| 1. |
- Fortell, Håkan
(författare)
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A Generalized Normal Form and its Application to Sliding Mode Control
- 1995
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Ingår i: Proceedings of the 34th IEEE Conference on Decision and Control. - Linköping : Linköping University. - 0780326857 ; , s. 13-18 vol.1
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- In this paper it is shown how a normal form, corresponding to that of affine state space systems, can be calculated for a dynamics defined in the differential algebraic framework. The construction of the normal form is based on a generalization of the Lie derivative where the state derivatives are eliminated using Grobner bases. It is also shown how the generalized normal form can be used in the context of sliding mode control.
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| 2. |
- Hjalmarsson, Håkan, 1962-, et al.
(författare)
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Composite modeling of transfer functions
- 1995
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Ingår i: Proceedings of the IEEE Conference on Decision and Control. - New Orleans, LA, USA : Institute of Electrical and Electronics Engineers (IEEE). - 0780326857 ; 40:5, s. 820-832
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Konferensbidrag (refereegranskat)abstract
- The problem under consideration is how to estimate the frequency function of a system and the associated estimation error when a set of possible model structures is given and when one of them is known to contain the true system. The 'classical' solution to this problem is to, firstly, use a consistent model structure selection criterium to discard all but one single structure. Secondly, estimate a model in this structure and, thirdly, conditioned on the assumption that the chosen structure contains the true system, compute an estimate of the estimation error. However, for a finite data set one cannot guarantee that the correct structure is chosen and this 'structural' uncertainty is lost in the previously mentioned approach. In this contribution a method is developed that combines the frequency function estimates and the estimation errors from all possible structures into a joint estimate and estimation error. Hence, this approach by-passes the structure selection problem. This is accomplished by employing a Bayesian setting.
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| 3. |
- Isaksson, Alf, et al.
(författare)
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Comparison of some Kalman Filter based Methods for Maneuver Tracking and Detection
- 1995
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Ingår i: Proceedings of the 34th IEEE Conference on Decision and Control. - 0780326857 ; , s. 1525-1531 vol.2
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Konferensbidrag (refereegranskat)abstract
- This paper describes general modelling of radar target tracking scenarios. Manoeuvres are modelled using a stochastic continuous-time model. The goal of this paper is twofold: to compare two different choices of velocity coordinates, and to compare two different manoeuvre models leading to pruning and merging of the filter bank respectively. Simulation results indicate that velocity and heading should be used as states. Regarding merging and pruning there seems to be a trade-off between performance at the beginning of the turn and the steady-state accuracy.
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| 4. |
- Johansson, Rolf, et al.
(författare)
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An Algorithm for Continuous-Time State Space Identification
- 1995
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Ingår i: Proceedings of the IEEE Conference on Decision and Control. - 0191-2216. - 0780326857 ; 1, s. 721-722
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Konferensbidrag (refereegranskat)abstract
- We have developed a system identification algorithm to fit continuous-time state-space models to data. The methodology includes a continuous-time operator translation, permitting an algebraic reformulation and the use of subspace and realization algorithms. The new approach has proved effective in identification and modeling of ultrasonic echo applications.
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| 5. |
- Ljung, Lennart, 1946-, et al.
(författare)
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Estimating the Total Model Error from Standard Model Validation Tests
- 1995
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Ingår i: Proceedings of the 34th IEEE Conference on Decision and Control. - 0780326857 ; , s. 1651-1656 vol.2
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Konferensbidrag (refereegranskat)abstract
- The problem of assessing the quality of a given, or estimated model is a central issue in system identification. Classical model validation procedures are considered. We discuss the principles by which we reach confidence in a model through such validation techniques, and also how the distance to a “true” description can be estimated this way. In particular we stress how the typical model validation procedure gives a direct measure of the model error of the model test, without referring to its ensemble properties. Several model error bounds are developed for various assumptions about the disturbances entering the system.
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| 6. |
- McKelvey, Tomas
(författare)
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Asymptotic Variance Expressions for a Frequency Domain Subspace based System Identification Algorithm
- 1995
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Ingår i: Proceedings of the 34th IEEE Conference on Decision and Control. - 0780326857 ; , s. 1234-1239 vol.2
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Konferensbidrag (refereegranskat)abstract
- A frequency domain identification algorithm is analyzed. The algorithm identifies state-space models given samples of the frequency response function given at equidistant frequencies. A first order perturbation analysis is performed revealing an explicit expression of the resulting transfer function perturbation. Stochastic analysis show that the estimate is asymptotically (in data) normal distributed and an expression of the resulting variance is derived. Monte Carlo simulations illustrates the validity of the derived variance also for the nonasymptotic case and a comparison with the Cramer-Rao lower bound shows that the algorithm is suboptimal.
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| 7. |
- McKelvey, Tomas
(författare)
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Frequency Weighted Subspace Based System Identification in the Frequency Domain
- 1995
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Ingår i: Proceedings of the 34th IEEE Conference on Decision and Control. - 0780326857 ; , s. 1228-1233 vol.2
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Konferensbidrag (refereegranskat)abstract
- Frequency weighting capabilities are introduced in a subspace based frequency domain identification algorithm. Weighting matrices constructed from the impulse response of weighting filters are used to weight a Hankel matrix prior of deriving the signal subspace by the singular value decomposition. The resulting algorithm is shown to asymptotically produce models which are the frequency weighted balanced truncation of the identified system. An illustrative example shows the applicability of the method for finite data.
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| 8. |
- Medvedev, Alexander
(författare)
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Continuous least-squares observers with applications
- 1995
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Ingår i: Proceedings of the 34th IEEE Conference on Decision and Control. - Piscataway, NJ : IEEE Communications Society. - 0780326857 ; , s. 321-326
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Konferensbidrag (refereegranskat)abstract
- A wide class of continuous least-squares (LS) observers is treated in a common framework provided by the pseudodifferential operator paradigm. It is shown that for the operators whose symbols satisfy certain conditions, the continuous LS-observer always exists provided observability of the plant. The general result is illustrated by an LS-observer stemmed from a sliding-window convolution operator. Applications to state feedback control and fault detection are discussed. A wide class of continuous least-squares (LS) observers is treated in a common framework provided by the pseudodifferential operator paradigm. It is shown that for the operators whose symbols satisfy certain conditions, the continuous LS-observer always exists provided observability of the plant. The general result is illustrated by an LS-observer stemmed from a sliding-window convolution operator. Applications to state feedback control and fault detection are discussed. A wide class of continuous least-squares (LS) observers is treated in a common framework provided by the pseudodifferential operator paradigm. It is shown that for the operators whose symbols satisfy certain conditions, the continuous LS-observer always exists provided observability of the plant. The general result is illustrated by an LS-observer stemmed from a sliding-window convolution operator. Applications to state feedback control and fault detection are discussed.
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| 9. |
- Plantin, Jonas, et al.
(författare)
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Symbolic Algebraic Discrete Systems Theory - Applied to a Fighter Aircraft
- 1995
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Ingår i: Proceedings of the 34th IEEE Conference on Decision and Control. - 0780326857
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Konferensbidrag (refereegranskat)abstract
- Symbolic algebraic modeling and analysis techniques for DEDS are applied to the landing gear subsystem in the new Swedish fighter aircraft, SAS 39 Gripen. The authors' methods are based on polynomials over finite fields. Polynomials are used to represent the basic dynamic equations for the processes (controller and plant) as well as static properties of these. Temporal algebra (or temporal logic) is used to represent specifications of system behavior. The authors use this approach to model the landing gear controller from the complete implementation in Pascal. The authors also provide temporal algebra interpretations of the specifications made available to them. Finally the authors perform a number of symbolic analyses on the complete process (controller and plant). This project is a first demonstration of possible uses of these methods and tools and it shows that these methods and tools scale to a problem of a non-trivial size, i.e. of the size found in complex system designs such as the JAS 39.
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| 10. |
- Tikku, Asha, et al.
(författare)
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Worst-Case Identification in L1 for F.I.R. Linear Systems
- 1995
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Ingår i: Proceedings of the 34th IEEE Conference on Decision and Control. - 0780326857 ; , s. 2998-3003 vol.3
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Konferensbidrag (refereegranskat)abstract
- Investigates the sample complexity of a time-domain worst-case system identification problem for finite impulse response linear systems. The sample complexity of identification is the duration of the minimum length identification experiment that must be run in order to identify the unknown system to within a specified worst-case error bound. The identification criterion the authors treat is worst-case with respect to both modeling uncertainty and noise. In this paper the authors derive bounds on the sample complexity under various noise models. The authors' results demonstrate how the character of noise affects the complexity of identification. A consequence of these results is that the complexity of identification can be quite reasonable if the distribution of the energy of the noise signal satisfies mild constraints.
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