Last issue
2017 (vol. 27) - Number 2


W. Bozejko, M. Wodecki:

Discrete Systems: Theory and Applications. Special issue.



G. Bocewicz, Z. Banaszak, I. Nielsen:

Delivery-flow routing and scheduling subject to constraints imposed by vehicle flows in fractal-like networks



W. Bozejko, A. Gnatowski, R. Idzikowski, M. Wodecki:

Cyclic flow shop scheduling problem with two-machine cells



W. Bozejko, M. Uchronski,, Z. Chaczko, M. Wodecki:

Parallel patterns determination in solving cyclic flow shop problem with setups



J. Brodny, S. Alszer, J. Krystek, M. Tutak:

Availability analysis of selected mining machinery



K. Chmielewska, D. Formanowicz, P. Formanowicz:

The effect of cigarette smoking on endothelial damage and atherosclerosis development - modeled and analyzed using Petri nets



A. Galuszka, J. Krystek, A. Swierniak, T. Grzejszczak, C. Lungoci:

Information management in passenger traffic supporting system design as a multi-criteria discrete optimization task



M. Kardynska, J. Smieja:

Sensitivity analysis of signaling pathway models based on discrete-time measurements



J. Kasprzyk, P. Krauze, S. Budzan, J. Rzepecki:

Vibration control in semi-active suspension of the experimental off-road vehicle using information about suspension deflection



M. Koryl, D. Mazur:

Towards emergence phenomenon in business process management



M. Koryl:

Active resources concept of computation for enterprise software



H. Krawczyk, M. Nykiel:

Mobile devices and computing cloud resources allocation for interactive applications



W. Mitkowski, W. Bauer, M. Zagórowska:

Discrete-time feedback stabilization



J. Pempera:

An exact block algorithm for no-idle RPQ problem



K. Rzosinska, D. Formanowicz, P. Formanowicz:

The study of the influence of micro-environmental signals on macrophage differentiation using a quantitative Petri net based model



K. Skrzypczyk , M. Mellado:

Vehicle navigation in populated areas using predictive control with environmental uncertainty handling



W. Bozejko, J. Pempera, M. Wodecki:

A fine-grained parallel algorithm for the cyclic flexible job shop problem




ACS Abstract:

2004 (Volume 14)
Number 3/4
1. An adaptive control scheme for nonholonomic mobile robot with parametric uncertainty
2. Numerical determination of quadratic-optimal regulator for linear systems with constraints
3. Model identification for Active Noise Control - a case study
4. An alternative algorithm to EAXCT self-tuning
5. On state and output stabilization of discrete delay systems
6. A quasi-LPV model for gain-scheduling canal control


An adaptive control scheme for nonholonomic mobile robot with parametric uncertaintyDownload full PDF article
Faical Mnif
(Institut National des Sciences Appliquees et de Technologie, Tunisia)
Farid Touati
(Sultan Qaboos University, Oman)

This paper addresses the problem of the adaptive stabilization of a nonholonomic mobile robot. A discontinuous adaptive state feedback controller is derived to achieve global stability and convergence of the trajectories of the closed loop system in the presence of parameter modeling uncertainty. This task is achieved by a non smooth transformation in the original system followed by the derivation of smooth time invariant control in the new coordinates. The stability and convergence analysis is built on Lyapunov stability theory.

keywords: nonholonomic systems, adaptive control, car-like vehicle.

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Numerical determination of quadratic-optimal regulator for linear systems with constraintsDownload full PDF article
Jan Cvejn
(Technical University of Liberec, Czech Republic)

The paper describes a way of determination of quadratic-optimal regulator for linear continuous and discrete systems with constraints. The method is based on direct numerical minimization of the quadratic criterion expressing the quality of control. Constant regulator matrix, independent on the starting state, is obtained as a result. Due to the constraints the optimal regulator however depends on initial state. Therefore, the problem formulation was modified by using an extended criterion of optimality that guarantees quality behavior for any initial state within a given set.

keywords: quadratic optimal regulators, control of linear systems, optimal control with constraints, criterion functions, optimization problems.

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Model identification for Active Noise Control - a case studyDownload full PDF article
Jerzy Kasprzyk
(Silesian University of Technology, Poland)

One of the typical problems in active noise control (ANC) system design is identification of an electro-acoustic plants. In the example considered models are required to parameterize an adaptive feedforward ANC system creating a local 3-dimensional zone of quiet in an enclosure. The structure of a multi-channel control system involves the necessity of identification of transfer functions for secondary and acoustic feedback paths. Plants to be identified are of MISO (Multi-Input-Single-Output) type with three inputs. The problem of designing the identification experiment is considered and different excitation signals are tested. Complexity of the plant implies that identified models should be of a very high order and the ordinary least squares method is the most applicable for model fitting in this case. Since there are no prerequisites for model structure assumption, delays and polynomial orders are to be identified too. This is done by iterative procedure of testing different structures and selection this one which minimizes the BIC criterion. The results of real-world experiments are presented and accuracy of frequency response estimates of parametric models is proved using a classical spectral analysis.

keywords: Active Noise Control, process identification, parameter estimation, frequency response, models.

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An alternative algorithm to EAXCT self-tuningDownload full PDF article
Zbigniew Świder and Leszek Trybus
(University of Technology, Rzeszów, Poland)

An alternative to EXACT self-tuning algorithm available in PID controllers from Emerson-Foxboro is presented. The same specifications, i.e. overshoot and damping of the error transient, are used. Tuning steps are performed along contour lines of three template surfaces which represent overshoot, damping and frequency in terms of loop gain and controller zero. The template surfaces are generated by simulation of PID loop with time-constant-plus-delay plant whose time constant is the same as delay. The algorithm applies simple 2nd order model for oscillating and damped transients. Convergence rate is similar to that of EXACT. Simplified version of the algorithm has been implemented in an industrial controller.

keywords: self-tuning, PID control, adaptive control.

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On state and output stabilization of discrete delay systemsDownload full PDF article
Jamila Karrakchou
(LERMA, EGT, Ecole Mohammadia d'ing?nieurs, Maroc)
Abedlwahed Namir, Fouad Lahmidi and Boubker Daafi
(Faculté des Sciences Ben M'Sik, Maroc)

The problem of the state and output stabilization of discrete-time delay systems on Hilbert spaces is considered. Sufficient and necessary conditions for the state stabilization are given. Analogue results for the output stabilization are presented.
This work is organized in three sections. The state stabilization problem is examined in section 2. The three principle notions of stability and stabilizability (uniform, strong and weak) are investigated. Using the state space technique, it is shown that this problem can be tackled considering an equivalent non delayed system. Sufficient and necessary conditions for the stabilization of the new system are then established. Using these results and similar methods, sufficient and necessary conditions for the output stabilization are developed in section 3. To illustrate this work, some examples are given.

keywords: Discrete-time system, delay system, stability, state stabilization, output stabilization.

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A quasi-LPV model for gain-scheduling canal controlDownload full PDF article
Yolanda Bolea, Vicenc Puig, Joaquin Blesa, Manuel Gómez and Jose Rodellar
(Technical University of Catalonia, Spain)

In this paper, a quasi-linear parameter-varying (quasi-LPV) model for canal control is proposed. This model relates the downstream level with the gate opening and takes into account the non-linearity, the variation of the model parameters and the dependence with the operating point. Thus, this kind of a model represents in a more accurate way the canal behavior than a linear time invariant (LTI) model. Moreover, it is suitable as for the conventional gain-scheduling as for a rigorous and formal (LPV or fuzzy) gain-scheduling control design using linear matrix inequality (LMI) tools. Finally, the proposed LPV model has been used to design a conventional gain-scheduling (GS) PI controller and tested on a single pool canal.

keywords: LPV models, LTI models, distributed parameter systems, gain-scheduling control, and environmental systems.

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