Measurement and Control
Published Research Papers from Vol. 1 (2005) to Vol. 9 (2013) ISSN: 1743-9310
Mediterranean Journal of Measurement and Control covers all areas of applications in control, measurement, and instrumentation. Its scope encompasses cutting-edge research and development, education and industrial applications. The journal publishes high standard peer-reviewed papers designed to appeal to both researchers and practitioners.
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A ROBUST TCSC CONTROLLER DESIGN FOR ENHANCING POWER SYSTEMS DAMPING

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A. H. M. A. Rahim, E. P.Nowicki, D. Westwick
This paper presents the design of a robust damping controller for a thyristor controlled series capacitor (TCSC) of a power system, by using the loop-shaping techniques. This eliminated the complex computations that usually needed in such designs. Simulations results demonstrate that fixed parameter TCSC controller provides very good damping properties even with severely disturbed conditions and at significant overloads.

ON A MODELING APPROACH OF DYNAMIC SYSTEMS: A GUIEDED TOUR

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Magdi S. Mahmoud
This paper provides an overview of a modeling approach to the analysis, synthesis and feedback control of dynamic systems. The salient feature of this approach is the focus on the internal structural properties of the system under consideration. It is shown that a postulated system structure with a fusing mechanism can generate classes of dynamic systems encompassing complex interconnected systems, multi-time-scale systems, uncertain systems, time-delay systems. The paper is further appended by extensive list of references supporting our approach.

MULTIVARIABLE FUZZY CONTROLLER FOR THREE HYDRAULICALLY COUPLED TURBINES

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M. Mahmoud, K. Dutton, M. Denman
One of the important industrial areas involving complex nonlinear dynamics and control problems is that of hydropower plants. A hydropower plant that has multiple numbers of hydraulic turbines sharing a common conduit (tunnel or penstock) may be prone to instability and oscillatory behaviour if the interacting disturbances between its turbines due to the hydraulic coupling are not controlled. In this paper a multivariable fuzzy controller is designed and simulated exclusively to control, simultaneously, three hydraulically coupled turbines under nonlinear process conditions. It may replace a commonly used control arrangement of three independent PID turbine governors.

SOME COMMENTS ON THE CONTROL OF LINEAR AND BILENEAR SINGULARLY PERTURBED SYSTEMS UNDER FAST SAMPLING

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M. Djemai, J. P. Barbot, L. Fridman
In this paper, we present a fast discretization scheme of two-time-scale linear and bilinear continuous time system. This discretization scheme consists of using a fast sampling-time period that is suitably chosen with respect to the fast dynamic, and leads to a digital control adapted to the system under study.

NONLINEAR CONTROL DESIGN USING THE EXTENDED JORDAN CONTROLLABLE CANONICAL FORM

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K. Busawon, M. Saif, D. Tingey
This paper deals with the design of a controller for a class of nonlinear systems. The controller design is based on the transformation of the system into an extended Jordan controllable canonical form. It is shown that such a canonical form facilitates the design of the controller, since it introduces additional degrees of freedom in terms of real-valued functions of the state and which can in particular, be used as control design parameters. The design procedure of the controller is illustrated using two typical examples and their corresponding performances are shown via simulation.

NEW RESULTS ON RESILIENT CONTROL OF CONTINUOUS-TIME SYSTEMS WITH POLYTOPIC UNCERTAINTIES

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Magdi S. Mahmoud, Hazem Nounou
A class of linear continuous-tune systems with convex-bounded parametric uncertainties in all system matrices and subject to additive controller gain perturbations is fully examined in this paper. The control objective is to design resilient feedback stabilization schemes using guaranteed cost control and control approaches. Initially, the case of state-variable measurements is considered, thereby leading to static feedback control. Then we move to examine the case of output-variable measurements to design dynamic output feedback control. The solution of the problem under consideration in all cases is cast as convex optimization over linear matrix inequalities which led to the derivation of sufficient conditions for closed-loop robust quadratic stability. Several system examples are provided throughout the paper to illustrate the theoretical developments.

FUZZY SUPERVISORY CONTROL AND OPTIMIZATION SYSTEM FOR A CASCADED RESERVOIRS HYDROPOWER PLANT

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M. Mahmoud, K. Dutton, M. Denman
Cascaded reservoirs hydropower plants are complex nonlinear systems that involve interacting input and output nonlinear parameters and difficult optimization and scheduling tasks. For the purpose of minimizing the non hydraulic power production expenses by means of maximizing the cascaded reservoirs hydropower plant’s operational envelope, a fuzzy supervisory control and optimization system is designed and simulated so as it monitors the cascaded reservoirs’ rates of discharge/accumulation and alters the operational set points of the local fuzzy control systems which control the hydropower plant’s sub-systems, in real time, so that a maximized power plant operational envelope is always maintained.

ADAPTIVE CONTROL TECHNIQUE USING MULTILAYER FEEDFORWARD NEURAL NETWORKS

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Hussain Al-Duwaish
This paper presents a new method for implementing adaptive controllers using multilayer feedforward neural networks (MFNN). The controlled process is approximated at each sampling time by a linear time-invariant (LTI) model. The proposed adaptive controller is a combination of a parameter estimation algorithm to estimate the parameters of the process and an adaptation algorithm for the connection weights of the neural network. An adaptation algorithm to adjust the connection weights of the neural network has been derived. Simulation results are included to demonstrate the feasibility and the adaptive properties of the proposed controller.

ROBUST INDUCTION MOTOR CONTROL WITH SLIDING MODE OBSEVER

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Moussa Boukhnifer, Boualem Hemici, Mohamed S. Boucherit
In this paper, a robust control technique for an induction motor is presented. This motor is fed by five-level inverter controlled by the triangulo-sinusoidal strategy with four bipolar carriers. The control algorithm uses robust regulators designed by the H∞ loop shaping approach associated with indirect field oriented control. The sliding mode observer is used to observe the rotor flux in the induction motor. The simulation results show that the controllers stabilize the system and reject the disturbances when the system is subjected to uncertainties, which their norms are lower than the maximum stability margin.

ON ELLIPTIC SYSTEMS INVOLVING SCHRODINGER OPERATORS

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H. M. Serag, A. H. Qamlo
In this paper some elliptic systems involving Schrodinger operators defined on an unbounded domain have been investigated. The necessary and sufficient conditions for having the maximum principle and existence of positive solutions for such systems have been obtained. It has been proved that these conditions ensure the existence of optimal control.