| 1. |
- Andersson, Magnus, et al.
(författare)
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A Simulation and Animation Tool for Studying Multivariable Control
- 2002
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Ingår i: Proceedings of the 15th IFAC World Congress. - 9783902661746 ; , s. 1432-1432
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Konferensbidrag (refereegranskat)abstract
- A simulation and animation tool for education in multivariable control is presented. The purpose of the tool is to support studies of various aspects of multivariable dynamical systems and design of multivariable feedback control systems. Different ways to use this kind of tool in control education are also presented and discussed.
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| 2. |
- Fliess, M, et al.
(författare)
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An Algebraic Approach to Linear and Nonlinear Control
- 1993
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Ingår i: Essays on Control. - Boston ; Basel : Birkhäuser. - 0817636706 - 3764336706 ; , s. 223--267
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Bokkapitel (refereegranskat)abstract
- The analysis and design of control systems has been greatly influenced by the mathematical tools being used. Maxwell introduced linear differential equations in the 1860’s. Nyquist, Bode and others started the systematic use of tranfer functions, utilizing complex analysis in the 1930’s. Kalman brought forward state space analysis around 1960. For nonlinear systems, differential geometric concepts have been of great value recently. We will argue here that algebraic methods can be very useful for both linear and nonlinear systems. To give some motivation we will begin by looking at a few examples.
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| 3. |
- Gerdin, Markus, et al.
(författare)
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Global Identifiability of Complex Models, Constructed from Simple Submodels
- 2007
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Ingår i: Modeling, Estimation and Control. - Linköping : Linköping University Electronic Press. - 9783540735694 ; , s. 123-133
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- It is a typical situation in modern modeling that a total model is built up from simpler submodels, or modules, for example residing in a model library. The total model could be quite complex, while the modules are well understood and analysed. A procedure to decide global parameter identifiability for such a collection of model equations of differential-algebraic nature is suggested. It is shown how to make use of the natural modularization of the model structure. Basically, global identifiability is obtained if and only if each module is identifiable, and the connecting signals can be retrieved from the external signals, without knowledge of the values of the parameters.
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| 4. |
- Gerdin, Markus, 1977-, et al.
(författare)
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On Identifiability of Object-Oriented Models
- 2006
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Ingår i: Proceedings of the 14th IFAC Symposium on System Identification. - 9783902661029 ; , s. 820-825
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Konferensbidrag (refereegranskat)abstract
- When estimating unknown parameters, it is important that the model is identifiable so that the parameters can be estimated uniquely. For nonlinear differential-algebraic equation models with polynomial equations, a differential algebra approach to examine identifiability is available. This approach can be slow, so the present paper describes how this method can be modularized for object-oriented models. A characteristic set of equations is computed for components in model libraries, and stored together with the components. When an object-oriented model is built using such models, identifiability can be examined using the stored equations.
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| 5. |
- Gerdin, Markus, 1977-, et al.
(författare)
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On Parameter and State Estimation for Linear Differential-Algebraic Equations
- 2007
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Ingår i: Automatica. - Linköping : Elsevier. - 0005-1098 .- 1873-2836. ; 43:3, s. 416-425
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Tidskriftsartikel (refereegranskat)abstract
- The current demand for more complex models has initiated a shift away from state-space models towards models described by differential-algebraic equations (DAEs). These models arise as the natural product of object-oriented modeling languages, such as Modelica. However, the mathematics of DAEs is somewhat more involved than the standard state-space theory. The aim of this work is to present a well-posed description of a linear stochastic differential-algebraic equation and more importantly explain how well-posed estimation problems can be formed. We will consider both the system identification problem and the state estimation problem. Besides providing the necessary theory we will also explain how the procedures can be implemented by means of efficient numerical methods.
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| 6. |
- Gerdin, Markus, 1977-, et al.
(författare)
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Parameter Estimation in Linear Differential-Algebraic Equations
- 2003
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Ingår i: Proceedings of the 13th IFAC Symposium on System Identification. - Linköping : Linköping University Electronic Press. - 9780080437095 ; , s. 1530-
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Konferensbidrag (refereegranskat)abstract
- This report describes how parameter estimation can be performed in linear DAE systems. Both time domain and frequency domain identification are examined. The results are exemplified on a small system. A potential application for the algorithms is to make parameter estimation in models generated by a modeling language like Modelica.
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| 7. |
- Gerdin, Markus, 1977-, et al.
(författare)
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Well-Posedness of Filtering Problems for Stochastic Linear DAE Models
- 2005
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Ingår i: Proceedings of the 44th IEEE Conference on Decision and Control and European Control Conference. - Linköping : Linköping University Electronic Press. - 0780395670 ; , s. 350-355
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Konferensbidrag (refereegranskat)abstract
- Modern modeling tools often give descriptor or DAE models, i.e., models consisting of a mixture of differential and algebraic relationships. The introduction of stochastic signals into such models in connection with filtering problems raises several questions of well-posedness. The main problem is that the system equations may contain hidden relationships affecting variables defined as white noise. The result might be that certain physical variables get infinite variance or contain formal differentiations of white noise. The paper gives conditions for well-posedness in terms of certain subspaces defined by the system matrices.
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| 8. |
- Glad, Torkel, 1947-
(författare)
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A Differential Algebra Representation of the RGA
- 2000
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Ingår i: Proceedings of the 14th International Symposium on Mathematical Theory of Networks and Systems. - Linköping : Linköping University Electronic Press. ; , s. 169-178
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Konferensbidrag (refereegranskat)abstract
- Extentions of the RGA (relative gain array) technique to nonlinear systems are considered. The steady-state properties are given by an array of nonlinear functions. It is shown that the corresponding dynamic description can be calculated using a reduction algorithm from differential algebra.
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| 9. |
- Glad, Torkel, 1947-, et al.
(författare)
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Aircraft Pitch Attitude Control using Backstepping
- 2000
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Ingår i: Proceedings of Reglermöte 2000. - Linköping : Linköping University Electronic Press. ; , s. 143-148
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- A nonlinear approach to the automatic pitch attitude control problem for a generic fighter aircraft is presented. A nonlinear model describing the longitudinal equations of motion in strict feedback form is derived. Backstepping is utilized for the construction of a globally stabilizing controller with a number of free design parameters. Two tuning schemes are proposed based on the desired locally linear controller properties. The controller is evaluated using the HIRM fighter aircraft model.
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| 10. |
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