The volume 2003

Table of Contents

A. FILIPESCU, L. DUGARD, J. M. DION: Flexible Joints Robotic Manipulator Control By Adaptive Gain Smooth Sliding Observer-Controller
Abstract   Full Text

Robin DE KEYSER, Clara Mihaela IONESCU: The Disturbance Model In Model Based Predictive Control
Abstract   Full Text

Clara Mihaela IONESCU, Robin DE KEYSER: A Novel Parametric Model For The Human Respiratory System
Abstract   Full Text

Alexandre DOLGUI, Nikolay N. GUSCHINSKY, Genrikh M. LEVIN: Decomposition Methods To Optimise The Structure And Parameters Of Transfer Line With Parallel And Sequential Machining
Abstract   Full Text

Nicolae PARASCHIV , Ciprian VLASCEANU: Automatic Processing Of Radar Images For Electronic River Chart Generation In ECDIS Format
Abstract   Full Text

Cornelia TUDORIE: Vague Criteria In Relational Database Queries
Abstract   Full Text

Marian GAICEANU, Emil ROSU: A Simple Load Power Estimator For Quasi-Direct AC-AC Converter System
Abstract   Full Text

Dorel AIORDACHIOAIE: Building Similarity Maps Of The Environment Using SONAR Information For The Navigation Of The Mobile Robots
Abstract   Full Text

Dorel AIORDACHIOAIE: On Estimation Of The Orientation Of Mobile Robots Using Turning Functions And SONAR Information
Abstract   Full Text

Radu BELEA, Liviu BELDIMAN: A New Method Of Gene Coding For A Genetic Algorithm Designed For Parametric Optimization
Abstract   Full Text

Radu BELEA, Razvan SOLEA: The Parametric Identification Of A Stationary Process
Abstract   Full Text

Viorel NICOLAU: The Influence Of The Ship's Steering Machine Over Yaw And Roll Motions
Abstract   Full Text

Oancea DANIEL: Structure Of Management Information In SNMP
Abstract   Full Text

Ion VONCILA, Cristian MUNTEANU, Razvan BUHOSU, Marcel OANCA: Analysis Of Functional Stability Of The Triphased Asynchronous Generator Used In Conversion Systems Of A Eolian Energy Into Electric Energy
Abstract   Full Text

 

 

A. FILIPESCU, L. DUGARD, J. M. DION: Flexible Joints Robotic Manipulator Control By Adaptive Gain Smooth Sliding Observer-Controller

Abstract: An adaptive gain sliding observer for uncertain parameter nonlinear systems together with an adaptive gain sliding controller is proposed in this paper. It considered nonlinear, SISO affine systems, with uncertainties in steady-state functions and parameters. A further parameter term, adaptively updated, has been introduced in steady state space model of the controlled system, in order to obtain useful information despite fault detection and isolation. By using of the sliding observer with adaptive gain, the robustness to uncertainties is increased and the parameters adaptively updated can provide useful information in fault detection. Also, the state estimation error is bounded accordingly with bound limits of the uncertainties. The both of them, the sliding adaptive observer and sliding controller are designed to fulfill the attractiveness condition of its corresponding switching surface. An application to a single arm with flexible joint robot is presented. In order to alleviate chattering, a parameterized tangent hyperbolic has been used as switching function, instead of pure relay one, to the observer and the controller. Also, the gains of the switching functions, to the sliding observer and sliding controller are adaptively updated depending of estimation error and tracking error, respectively. By the using adaptive gains, the transient and tracking response can be improved.

Keywords:sliding adaptive observer-controller, nonlinear systems, flexible joint robots.

 



Robin DE KEYSER, Clara Mihaela IONESCU: The Disturbance Model In Model Based Predictive Control

Abstract: Model Based Predictive Control (MBPC) is a control methodology which uses a process model on-line in the control computer; this model is used for calculating output predictions and optimizing control actions. The importance of the system model has been generally recognized, but less attention has been paid to the role of the disturbance model. In this paper the importance of the disturbance model is indicated with respect to the EPSAC approach to MBPC. To illustrate this importance, an example of this advanced control methodology applied to a typical mechatronic system is presented, to compare the performances obtained by using different disturbance models. It clearly shows the benefits of using an ‘intelligent’ disturbance model instead of the ‘default’ model generally adopted in practice.

Keywords: disturbance model, disturbance rejection, mechatronics, model, prediction, predictive control.

 



Clara Mihaela IONESCU, Robin DE KEYSER: A Novel Parametric Model For The Human Respiratory System


Abstract: The purpose of this work is to present some recent results in an ongoing research project between Ghent University and Chess Medical Technology Company Belgium. The overall aim of the project is to provide a fast method for identification of the human respiratory system in order to allow for an instantaneously diagnosis of the patient by the medical staff. A novel parametric model of the human respiratory system as well as the obtained experimental results is presented in this paper. A prototype apparatus developed by the company, based on the forced oscillation technique is used to record experimental data from 4 patients in this paper. Signal processing is based on spectral analysis and is followed by the parametric identification of a non-linear mechanistic model. The parametric model is equivalent to the structure of a simple electrical RLC-circuit, containing a non-linear capacitor. These parameters have a useful and easy-to-interpret physical meaning for the medical staff members.

Keywords: respiratory system, respiratory mechanics, biomedical modelling, optimisation, non-linear model, forced oscillation technique.

 



Alexandre DOLGUI, Nikolay N. GUSCHINSKY, Genrikh M. LEVIN: Decomposition Methods To Optimise The Structure And Parameters Of Transfer Line With Parallel And Sequential Machining


Abstract: The paper is devoted to a preliminary design problem of paced automatic transfer lines. At this design stage, the following decisions are to be made: the partitioning of the given set of operations into subsets performed by one spindle head; the grouping of the spindle heads into workstations, the choice of operating modes for each spindle head. The aim is to minimise the line life cycle cost per part under the given productivity and technological constraints. The paper focuses on a mathematical model of the problem and methods to solve it. The model is formulated in terms of mixed (discrete and non-linear) programming. For solving the optimisation problem, a special decomposition scheme is proposed, which is based on parametric decomposition technique as well as on Branch-and-Bound and multi-criteria shortest path algorithms.

Keywords: Production systems, Optimisation, Decomposition methods, Graph theory.

 



Nicolae PARASCHIV , Ciprian VLASCEANU: Automatic Processing Of Radar Images For Electronic River Chart Generation In ECDIS Format


Abstract: Presenting the navigation environment in electronic format – ECDIS – triggers a major change of the classic method of cartography and raises up the need to approach a way of producing the charts in vector-like format. The present paper is intended to describe a way of processing information (provided by a RADAR system and a GPS receiver), using Kalman filter algorithms and the elements form graph theory, to provide a rough form of an electronic chart. This can be completed afterwards by adding further information so that the chart can become totally compatible with ECDIS standard and can be used in automatic or aided inland navigation.

Keywords: inland navigation, electronic vector-like charts, ECDIS, RADAR, GPS precision, image processing, Kalman filter, graph based algorithm.

 



Cornelia TUDORIE: Vague Criteria In Relational Database Queries


Abstract: The most accessible interfaces querying relational database should allow vague terms included in selection criteria. The gradual property stands for the simplest vague selection criterion, but more categories of vague terms can be identified in a natural expression of a query. All of them can be modelled using fuzzy sets theory. A complete general syntax of a vague criterion of database selection will be concluded. Appropriate transformation or operations are defined in order to compute the degree of satisfaction for the vague criteria containing fuzzy terms.

Keywords: Artificial Intelligence, Database, Flexible Queries, Fuzzy Logic.

 



Marian GAICEANU, Emil ROSU: A Simple Load Power Estimator For Quasi-Direct AC-AC Converter System


Abstract: In this paper a simple load power estimator for the three-phase quasi-direct acac converter system is reported. Since the ac-ac converter control by means of pulsewidth modulation (PWM) is based on the power balance concept, its load power should be known. Two control boards, based on the dSMC (digital Smart Motion Controller) 30 MIPS 32-bit fixed-point digital signal processor (DSP), were involved in the ac-ac system driving. By using the power balance control, the DC link voltage variation at the load changes can be reduced. In this way a small DC link capacitor is required to handle the dc voltage error control. The feed-forward (Sul and Lipo, 1990) current component provides fast correction of the reference control to load power variation. In order to obtain the feed-forward current component, the load power must to be known. In this paper the load power is estimated from the dc link, indirectly, through a dc load current estimator. In this way the author overcomes the use of the serial communication between control boards (Gaiceanu, 2004) in order to deliver the load power information from the inverter side. The load current estimator is based on the DC link voltage and on the load current of the supply converter. This method presents certain advantages instead of using measured method, which requires a low pass filter: no time delay, the feed-forward current component has no ripple, no additional hardware, and more fast control response. Through simulation and experimental results the performances of the proposed load current estimator scheme are demonstrated.

Keywords: current estimator, PWM ac-ac converter, power balance, load feed-forward, digital control, synchronous current controller, rotor field oriented control.

 



Dorel AIORDACHIOAIE: Building Similarity Maps Of The Environment Using SONAR Information For The Navigation Of The Mobile Robots


Abstract: The objective of the work is to present a representation called similarity map based on some results in the evaluation of the SONAR system of a mobile robot. As environment a corner of our lab it is considered. Based on some reference positions, where the robot is making a complete rotation, some test positions are considered with the task of recognition of the environment, in order to be able to recognize the position. Using similarity measures based on Euclidian distance, similarities maps are defined and estimated. The results are useful in defining complex strategies of navigation using SONAR systems.

Keywords: Similarity measures, Pattern Recognition, Signal Processing, SONAR, Mobile Robots.

 



Dorel AIORDACHIOAIE: On Estimation Of The Orientation Of Mobile Robots Using Turning Functions And SONAR Information


Abstract: SONAR systems are widely used by some artificial objects, e.g. robots, and by animals, e.g. bats, for navigation and pattern recognition. The objective of this paper is to present a solution on the estimation of the orientation in the environment of mobile robots, in the context of navigation, using the turning function approach. The results are shown to be accurate and can be used further in the design of navigation strategies of mobile robots.

Keywords: SONAR, Navigation, Pattern Recognition, Signal Processing, and Turning Functions.

 



Radu BELEA, Liviu BELDIMAN: A New Method Of Gene Coding For A Genetic Algorithm Designed For Parametric Optimization


Abstract: In a parametric optimization problem the genes code the real parameters of the fitness function. There are two coding techniques known under the names of: binary coded genes and real coded genes. The comparison between these two is a controversial subject since the first papers about parametric optimization have appeared. An objective analysis regarding the advantages and disadvantages of the two coding techniques is difficult to be done while different format information is compared. The present paper suggests a gene coding technique that uses the same format for both binary coded genes and for the real coded genes. After unifying the real parameters representation, the next criterion is going to be applied: the differences between the two techniques are statistically measured by the effect of the genetic operators over some random generated fellows.

Keywords: binary coded genes, exploration, exploitation, random initialized genes, uniform crossover, HUX crossover, arithmetic crossover.

 



Radu BELEA, Razvan SOLEA: The Parametric Identification Of A Stationary Process


Abstract: In the problems of identification it is supposed that the process has at least one measurable input size and at least one measurable output size. The identification of a process has three stages: the obtaining of a registration of process measurable sizes; the choice of a proper mathematical model for the process; the extract of the parameter values of the mathematical models from registered data. The parametric identification problem is an optimization problem, in which the best combination of values for the model parameters set is searched. In the paper is presented the parametric identification of a water flow process in a laboratory stand. The identification had the following dims: detailed understanding of how the stand works, finding a new illustrative experiment for the stand, the application of advanced techniques of automat control, and the development of a project of new stand, meant to allow a large variety of experiments.

Keywords: genetic algorithms, fitness function, flow control, level control.

 



Viorel NICOLAU: The Influence Of The Ship's Steering Machine Over Yaw And Roll Motions


Abstract: The steering machine is a nonlinear system, with two important limitations: the maximum rudder angle and rudder rate. Therefore, the commands from yaw and rudder-roll control systems are modified and the expected effect is not always the optimum one. It is important to know the influence of the steering machine, trying to avoid the limitations or to include them into the control law. The goal of this paper is to analyze the steering machine limitations and their influence over yaw and roll motions of the ship. Also, some expert rules are generated, which can be used to implement more efficient control laws.

Keywords: steering machine, autopilot commands, rudder-roll damping system.

 



Oancea DANIEL: Structure Of Management Information In SNMP


Abstract: In this article we present the Structure of Management Information from SNMP, for all three versions of SNMP, as well as the main differences between them. In the first part, two version of SNMP are presented: version 1, version 2; and in the last part the third version, that uses a security model for information protection, is presented.

Keywords: SMTP

 



Ion VONCILA, Cristian MUNTEANU, Razvan BUHOSU, Marcel OANCA: Analysis Of Functional Stability Of The Triphased Asynchronous Generator Used In Conversion Systems Of A Eolian Energy Into Electric Energy


Abstract: This paper presents a study of the influence of the main perturbation agent over the functional stability of the triphased asynchronous generator (for the two alternative: with coiled and short circuit rotor), used for the conversion systems from a eolian energy into electric energy.

Keywords: triphased asynchronous generator.