identification of the PNLSS model. Experimental validation is done using the data acquired from the operating points lying in the nonlinear regime of an almost depleted battery in terms of the state of charge (SoC) i.e. between 2%-10% at temperatures between 5 degrees C-40 degrees C.

  • 298.
    Remouit, Flore
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Kamf, Tobias
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Abrahamsson, Johan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Engström, Jens
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Thruster model for Observation Class Remotely Operated VehicleInngår i: Ocean Engineering, ISSN 0029-8018, E-ISSN 1873-5258Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    For any small company or research group in offshore renewable energy, the costs to invest into Remotely Operate Vehicles (ROVs) for offshore operations are highly significant. There is however a potential to adapt and equip Observation Class ROVs (OCROVs) in order to make them perform light tasks, such as cable connection. OpenROV is a small and light OCROV with open source software, making it easy to implement tools, such as an autopilot. In this paper a model of the autopilot is presented. To be tested, it needs a model of the thrusters of the OpenROV. Those thrusters are hence tested, modelled in Simulink, and the experimental results are compared to the Matlab model.

  • 299. Ren, X
    et al.
    Wu, J
    Dey, Subhrakanti
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Signaler och System.
    Shi, L
    Attack allocation on remote state estimation in multi-systems: Structural results and asymptotic solution2018Inngår i: Automatica, ISSN 0005-1098, E-ISSN 1873-2836, Vol. 87, s. 187-194Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Abstract

    This paper considers optimal attack attention allocation on remote state estimation in multi-systems. Suppose there are M" role="presentation">

    independent systems, each of which has a remote sensor monitoring the system and sending its local estimates to a fusion center over a packet-dropping channel. An attacker may generate noises to exacerbate the communication channels between sensors and the fusion center. Due to capacity limitation, at each time the attacker can exacerbate at most N" role="presentation"> of the M" role="presentation"> channels. The goal of the attacker side is to seek an optimal policy maximizing the estimation error at the fusion center. The problem is formulated as a Markov decision process (MDP) problem, and the existence of an optimal deterministic and stationary policy is proved. We further show that the optimal policy has a threshold structure, by which the computational complexity is reduced significantly. Based on the threshold structure, a myopic policy is proposed for homogeneous models and its optimality is established. To overcome the curse of dimensionality of MDP algorithms for general heterogeneous models, we further provide an asymptotically (as M" role="presentation"> and N" role="presentation"> go to infinity) optimal solution, which is easy to compute and implement. Numerical examples are given to illustrate the main results.

  • 300.
    Rensfelt, Agnes
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för systemteknik. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Reglerteknik.
    Nonparametric identification of viscoelastic materials2006Licentiatavhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Viscoelastic materials can today be found in a wide range of practical applications. In order to make efficient use of these materials in construction, it is of importance to know how they behave when subjected to dynamic load. Characterization of viscoelastic materials is therefore an important topic, that has received a lot of attention over the years.

    This thesis treats different nonparametric methods for identifying the complex modulus of a viscoelastic material. The complex modulus is a frequency dependent material function, that describes the deformation of the material when subjected to uniaxial stress. With knowledge about this and other material functions, it is possible to simulate and predict how the material behaves under different kinds of dynamic loads. The complex modulus is often identified through wave propagation testing.

    An important aspect of identification is the accuracy of the estimates. For the identification to be as accurate as possible, it is important that the experimental data contains as much valuable information as possible. Different experimental condition, such as sensor locations and choice of excitation, can influence the amount of valuable information in the data. The procedure of determining optimal values for such design parameters is known as optimal experiment design.

    The first two papers of the thesis treats optimal experiment design for nonparametric identification of the complex modulus, based on wave propagation tests on large homogenous specimens. Optimal sensor locations is treated in the first paper, and optimal excitation in the second. In the third paper, a technique for estimating the complex modulus for a small pellet-sized specimen is presented. Three different procedures are considered, and an analysis of the accuracy of the estimates is carried out.

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