A. FILIPESCU, F. LEITE, U. NUNES: ROBUST DISCRETE-TIME ADAPTIVE SLIDING MODE WMR TRAJECTORY TRACKING AND PARAMETER IDENTIFICATION
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Radu-Emil PRECUP and Stefan PREITL: DESCRIBING FUNCTION METHOD FOR PI-FUZZY CONTROLLED SYSTEMS STABILITY ANALYSIS
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Nicolaos Antonio CUTULULIS: FEEDBACK LINEARIZATION CONTROL OF WIND POWER SYSTEMS
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Jonas REIJNIERS and Herbert PEREMANS: TRANSDUCER-SHAPE OPTIMIZATION FOR ANGLE ESTIMATION OF A BROADBRAND MONAURAL SONAR SYSTEM
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A. FILIPESCU, L. DUGARD, J. M. DION: ROBOTS CONTROL BY ADAPTIVE GAIN SMOOTH SLIDING OBSERVER-CONTROLLER AND PARAMETER IDENTIFICATION
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Mihai CULEA: ON THE PERFORMANCES OF DIFFERENT TYPES OF CONTROLLERS FOR ACTIVE POWER FILTERS
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Vasile Sima: COMPUTATIONAL EXPERIENCE IN SOLVING LARGE LINEAR MATRIX EQUATIONS FOR AUTOMATIC CONTROL
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Gheorghe BALUTA: OPEN-LOOP CONTROL OF A BIPOLAR STEPPER MOTORS USING THE SPECIALIZED INTEGRATED CIRCUITS
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Mihaela-Hanako MATCOVSCHI, Octavian PASTRAVANU: COMPONENTWISE STABILITY OF DISCRETE-TIME INTERVAL BIDIRECTIONAL ASSOCIATIVE MEMORIES
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Ion Voncila, Cristian Munteanu, Razvan Buhosu, Marcel Oanca: COMPARATIVE ANALYSIS OF THE BEHAVIOR OF COAXIAL AND FRONTAL COUPLINGS – WITH PERMANENT MAGNETS – IN HIGH TEMPERATURE ENVIRONMENTS
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Clara Ionescu, Robin De Keyser: SOME FREQUENCY DOMAIN CONSIDERATIONS UPON HUMAN RESPIRATORY MECHANICS
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Dan Munteanu, Severin Bumbaru: DEVELOPMENT OF A GENERIC RECOMMENDER SYSTEM
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Octavian Paul Rotaru, Marian Dobre, Mircea Petrescu: VENDOR-INDEPENDENT DATABASE APPLICATIONS – AN ARCHITECTURAL APPROACH
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Munteanu Traian, Vasilache Cristian, Bivol Ion, Roºu Emil: SOME CONSIDERATION REGARDING MOTION CONTROL AND PLANNING
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Nasta TANASESCU: SYNTHESIS METHODOLOGY FOR ACTIVE ELEMENT USING IMPEDANCES –BASED BOND GRAPH METHODS
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Daniela DANCIU, Vladimir RASVAN: ON THE STABILITY OF THE CELLULAR NEURAL NETWORKS WITH TIME LAGS
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Matei Vinatoru, Eugen Iancu, Camelia Maican: MODELLING AND SIMULATION OF THE POWER PLANT STEAM SUPERHEATERS
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Viorel DUGAN, Razvan SOLEA, Daniela GHINITA: FUZZY MODELS AS DECISION-SUPPORT APPLICATIONS OF ELECTRICAL ENERGY TARIFFING
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Abstract: In this paper a discrete-time adaptive sliding mode controller for three wheels mobile robot (WMR) is presented. The dynamical model with time-varying mass has been taken into account. The sliding-mode controller has designed on two components, corresponding to angular and linear displacement, respectively. In order to accomplish the robustness against parameter uncertainties an on-line closed loop identification scheme is proposed. To the both of them, angular and linear displacement controllers, parameter estimates depending of the robots mass, on-line updated, are used.

Keywords: discrete-time, robust adaptive sliding mode controller, wheeled mobile robot

 

Abstract: The paper proposes a global stability analysis method dedicated to fuzzy control systems containing Mamdani PI-fuzzy controllers with output integration to control SISO linear / linearized plants. The method is expressed in terms of relatively simple steps, and it is based on: the generalization of the describing function method for the considered fuzzy control systems to the MIMO case, the approximation of the describing functions by applying the least squares method. The method is applied to the stability analysis of a class of PI-fuzzy controlled servo-systems, and validated by considering a case study.

Keywords: fuzzy control, describing functions, stability analysis, PI controllers, servosystems.

 

Abstract: This paper focuses on the development of a feedback linearization control for a variable speed fixed pitch wind turbine driving a permanent magnet synchronous generator. The power system is considered to operate on an insular grid. The feedback linearization controller aims to maximize the energy captured from the wind, for varying wind speeds. Numerical simulation results are presented to demonstrate the effectiveness of the feedback linearization controller.

Keywords: Wind generation; Windmills; Feedback linearization; Permanent magnet; Synchronous generator;

 

Abstract: In this paper we describe a procedure for the search of the optimal transducer geometry for a monaural, broadband sonar system. We restrict ourselves to a simple transducer morphology that can be technologically realized: a radially symmetric two-dimensional piston transducer with adaptable electrode shape. We use a genetic algorithm to obtain the `optimal' geometry, and show that the generated transducer performs significantly better in simulated localization experiments.

Keywords: artificial intelligence, bionics, computer simulation, digital signal processing, mobile robots.

 

Abstract: An adaptive gain, smooth sliding observer-controller are developed to control uncertain parameters, -degree of freedom rigid robotic manipulators. Furthermore, an on-line, closed loop identification scheme, for time-varying parameters is proposed in order to obtain useful information despite loads, external disturbances and faults detection. In order to reduce the chattering, a smooth switching function (parameterised tangent hyperbolic function) is used instead of pure relay one, into the observer and the controller. The gains of the switching functions are adaptively updated, depending on the estimation error and tracking error, respectively. By using adaptive gains, the transient and tracking responses are improved. Simulation results with a two degree of freedom (DOF) robot manipulator are presented to show the interest of the approach.

Keywords: Robotic manipulators, adaptive gain, smooth sliding observer-controller, parameter identification.

 

Abstract: This paper analyses the performances of three different types of controllers for shunt active power filters. The controllers are used in the d-q frame, the same frame in which the reference signal for the 5th and 7th harmonics is injected. Performance is evaluated based on amplitude and phase error between the injected reference and the output of the active power filter.

Keywords: Active Power Filter; Controllers;

 

Abstract: State-of-the-art, uni-processor linear matrix equation solvers for automatic control computations are investigated and compared for various problem sizes. Generalpurpose SLICOT solvers are the most efficient ones for small-size problems, but they cannot compete for larger problems with specialized solvers designed for certain problem classes.

Keywords: Computer-aided control system design, Large-scale systems, Linear control systems, Lyapunov equation, Numerical algorithms, Numerical solutions

 

Abstract: This paper describes the open-loop control of a stepper motors. Bipolar stepper motors can be driven with an L297, an L298N bridge driver and very few external components. With an L298N this configuration drives motors with winding currents up to 2.5A. If very high powers are required an equivalent circuit made with discrete transistors replaces the bridge driver. Together these two chips form a complete microprocessor-to-stepper motor interface. The command signals for the controller L297 are generated through an IBM-PC486 interface. It was developed an open-loop command program written in BorlandC programming language.

Keywords: Stepper Motor, Stepper Motor Controller, H-Bridge Driver, PWM Chopper, Open-Loop Control.

 

Abstract: The componentwise stability is a special type of asymptotic stability, which incorporates the positive invariance of certain time-dependent rectangular sets with respect to the state space trajectories. The paper develops the analysis of componentwise stability for discrete-time Bidirectional Associative Memory (BAM) neural networks with interval type parameters, providing criteria that allow monitoring the evolution of each state-space variable towards the equilibrium point. These criteria are formulated in terms of Schur stability of a test matrix adequately built from the intervals expressing the parameter uncertainties. Our approach represents a refinement of the classical results in stability theory, since the time-dependence of the considered invariant sets makes it possible to give a qualitative characterization of the dynamics at the level of the state vector components.

Keywords: stability analysis, neural networks, discrete-time systems, nonlinear systems.

 

Abstract: This paper presents a comparative analysis of the behavior of coaxial and frontal couplings – with permanent magnets – in high temperature environments specific to iron and steel industry. The comparative analysis is made at the level of the specific forces developed in the most difficult environments. The maximum temperature was limited for reasons of thermal stability of the Nd-Fe-B permanent magnets. In this context it was studied, by the help of the PDE-ase soft that uses the finite element method, the way magnetic induction modifies, the specific forces developed and the distribution of temperature within the coaxial and frontal couplers with permanent magnets, for variations of the distance between the magnets (air gap) within the limits 2-20 mm.

Keywords: Permanent magnets, permanent magnet couplings.

 

Abstract: The aim of this paper is to present a brief analysis of recent results considering human respiratory mechanics. The final purpose of the investigation is to provide a fast method for identification of airway mechanics, in order to assist the medical staff in obtaining a diagnosis of the patient within the context of performing routine evaluation of the respiratory function. Considerations are made with respect to the future potential of the method as a screening technique on a large number of populations.

Keywords: signal processing, spectral analysis, amplitude modulation, demodulation, filter design, respiratory mechanics, forced oscillations.

 

Abstract: This paper presents a recommender system for textual documents taken from web (given as bookmarks). The system uses for classification a combination of content, event and collaborative filters and for recommendation a modified Pearson-r algorithm. It uses implicit and explicit feedback for evaluating documents.

Keywords: information systems, information analysis, algorithms, machine learning, agents

 

Abstract: The ability to switch between different Database Management Systems (DBMS) is a requirement for many database applications in which effort was invested by many researchers. The main obstacle is the non-uniformity across vendors of the SQL language, the de-facto standard in the industry. Also, an application that maps between an object-oriented application and a relation database needs to be designed in a proper way, in order to achieve the required level of performance and maintainability. This paper presents, extends and further details the Vendor-Independent Database Application (VIDA) framework, initially proposed by us in [9]. The proposed VIDA architecture is described in-depth, based on our practice and experience in this field. The design decisions are presented along with supporting arguments. The VIDA architecture presented here aims to fully decouple the application both from the query language and from the database access technology, providing a uniform view of the database. The problems encountered, both during design and implementation, are presented along with their solutions. Also, the available data access technologies and languages are surveyed and their conformity with a standard is debated.
Keywords: database access layer, DBMS, design patterns, SQL standard, vendorindependence.

 

Abstract: This paper presents a method to find energy-efficient motion path planning avoiding obstacles and obeying constraints. To allow for real-time computation, like human strategy, a path is not completely planned before motion. A motion planning module establish the intermediate positions and velocities points of moving object between starting and goal position. A new segment of total path is computed at each time step between each intermediate points, over a limited horizon. The control signals for torque, speed and position calculated between two states of a planar mechanism are applied in a feed-forward manner to motors drive controllers. There are several experimental results, which confirm the specified performances of the motion control system.
Keywords: Optimal path planning, Trajectory optimisation, Fixed arrival time, Feedforward control, PM synchronous motor drive

 

Abstract: This paper introduces a synthesis methodology for active elements within systems that uses frequency response function as a basis for describing required behavior. The method is applicable in the design of a new system or in the retrofit of an existing system in which an active element is required or desired. The two basis principles of bond graph modeling are the “reticulation principle” which decomposes a physical into elemental physical laws represented as network elements interacting through ports and the “power postulate” which assembles the complete model through a network of power flows representing the exchange of energy between the elements. Moreover the bond graph model leads to a rigorous definitions of the structure of the associated dynamical equations.
Keywords: bond graph, active element, reticulation principle, power postulate.

 

Abstract: Cellular neural networks (CNNs) are recurrent artificial neural networks. Due to their cyclic connections and to the neurons’ nonlinear activation functions, recurrent neural networks are nonlinear dynamic systems, which display stable and unstable fixed points, limit cycles and chaotic behavior. Since the field of neural networks is still a young one, improving the stability conditions for such systems is an obvious and quasipermanent task. This paper focuses on CNNs affected by time delays. We are interested to obtain sufficient conditions for the asymptotical stability of a cellular neural network with time delay feedback and zero control templates. For this purpose we shall use a method suggested by Malkin (1952), where the “exact” Liapunov-Krasovskii functional will be constructed according the procedure proposed by Kharitonov (2001) for stability analysis of uncertain linear time delay systems.
Keywords: cellular neural network, time delays, “exact” Liapunov-Krasovskii functional, absolute stability

 

Abstract: In existed plants with minimum equipment to automatic control it is necessary to increase the safety control by using digital equipment for modelling and control using modern methods for simulation and control. It is necessary to improve the methods for early detection of process and equipment faults. The stabilization problem of steam superheaters is considered. For this goal, are compared three kinds of mathematical models and a suitable model for superheater is given, that highlight the transport delays.

Keywords: modelling, simulation, superheater, transport delays, interconnected systems.

 

Abstract: The paper is a decision – support application which design and use two fuzzy models to estimation an electrical energy tariff, as it to be sell at consumers. The fuzzy tariff estimation model integrate not only the S.C Electrica S.A. rate position, but and some constraints/ compulsions of National Authority of Settlements from Energy (NASE), beginning with 1999, in this transition period from Romania. The paper not refer to a price concrete case (internal tariff used in certain year, production price, transport price, distribution price, spot price, or an external price to be sold electrical energy – EE, etc). The paper shows how, by changing the parameters of S.C Electrica S.A and NASE, it is possible to can perform sensitivity tests on the tariff function model until we obtain an acceptable price. Much more: the two fuzzy models use different rules (conservative and aggressive, with hedge operators, respectively) for pricing. Finally, the paper not finished all fuzzy possibilities (rules) which can influences the expected value of a some EE tariff but, can create a discussion base about the way of approximate/ fuzzy reasoning, as a decision-support application to find a new EE price.

Keywords: fuzzy models