| 1. |
- Medvedev, Alexander, et al.
(author)
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A systematic synthesis of a neural network-based smoother
- 1992
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In: Proceedings of the 1992 IEEE International Symposium on Intelligent Control. - New York : IEEE Communications Society. - 0780305469 ; , s. 147-151
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Conference paper (peer-reviewed)abstract
- A feedforward neural network (FNN) implementation of a finite-memory smoother (FMS) is proposed. For a linear time-invariant dynamic system with measurement and process white noise, a single-layer FNN with delayed inputs is found to possess the same structure as the FMS designed by the least-squares method. The FNN-based FMS features definite speed advantages over conventional approaches and intrinsically finite process memory. Due to its parallel structure and absence of state vector integration, the FNN suffices for real-time applications. A numerical example illustrates the design procedure
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| 2. |
- Medvedev, Alexander, et al.
(author)
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Continuous finite-memory deadbeat observer
- 1992
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In: Proceedings of the 1992 American Control Conference. - : IEEE Communications Society. - 0780302109 ; , s. 1800-1806
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Conference paper (peer-reviewed)abstract
- A significant class of model-based control approaches uses Kalman filters or Luenberger observers to estimate the plant state vector. Infinite dynamic observer memory inflicts a phenomenon generally referred to as divergence. To overcome this drawback, a structure that intrinsically has finite process memory and does not need state vector integration is proposed in this paper. The observer uses a finite number of delayed input/output measurements to reconstruct the state vector with zero error being provided with a process history over its largest time-delay. This property resembles the deadbeat observer performance for discrete time systems. Moreover, the largest time-delay value puts a natural limit to the observer memory. The Luenberger observer analogy proved to be a useful tool for the observer analysis and paves the way toward observer optimization.
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| 3. |
- Medvedev, Alexander, et al.
(author)
-
Continuous-time deadbeat observation problem with application to predictive control of systems with delay
- 1994
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In: Kybernetika (Praha). - 0023-5954 .- 1805-949X. ; 30:6, s. 669-688
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Journal article (peer-reviewed)abstract
- A continuous-time deadbeat observation paradigm is discussed. Two observers are shown to estimate the state of a linear dynamic system in continuous time with respectively finite and infinite memory. Among other properties, BIBO-stability is proved for both structures. Based on the theory devised, deadbeat and asymptotic predictors for plants with delayed control are developed and shown to give rise to predictive feedback controllers assigning finite spectrum to the closed-loop system
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| 4. |
- Medvedev, Alexander, et al.
(author)
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Designing a flux observer for induction machines
- 1994
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In: The proceedings of the third IEEE Conference on Control Applications. - Piscataway, NJ : IEEE Communications Society. - 0780318722 ; , s. 453-458
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Conference paper (peer-reviewed)abstract
- Design aspects of a flux observer for induction machines are discussed. By making use of a second-order, complex-valued, state-space model of the induction machine dynamics, a stability criterion and observer estimation error bounds are obtained. An observer design method providing arbitrary convergence rate of the estimation error by means of a real-valued feedback gain matrix is introduced.
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| 5. |
- Medvedev, Alexander, et al.
(author)
-
External model control of a peristaltic pump
- 1994
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In: Advanced control of chemical processes (ADCHEM '94). - Oxford : Pergamon Press. - 0080422292 ; , s. 519-524
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Conference paper (peer-reviewed)
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| 6. |
- Medvedev, Alexander, et al.
(author)
-
External model control of a peristaltic pump
- 1994
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In: Elsevier IFAC Publications / IFAC Proceedings series. - 1474-6670. - 0080422292 ; 27:2, s. 519-524
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Journal article (peer-reviewed)abstract
- An observer-based approach to perfect disturbance rejection in linear continuous systems with delayed control is presented and exemplified by an application to a peristaltic pump. Disturbance rejection properties of the Smith Predictor are studied. A recently developed technique of continuous deadbeat observation is exploited to predict the disturbance signal which is described by a known dynamic model. It is shown that under certain algebraic conditions a disturbance estimate based control law is able to provide a disturbance-free output signal. The disturbance rejection scheme can be used in combination with any conventional control technique such as stabilizing or servo controller.
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| 7. |
- Medvedev, Alexander
(author)
-
Fault Detection by Continuous Dead-Beat Observation
- 1994
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In: Elsevier IFAC Publications / IFAC Proceedings series. - 1474-6670. - 0080422225 ; 27:5, s. 28-33
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Journal article (peer-reviewed)abstract
- An application of continuous-time deadbeat observation to fault analysis in linear dynamic systems is discussed. A finite memory residual chosen as a difference of two deadbeat state vector estimates is shown to be independent of both the state vector and control signal. The mapping of the fault mode to the residual is proven to be intrinsically BIBO-stable. Exploiting a decomposition of the “sliding-window” convolution operator, an upper bound for residual norm is derived and a fault detectability condition is obtained. Due to its simple structure, the deadbeat observer does not create a hard computational burden and can be easily implemented in real-time applications.
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| 8. |
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| 9. |
- Medvedev, Alexander, et al.
(author)
-
Feedforward time-delay structures in state estimation : finite memory smoothing and continuous deadbeat observers
- 1994
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In: IEE Proceedings - Control Theory and Applications. - : Institution of Engineering and Technology (IET). - 1350-2379 .- 1359-7035. ; 141:2, s. 121-129
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Journal article (peer-reviewed)abstract
- The paper investigates the possibilities of using a feedforward time-delay structure for state estimation and smoothing in linear continuous dynamic systems. A fixed-lag finite-memory smoother and a continuous deadbeat observer are shown to be described by a linear combination of delayed measurements of the system inputs and outputs. To facilitate implementation of the observer-based controllers an infinite-memory deadbeat observer is introduced. Design methods are illustrated by numerical examples.
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| 10. |
- Medvedev, Alexander, et al.
(author)
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On perfect disturbance rejection
- 1993
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In: Proceedings of the 32nd IEEE Conference on Decision and Control. - Piscataway, NJ : IEEE Communications Society. - 0780312988 ; , s. 1324-1329
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Conference paper (peer-reviewed)abstract
- A new observer-based approach to perfect disturbance rejection in linear continuous systems is introduced. A technique of continuous deadbeat observation is exploited to estimate the disturbance signal described by a known dynamic model. A realization condition in the form of linear algebraic equations is derived. It is shown that the introduced disturbance rejection scheme can be used in combination with any conventional control technique such as stabilization or servo control
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