WSEAS CONFERENCES. WSEAS, Unifying the Science

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 Volume 4, 2009
Print ISSN: 1991-8763
E-ISSN: 2224-2856








Issue 1, Volume 4, January 2009

Title of the Paper:  Metal Chamber Temperature Control by Using Fuzzy PID Gain Auto-tuning Strategy


Authors: Shiuh-Jer Huang, Yi-Ho Lo

Abstract: Although PID control scheme is widely employed in industrial control systems, it is hard to search the model-free appropriate control gains for achieving good dynamic performance. The selected constant PID control gains can not achieve consistent control accuracy for different temperature setting points or testing runs. In addition, the temperature control system has nonlinear time-delay, time-varying, slow response speed and one-way control input characteristics, it is also difficult to accurately estimate the dynamic model for designing a model-based general purpose temperature controller to achieve good control performance. Recently, temperature is become an important production control parameter in chemical and semiconductor industry. How to design an appropriate gains auto-tuning control strategy for achieving accurate temperature control accuracy has become an interesting research topic. Here two model-free auto-tuning PID and fuzzy PID control strategies are introduced to design a general temperature controller for different plants. The designed temperature control plants have heater control phase only without cooling control function. The experimental results show that these control schemes can obtain reasonable control performance. The steady state error of the step input response is less than 0.2 without overshoot. The setting point dynamic response behaviour is better than that of the model-based IMC-PID due to the modelling uncertainty and modelling error.

Keywords: Temperature control, gain auto-tuning, fuzzy PID and one-way control input

Title of the Paper:  On the Modelling and Controller Design for the Outpouring Phase of the Pouring Process


Authors: M. P. Tzamtzi, F. N. Koumboulis, M. G. Skarpetis

Abstract: The present work contributes towards modeling and control of the outpouring phase of a pouring process, where the liquid container is carried by a robotic manipulator. The dynamics of the liquid motion are approximated by the well-known pendulum-type model, where the length and the mass of the pendulum vary with time due to liquid outpouring. The dynamics of the liquid transfer structure, including the carrying manipulator, the container and the liquid, are approximated by the dynamics of a robotic structure that incorporates virtual prismatic joints and corresponding weightless links to represent variations of the liquid level and corresponding variations of the pendulum length within the tank. The performance of a two stage control design scheme on the control of liquid outpouring and the suppression of liquid sloshing during the outpouring phase of the pouring process is studied for the derived model using simulation results. The designed scheme combines a partial inverse dynamics controller with a PID controller, tuned with the use of a “metaheuristic” search algorithm. Both controllers have been designed for a nominal model, ignoring the loss of liquid’s mass due to outpouring.

Keywords: Robotic applications, Robot Control, Nonlinear Control, Pouring Process, Sloshing Control

Title of the Paper:  An Application of Fuzzy Delphi and Fuzzy AHP for Multi-criteria Evaluation on Bicycle Industry Supply Chains


Authors: Jao-Hong Cheng, Chih-Huei Tang

Abstract: Under global saving energy and carbon wave and increasing incomes, the bicycle not only is a traditional transportation but also has become a tour and sport tool. Concerning the bicycle industry, the prior researches worked on analyzing bicycle tire suppliers and focused on the business strategy and cost analysis. Therefore, the purpose of this study is to identify critical factors related to the bicycle supplier selection. Primary criteria to evaluate supplier selection is obtained by the literatures survey and applying fuzzy Delphi method (FDM), and then fuzzy analytic hierarchy process (FAHP) is employed to calculate the weights of these criteria, so as to build the fuzzy multi-criteria model of bicycle supplier selection. The results indicate a greatest weight on the dimension of bicycle supplier selection, and four critical evaluation criteria related to bicycle supplier selection are delivery time, service quality, optimum price, and product quality.

Keywords: Bicycle Industry, Supply Chain, Analytic Hierarchy Process (AHP), Fuzzy Delphi Method (FDM), Fuzzy Analytic Hierarchy Process (FAHP)

Title of the Paper:  The Structure of Modular Walking Robot MERO Displacement Systems, Support of the Heavy Load Transportation


Authors: Ion Ion, Luige Vladareanu, Ion Simionescu, Aurelian Vasile

Abstract: The modular constructions of the walking robots led to a more suppleness and very good adaptation to any terrain surface. Some of the most significant components of the walking robots are the mechanisms of the displacement systems. The design of the leg mechanisms implies the solving of several problems regarding the static stability, the forces distribution, balancing of the gravitational forces in order to diminish the power consumption, optimization of the foot sole shape, optimization of the kinematic dimensions of the leg etc The advantages of legged system for off-road have been gradually recognised. One of the most important advantages is mobility. The Modular walking robots represent a special category of robots, characterized by having the power source embarked on the platform. The weight of this source is an important part of the total charge that the walking robot must transport. That is the reason why the walking system must be designed so that the mechanical work necessary for displacement, or the highest power necessary for act it, should be minimal A modular walking robot can traverses most natural terrain. Walking robots better protect the environment, as their contact to the ground is discrete, which considerably diminishes the area underwent to crushing; the robot’s weight can be optimally distributed all over the supporting surface, by controlling the forces. Altering the distance to the ground, the robot can pass over young trees or other vegetation, growing in the passage area.

Keywords: Modular Walking Robot, Static Balancing, Shifting System ,Legs, Stability margin

Title of the Paper:  Voltage-Dependent Parameter Refinement for Single-phase Induction Motors using Genetic Algorithms


Authors: N. Naewngerndee, T. Kulworawanichpong

Abstract: This paper presents a genetic-based approach to correct the parameters for single-phase induction motors in various supply voltage levels. From conventional tests, electrical (resistances and inductances) and mechanical (moment of inertia and damping coefficient) parameters of the stator and the rotor can be estimated. The set of obtained parameters is able to apply for steady-state performance analyses. In transient states, motor responses generated by these parameters are not met the condition of acceptable accuracy. By some efficient search method incorporate with experimental data, the obtained parameters can be refined to yield the best curve fitting in both transient and steady-state responses. A 0.37-kW, 220 V, 50 Hz single-phase induction motor was used for test to verify the effectiveness of the proposed algorithm. Furthermore, with six different motor supply voltages, voltage-dependent parameters of single-phase induction motors can be established. As a result, the voltage-dependent parameters of the induction motors can be satisfactorily improved to represent the motor dynamic in various supply voltages.

Keywords: Single-phase induction motor, Space-phasor model, Voltage-dependent parameter, Genetic algorithm, Retardation test, blocked-rotor test, No-load test

Title of the Paper:  High Accurate Positioning Technique for AUV


Authors: Tain-Sou Tsay

Abstract: In this paper, a high accurate positioning technique is proposed for autonomous underwater vehicle(AUV). It needs not position correction from Global Position System (GPS) above the sea surface and short- or long-baseline acoustic positioning system(SBL or LBL) under the sea. Two long time experiments gave maximal and average deviations are less than 33.6m and 15.1m; respectively. Position deviations are verified by tracking datum of a long-baseline acoustic position system with post navigation processing datum. These deviations are much less than the tracking range of sonar. High accurate positioning results let vehicles have less supporting from launching vessel and give flexible and mobile operations.

Keywords: Position estimation, Navigation and guidance, Autonomous underwater vehicle

Issue 2, Volume 4, February 2009

Title of the Paper:  Transformation of a Production/assembly Washing Machine Lines into a Lean Manufacturing System


Authors: E. Romano, L. C. Santillo, P. Zoppoli

Abstract: The scope of this work is the complete re-organization of production flow according to the Lean Thinking philosophy for the industrial applications. The complete re-organization implementation of material flow management has been performed through the supermarket sizing which replenishment kanban logic has been adopted. To implement this strategy the goal is to achieve "Interdependent connected Processes" adopting the Pull System methodology in the Just in Time production environment. From the narrow sense the JIT manufacturing philosophy is to produce the right quantity at the right time with the right quantity level. In JIT the production is triggered by a kanban signal, which comes from the costumer order or the master production schedule, the signal then flowing backwards. By implementing JIT concepts in manufacturing, many of the practitioners experience advantages such as shorter lead times, fewer inventories, and higher quality. In the case study, developed in the Whirlpool Europe Naples factory, we have a first stage that consists of sizing the amount of "Kanban reintegration" codes, and the second stage in which we have simulated with ARENA and verified the progress of production flow in the hypothesized system, that has underlined the improvement of the business performances and great flexibility.

Keywords: Pull system, kanban, simulation, supermarket pull, Sequential Learning, pattern production schedule

Title of the Paper:  System Approach to Synthesis, Modeling and Control of Complex Dynamical Systems


Authors: Armen G. Bagdasaryan

Abstract: The basic features of complex dynamical and control systems, including systems having hierarchical structure, are considered. Special attention is paid to the problems of synthesis of dynamical models of complex systems, construction of efficient control models, and to the development of simulation techniques. An approach to the synthesis of dynamic models of complex systems that integrates expert knowledge with the process of modeling is proposed. A set-theoretic model of complex system is defined and briefly analyzed. A mathematical model of complex dynamical system with control, based on aggregate description, is also proposed. The structure of the model is described, and architecture of computer simulation system is presented, requirements to and components of computer simulation systems are analyzed.

Keywords: Systems, complexity, dynamics, modeling, control, simulation, computer simulation system

Title of the Paper:  NN-based Algorithm for Control Valve Stiction Quantification


Authors: H. Zabiri, A. Maulud, N. Omar

Abstract: Control valve stiction is the most commonly found valve problem in the process industry. Quantification of the actual amount of stiction present in a loop is an important step that may help in scheduling the optimum maintenance work for the valves. In this paper, a Neural-network based stiction quantification algorithm is developed. It is shown that the performance of the proposed quantification algorithm is comparable to other method whereby accurate estimation of the stiction amount can be achieved even in the presence of random noise. Its robustness towards external oscillating disturbances is also investigated.

Keywords: Control valve, stiction, neural network, quantification

Title of the Paper:  Petri Nets and Fuzzy Sets in Hybrid Controllers Synthesis: The Discrete-Event Aspect


Authors: Lucien Ngalamou, Leary Myers

Abstract: This paper presents a design approach intended for the modeling and synthesis of discrete-event modules of hybrid controllers by combining a model of computation and a soft computing synthesis approach. The model of computation is based on coloured Petri nets (CPNs) and the soft computing method uses fuzzy logic. The design approach converts Petri net models into their equivalent fuzzy sets for rapid prototyping on embedded controllers or programmable Logic devices. The Petri net model of a discrete-event controller is captured and modeled using DesignCPN software tool whose latest version is called CPNTool. Design/CPN (CPNTool) uses colored Petri nets (CPNs) in model representation. Fuzzy sets generated in the conversion process are compatible inputs (fuzzy sets) to the Xfuzzy software, which is a fuzzy logic software for the design of fuzzy controllers. Xfuzzy can generate equivalent C and VHDL codes from fuzzy sets.

Keywords: Model of computation, coloured Petri nets, soft computing, fuzzy sets, and discrete-event controller

Issue 3, Volume 4, March 2009

Title of the Paper:  Numerical Simulation of a Flexible Plate System for Vibration Control


Authors: A. R. Tavakolpour, I. Z. Mat Darus, M. Mailah

Abstract: This research presents an investigation into the numerical simulation of a flexible thin plate using Finite Difference (FD) and Finite Element (FE). Based on the FD method, an appropriate model of a thin plate was derived and its corresponding natural frequencies were estimated. Then, FE modeling of the plate system was implemented using the ANSYS software and the corresponding modes of vibration were computed by modal analysis. The obtained vibration modes for both models were then evaluated and compared. A number of attempts have been carried out to determine the nodal lines on the plate in order to identify the critical observation points for appropriate locations of the sensors using the FE simulation. Finally, the effectiveness of FD method for real time application was verified by comparative assessment of the obtained natural frequencies with the exact value reported by other researchers. The FD method was found to be the better choice than FE method to model a plate structure for real-time active vibration control.

Keywords: Finite Difference, Finite Element, Flexible Plate, Active Vibration Control, Dynamic Modeling

Title of the Paper:  Space Vector Double Frame Field Oriented Control of Six Phase Induction Motors


Authors: M. Kamari, M. Keramatzadeh, R. Kianinezhad

Abstract: In this paper a new rotor field orientation control of six phase induction machine is proposed. The machine has two three phase windings spatially shifted by 30 electrical degrees. The dynamic model of the machine is based on the three two dimensional orthogonal subspaces. The proposed method uses a simple estimator for identifying rotor flux and its orientation. To eliminate the extra harmonic currents of stator windings that produce losses, space vector PWM technique and double synchronous frame current controller is employed. The simulation results illustrate the validity and efficiency of the proposed method.

Keywords: Six-phase induction machine; Vector control; Space voltage modulation

Title of the Paper:  The Algorithm of Obstacle Avoidance based on Improved Fuzzy Neural Networks Fusion for Exploration Vehicle


Authors: Shunming Li, Jianghui Xin, Weiyan Shang, Shen Huan, Wenqing Xiu

Abstract: In order to improve the vehicle steering stability, and avoid the obstacles fast and accurately, the fuzzy neural networks has been developed, in detail introduced this algorithm control principle. Advance control algorithm usually needs much more prior knowledge and depends on the accuracy model of process. However, fuzzy logic control technology is applied to control the plants having fuzzy, uncertainty, high-order, heavy lag without accurate mathematics model. The neural network has the advantage of self-learning, memory ability, fault-tolerant and parallel processing etc. The back propagation neural network was taken as framework, combining an improved fuzzy control algorithm, to realize the fuzzy-neural control of the exploration vehicle’s navigation. It can use the improved fuzzy theory and neural networks together to form an improved fuzzy neural networks control system. So it can auto pick-up the fuzzy rule and build the subordinate function, it’s self-organizing and self-learning the control knowledge which is needed for steering process and precise obstacle avoidance. The result of simulation analyses indicate that the method proposed in the paper can achieve safe and stability in steering control of obstacle avoidance of exploration vehicle.

Keywords: Fuzzy neural networks, obstacle avoidance, exploration vehicle, steering stability, pattern matching, path planning

Title of the Paper:  Tension Robust Control Strategy Based on Self-Optimizing Algorithm


Authors: Jinbao He, Yongyi He, Shuai Guo, Minglun Fang

Abstract: In tension systems, the main concern is to decouple the tension and velocity in spite of radius variations and other perturbations. To solve this control problem and design the optimal controller, this paper develops a mixed-sensitivity robust H∞ control based on self-optimizing algorithm. First, the modeling of the tension system is presented with relative theorems. Second, a mixed-sensitivity robust H∞ control which reduces the coupling between tension and velocity is compared to PID controller. But the H∞ controller is conservative, the H∞ controller method with parameter fuzzification is introduced. At low velocity, the H∞ control method with parameter fuzzification gets fine results. However, for the high velocity and real time requirements of tension system, the H∞ control method with parameter fuzzification cannot keep the controller optimal always. Therefore the tension robust control strategy based on self-optimizing algorithm is proposed. The controller is optimized by hyper generation GA (HGGA) which reduces computing time. Furthermore, the current error and the change of the error are turned to compensate time delay. In order to test the effectiveness of the proposed algorithms, the tension experiment platform analog system is developed based on DSP (TMS320LF2407A) board. Finally the algorithms in this paper are tested in tension system platform, and the feasibility has been verified.

Keywords: Tension system, robust control, parameter fuzzification, genetic algorithm (GA), hyper generation GA (HGGA), time delay, DSP

Issue 4, Volume 4, April 2009

Title of the Paper:  Pseudo-Equivalence of Fuzzy PID Controllers


Authors: Constantin Volosencu

Abstract: This paper presents a pseudo-equivalence of digital fuzzy PID controllers with linear PID controllers in the continuous time domain. Transfer functions and equivalence relations between controller’s parameters are obtained for the common structures of the fuzzy PID controllers. The pseudo-equivalence is made using a graphic analytical analysis based on the input-output transfer characteristics of the fuzzy block, the linear characteristic of the fuzzy block around the origin and the usage of the gain in origin obtained as an origin limit of the variable gain of the fuzzy block. An algorithm of equivalence is presented. The paper presents a unitary theory, which may be applied to the most general fuzzy PID controllers, developed using all kind of membership functions, rule bases, inference methods and defuzzification methods. The term “pseudoequivalence” is emphasized because there is no straight equivalence between the non-linear fuzzy controllers and the linear PID controllers. A case study of a control system using linear and fuzzy controllers is presented. The action mode of the fuzzy controller is analyzed. Based on the transient characteristics a comparison analyses is done. Better control quality criteria are demonstrated for control systems using fuzzy controllers.

Keywords: Fuzzy logic, control systems, PID controllers

Title of the Paper:  Identification of the De-synchronization, Synchronization and Forced Oscillation Phenomenon of a Nonlinear System


Authors: Marius-Constantin Popescu, Onisifor Olaru, Valentina Balas

Abstract: The phenomena of de-synchronization, synchronization, and forced oscillation has been investigation using describing function theory for a two input and two output nonlinear system containing saturation-type nonlinearities and subjected to high-frequency deterministic signal for the purpose of limit cycle quenching. The analytical results have been compared with the results of digital simulation Matlab-Simulink for a typical example varying the nonlinear element.

Keywords: Signal stabilization, Limit cycle, Forced oscillation, Dither, Saturation

Title of the Paper:  An Approach to Fault Diagnosis of Rolling Bearings


Authors: A. A. Roque, T. A. N. Silva, J. M. F. Calado, J. C. Q. Dias

Abstract: The present paper aims to demonstrate why usually when theoretical mathematical models are used to compute the frequencies corresponding to a faulty rolling bearing a deviation is obtained between the computed values and the real frequencies emitted by such a device. A laboratory rolling bearing test ring has been developed to perform the current studies. From the obtained results we highlight the impact of the cage rotation frequency on the referred deviation of measured values from the theoretical ones.

Keywords: Fault detection, Fault isolation, Fault diagnosis, Rolling bearing, Condition based maintenance

Title of the Paper:  Dynamics and Flight control of the UAV Formations


Authors: Teodor-Viorel Chelaru, Valentin Pana, Adrian Chelaru

Abstract: The purpose of this paper is to describe the flight of an Unmanned Aerial Vehicles (UAV) formation by using a 6 degrees of freedom (6 DOF) models. The problem of flight formation will be approached in a simple manner, by using a 3 DOF models, as well as using the complex equations that describe the movement of the 6 DOF for UAV. This theoretical development allows us to define a control structure based on direct commands, which is useful in practical applications. The work will present and analyze the calculus results for each developed solution. The novelty of this paper consists in the definition and testing of some practical solutions for an algorithm that can control an UAV formation. This algorithm allows decrypting the flight of a single UAV, as well as the entire formation. The conclusions will focus the practical possibility of implementing such algorithm on a UAV formation.

Keywords: UAV, Flight, Formation, Dynamic, Control

Issue 5, Volume 4, May 2009

Title of the Paper:  Control of a Radiative Furnace under Precise and Uncertainty Conditions


Authors: Peyman Nazarian

Abstract: This paper discusses the control of a radiative furnace under precise and imprecise modeling. Regarding nonlinearity nature of the process, in the precise case, feedback linearization technique is applied to the furnace and under uncertainty conditions, sliding mode control is used. The conditions are completely practical and have gained from an industrial process.

Keywords: Feedback Linearization – Radiation – Furnace – Uncertainty – Sliding Mode Control

Title of the Paper:  A Unified Approach for Sensitivity Design of PID Controllers in the Frequency Domain


Authors: Tooran Emami, John M. Watkins

Abstract: In this paper a graphical technique is introduced for finding all continuous-time and discrete-time proportional integral derivative (PID) controllers that satisfy an H? sensitivity constraint of an arbitrary order transfer function with time delay. These problems can be solved by finding all achievable PID controllers that simultaneously stabilize the closed-loop characteristic polynomial and satisfy constraints defined by a set of related complex polynomials. A key advantage of this procedure is that it only depends on the frequency response of the system. The delta operator is used to describe the controllers, because it not only possesses numerical properties superior to the discrete-time shift operator, but also converges to the continuous-time controller as the sampling period approaches zero. A unified approach allows us to use the same procedure for discrete-time and continuoustime H? sensitivity design of PID controllers.

Keywords: Sensitivity design, frequency response, delta domain, PID controllers, and time delay

Title of the Paper:  Robust Performance Characterization of PID Controllers in the Frequency Domain


Authors: Tooran Emami, John M. Watkins

Abstract: In this paper a method is introduced for finding all proportional integral derivative (PID) controllers that satisfy a robust performance constraint for a given single-input-single-output transfer function of any order with time-delay. This problem can be solved by finding all achievable PID controllers that simultaneously stabilize the closed-loop characteristic polynomial and satisfy constraints defined by a set of related complex polynomials. A key advantage of this procedure is that it only depends on the frequency response of the system and does not require the plant transfer function coefficients. If the plant transfer function is given, the procedure is still appropriate. The ability to include the time-delay in the nominal model of the system will often allow for designs with reduced conservativeness in the plant uncertainty and an increase in size of the set of all PID controllers that robustly meet the performance requirements.

Keywords: Robust performance, frequency response, PID controllers, and time-delay

Issue 6, Volume 4, June 2009

Title of the Paper:  Multiple Method Switching System for Electrical Appliances using Programmable Logic Controller


Authors: S. K. Subramaniam, S. H. Husin, S. A. Anas, A. H. Hamidon

Abstract: Smart switching system is designed for smart home control applications. The system uses real time programmable logic controller (PLC) for switching the electrical appliances. Electrical appliance is a part of our daily needs for mankind. When such needs are in a very high demand, the user’s requirement is also increasing to access their electrical appliances in a more flexible way and also safer to use. The system is capable of switching any electrical appliances manually, preprogrammed and remotely. The most common practice in our daily life’s is manual switching. Manual switching is done with human access according to instant needs. The second method in this system is preprogramming method which allows the users to program the usage of certain electrical appliances in advance or repetitively. Such function can be used on daily, weekly, monthly and even yearly basis based on the requirements of the user. The third method in this system is remote switching where the users are capable of sending Short Messaging System (SMS) to switch ON and OFF their electrical appliances using mobile phones. Global System for Mobile Communication Modulator and Demodulator (GSM Modem) enables SMS commands to be received to the PLC. The applications of technology have seen many new intelligent systems overwriting the conventional method to ease human life in many ways. Many systems are designed to be flexible for the users and enable them to communicate for the latest status of their electrical appliances at any time. Such applications will be practical and benefits for both the domestic and industrial users from various level of electrical applications without boundaries.

Keywords: Smart home, smart switching system, intelligent controller, Short Messaging System, Programmable Logic Controller

Title of the Paper:  Speed Control of Double Stator Synchronous Machine Supplied by two Independent Voltage Source Inverters


Authors: Nazih Moubayed

Abstract: In high power applications, power division methods for AC high power converters and machines are used. The rated power of the elementary converters and/or machines becomes lower when the number of converters and/or machines increases. Therefore, power switches with high switching frequency can be used. Then, the current and torque ripples would have theoretically lower amplitude. The speed control of a double stator synchronous machine supplied by two independent voltage source inverters, which is an application of power division, is studied in this paper. After presenting the system under consideration, three strategies of current control are treated. The speed control method is also discussed.

Keywords: Multi-converter, double stator machine, power division, current and speed control

Title of the Paper:  Using the Black-Box Approach with Machine Learning Methods in Order to Improve Job Scheduling in GRID Environments


Authors: Daniel Vladusic

Abstract: This article focuses on mapping jobs to resources with use of off-the-shelf machine learning methods. The machine learning methods are used in the black-box manner, having a wide variety of parameters for internal cross validation. In the article we focus on two sets of experiments, both constructed with a goal of congesting the system. In the first part, the machine learning methods are used as assistants for the base resource selection algorithms, while in the second part, they are used to directly select the resource for job execution. We set up two experiments with different objectives. In the first experiment, the objective was to maximize the number of jobs finished within the deadline, while in the second experiment, the objective was to minimize the job tardiness. Finally, in the first part we were changing resource selections of simple job dispatching algorithms, while in the second part, we were employing the optimization scheme of the ALEA algorithm [15]. The results show that even with a such black-box approach of the off-the-shelf machine learning methods, we can achieve improvements or at least get comparable results.

Keywords: Scheduling, distributed systems, GRID, dispatching jobs in GRIDs, machine learning

Issue 7, Volume 4, July 2009

Title of the Paper:  Applying Intelligent Fuzzy Control to Reduce Hysteresis Effect of Force Actuator in a SPM


Authors: Jium-Ming Lin, Po-Kuang Chang

Abstract: This research is to use fuzzy controller to eliminate hysteresis effect of a force actuator for a Scanning Probe Microscope (SPM). This improvement has been verified by MATLAB simulation and practical implementation to reduce the hysteresis effect of the force actuator. Comparisons with two previous designs with and without Linear Velocity Transducer (LVT) for inner-loop feedback compensation are also made. Thus the new system design is cheaper and valuable.

Keywords: SPM, LVT, LVDT, Fuzzy controller, PI compensator, Force actuator, Hysteresis effect

Title of the Paper:  Extended Static Output Feedback: An H2-H1 Control Setting


Authors: Addison Rios-Bolivar, Francklin Rivas, Gloria Mousalli

Abstract: This contribution aims the problem about controller synthesis in H2 and H1 for linear time invariant systems (LTI), by means of the extended static feedback of the output. The method consists of designing feedback gains for the injection of the output and its derivatives, which corresponds to the control signal. Conditions for the existence of such controllers are established. The stabilization problem is formulated in the context of linear matrix inequalities (LMI). Multiobjective Performance Indices are also considered

Keywords: Static Output Feedback, Robust Control, LMI, Polytopical Uncertainty

Title of the Paper:  Application of Braking/Traction Control Systems to the Scaled Active Steering Testbed in the Railway Vehicle


Authors: Min-Soo Kim, Hyun-Moo Hur

Abstract: Active steering system of railway vehicles has proven its ability to bridge the gap between stability and curve friendliness. Generally scaled railway vehicles were developed to reproduce the fundamental dynamic behavior of the full size railway vehicle in laboratory conditions. This paper describes the design of the braking/traction control systems as a part of a 1/5 scaled railway vehicle for active steering testbed which is to alleviate wheel/rail contact forces and to decrease wheel/rail wear. This system consists of two steering actuators, a steering controller, and various sensor systems to detect lateral displacement, vibration, track curvature, and so on. The control strategy of the braking/traction is founded on the velocity difference of two axle speed of the driving bogie. Running test results of 1/5 scaled active steering vehicle on the curved track show that the proposed braking/traction control systems has good performance.

Keywords: Braking/Traction Control Systems, Active Steering, Railway Vehicle, Scaled Model, Testbed

Title of the Paper:  Fuzzy Controller Design with the Degree of Non-uniformity for the Scaled Active Steering Testbed in the Railway Vehicle


Authors: Min-Soo Kim

Abstract: In urban transit systems, rail passenger vehicles are often required to negotiate tight curves. Running curve railway, the wheelsets of conventional vehicles generally misalign radically with the track increasing wheel/rail contact forces and resulting in increased wheel and rail wear, outbreak of squeal noise, fuel consumption, and risk of derailment. To solve these problems, modified suspension system designs, application for alternate wheel profiles, active and semi-active steering techniques have been proposed. Active steering system has proven its ability to bridge the gap between stability and curve friendliness. This paper presents a technique for improving the performance of active steering fuzzy control systems by adequately changing the widths of triangular fuzzy membership functions. Experiment results show that the proposed fuzzy controller robustly yields good performance comparing with conventional controller.

Keywords: Fuzzy Controller, Degree of Nonuniformity, Active Steering, Railway Vehicle, Scaled Model

Title of the Paper:  Active Cord Mechanism (ACM) Controller for Biologically Inspired Robots Designed with Frequency Response Approach


Authors: Anubhuti Saha, R. P. Chatterjee, Sarbari Datta

Abstract: Multi-segmented robots earn some basic advantages of assembling and disassembling of their body parts and different types of movement in a single body structure. Snake robots can manifolds four types of motion in the surface level using different transfer function. The main task is to derive the transfer function of each segment that can control the snake body to navigate with Active Cord Mechanism. Lead compensators are subject to improve the speed of response of the snake body while lag compensators optimize its errors in deviation while obstacle avoidance. A composite of lag-lead compensator is discussed and examined for SUPRA Institutional Serpentine robot to be employed in a coal mine for disaster management. The side winding movement is taken into consideration and wireless control of snake robot is a matter of importance. This paper holds a discussion over the controller design procedure using frequency response approach and shows a comparison between the lead-lag and only lag compensators with their transient and impulse responses. Finally results are shown to support the stability analysis of the designed control system.

Keywords: ACM, snake robot, frequency domain approach, lag-lead compensator

Title of the Paper:  Modular System for Process Control Testing


Authors: Ioana Fagarasan, S. St. Iliescu, Iulia Dumitru, Nicoleta Arghira, I. Bucur

Abstract: A modular system for processes simulator and control diagram implementation can replace a vast number of expensive systems used to simulate, to design and to test the programming of programmable logical control (PLC) systems graphically and practically. Different processes are simulated and associated with different types of control application and with different complexity factors in order to develop control algorithms and implement them into the PLC unit. The process and control simulator is hardware and software intergraded system for multifunctional educational platforms that enables training and practical work. The system’s modularity allows an easy development of the system and can be use in future development by adding FPGA (Field-Programmable Gate Array) components.

Keywords: Electrical process, mechanical process, system simulator, control system design, PLC

Title of the Paper:  Evolutionary Computation for Minimizing Makespan on Identical Machines with Mold Constraints


Authors: Tzung-Pei Hong, Pei-Chen Sun, Sheng-Shin Jou

Abstract: This paper focuses on minimizing makespan of identical-machines scheduling problems with mold constraints. In this kind of problems, jobs are non-preemptive with mold constraints and several identical machines are available. Feasible solutions are randomly generated and evolved by the proposed approach and an adjustment operator is designed to fill up the empty time slot due to the mold constraint. The proposed approach can also be easily extended to solve the same problem but with the fitness function of the total complete time. Experiments with and without the adjustment operator are made to analyze the performance of the proposed approach. Experimental results show that the adjustment operator does increase the performance of the scheduling.

Keywords: Identical Machine, Evolutionary Computation, Scheduling, Makespan, Adjustment Operator

Issue 8, Volume 4, August 2009

Title of the Paper:  Theoretical and Practical Aspects of Heating Equation


Authors: Marius-Constantin Popescu, Valentina E. Balas, Gheorghe Manolea, Liliana Perescu-Popescu, Nikos Mastorakis

Abstract: We are interested in a null controllability problem for a class of strongly degenerate heat equations. Heat equation parameters are represented graphically (temperature, heat flux) for a particular situation. Then, first for all T>0, we prove a regional null controllability result at time T at least in the region where the equation is not degenerate. The proof is based on an adequate observability inequality for the homogeneous adjoint problem. This inequality is obtained by application of Carleman estimates combined with the introduction of cut-off functions. Then we improve this result: for all T`>T, we obtain a result of persistent regional null controllability during the time interval [T,T]. We give similar results for the (non degenerate) heat equation in unbounded domain. Analysis by numerical simulation of the heating room space has highlighted that the use of composite materials instead of the usual materials of construction is more advantageous in terms of achieving the microclimate conditions, making possible, within certain limits of temperature exterior, a passive air conditioning, which involves reducing energy consumption.

Keywords: Representation equations, Control, Null controllability, Air conditioning

Title of the Paper:  Theory and Application of the Composed Fuzzy Measure of L-Measure and Delta-Measures


Authors: Hsiang-Chuan Liu, Chin-Chun Chen, Der-Bang Wu, Tian-Wei Sheu

Abstract: The well known fuzzy measures, λ-measure and P-measure, have only one formulaic solution. Two multivalent fuzzy measures with infinitely many solutions were proposed by our previous works, called L-measure and δ-measure, but the former do not include the additive measure as the latter and the latter has not so many measure solutions as the former. Due to the above drawbacks, in this paper, an improved fuzzy measure composed of above both, denoted Lδ -measure, is proposed. For evaluating the Choquet integral regression models with our proposed fuzzy measure and other different ones, a real data experiment by using a 5-fold cross-validation mean square error (MSE) is conducted. The performances of Choquet integral regression models with fuzzy measure based Lδ -measure, L-measure, δ-measure, λ-measure, and P-measure, respectively, a ridge regression model, and a multiple linear regression model are compared. Experimental result shows that the Choquet integral regression models with respect to extensional L-measure based on γ-support outperforms others forecasting models.

Keywords: Lambda-measure, P-measure, Delta-measure, Gamma-support, composed fuzzy measure, Choquet integral regression model

Title of the Paper:  Actual Situation and Perspectives on Wind Energy Usage in Banat Region


Authors: I. Szeidert, O. Prostean, N. Budisan, I. Filip, V. E. Balas, G. Prostean

Abstract: This paper presents synthetically some of the actual trends in the unconventional energy resources in case of non-polluting wind energy. There are presented the worldwide efforts engaged on the increase of the wind energy usage and particularly in the Banat Region, Romania. There is presented the experience of the researchers from Banat Area and their most important achievements. There is highlighted the importance of the induction generator in the wind energy conversion systems and there are stated conclusions based on practical implementations regarding the optimization of the operation of induction generators through terminal voltage control. There are identified the potential participants and the existing legal regulations regarding the wind energy utilization program and the potential investors. There are stated objective conclusions regarding the problematic of the wind energy usage in Romania.

Keywords: Wind energy usage, wind energy conversion systems (WECS), induction generator, synchronous generator, wind aggregates, legal regulations, wind programs

Title of the Paper:  Intelligent Steganalytic System: Application on Natural Language Environment


Authors: Roshidi Din, Azman Samsudin

Abstract: This paper presents a consolidated view of the computational intelligence used in the natural language steganalysis. In order to understand the human intelligence on natural language, four major computational intelligence methods have been identified. They are bayesian, fuzzy logic, neural network, and genetic algorithm. This paper also presents a measurement tool to measure the natural language intelligent system properties based on steganalysis objectives. It can be learned that the more suitable intelligent systems to be applied in steganalysis domain properties are: neural network, genetic algorithm and fuzzy logic.

Keywords: Computational Intelligence, Steganalysis, Intelligent Steganalytic System, Natural Language Steganalysis

Title of the Paper:  Modeling, Analysis and Motion Control of a Pan Tilt Platform based on Linear and Nonlinear Systems


Authors: Imran S. Sarwar, Javaid Iqbal, Afzaal M. Malik

Abstract: This paper deals with the modeling, analysis and controlled motion control of a two degree of freedom pan tilt platform (PTP) for positioning or aiming a device. The PTP has two revolute joints. The PTP is a device that makes it possible for the camera to point in a desired direction when mounted under a carrier such as an aircraft. The objective of this research work is to derive a linear and nonlinear control system of the PTP to point in a desired direction within allowable specifications. To perform the analysis and simulation, all the parameters involved in the system dynamics were identified. To achieve the motion control a feedback control system with PD controllers was simulated and tested for the position control of pan and tilt mechanism. These PD controllers were derived from linear system model were used in nonlinear control system simulation and tested with real system. The nonlinear control system developed in this paper is nearest to the physical system. The motion controller results matched closely with the simulation results.

Keywords: Linear model, Nonlinear model, Analysis, Motion control, Security system

Title of the Paper:  Controlled Jump Markov Processes with Local Transitions and their Fluid Approximation


Authors: Alexey Piunovskiy

Abstract: Stochastic jump processes, especially birth-and-death processes, are widely used in the queuing theory, computer networks and information transmission. The state of such process describes the instant length of the queues (numbers of packets at different edges to be transmitted through the net). If the birth and death rates are big, trajectories of such processes are close to the trajectories of deterministic dynamic systems. Therefore, if we consider the related optimal control problems, we expect that the optimal control strategy in the deterministic (‘fluid’) model will be nearly optimal in the underlying stochastic model. In the current paper, a new technique for calculating the accuracy of this approximation is described. In a nutshell, instead of the study of trajectories, we investigate the corresponding dynamic programming equations. It should be emphasized that we deal also with multiple-dimensional lattices, so that the results are applicable to complex communicating systems of queues. Other areas of application are population dynamics, mathematical epidemiology, and inventory systems.

Keywords: Birth-and-death process, Continuous time Markov chain, Fluid model, Optimal control, Queuing system, Dynamic programming, μC-rule, Inventory

Title of the Paper:  A Method and an Algorithm for Obtaining the Stable Oscillatory Regimes Parameters of the Nonlinear Systems, with Two Time Constants and Relay with Delay and Hysteresis


Authors: Nutu Vasile, Moldoveanu Cristian-Emil, Somoiag Pamfil

Abstract: The object of this paper is the oscillatory stable regime of a particular nonlinear system. This particular nonlinear system includes a relay, and its linear part is characterized by a transfer function with two time constants. In the beginning, the paper shows a method that can be used in the calculus of the parameters for the limit stable cycle, which is appropriated for these nonlinear systems. After that, the method is particularized for two different commutation lows of the relay nonlinearity: relay with hysteresis and relay with delay time. The different commutation laws induced, for the same linear parts, different shapes and parameters for the oscillatory stable regimes proper to assembly nonlinear system. These differences are presented in a case study.

Keywords: Nonlinear systems, oscillatory regime, relay, delay time, hysteresis, calculus method, algorithm

Issue 9, Volume 4, September 2009

Title of the Paper:  Lattices for 3-Dimensional Fuzzy Data Generated by Fuzzy Galois Connections


Authors: Narcis Clara

Abstract: Vagueness and high dimensional space data are usual features of current data. The paper is an approach to identify conceptual structures among fuzzy three dimensional data sets in order to get conceptual hierarchy. We propose a fuzzy extension of the Galois connections that allows to demonstrate an isomorphism theorem between fuzzy sets closures which is the basis for generating lattices ordered-sets.

Keywords: Fuzzy Ternary Relations, Fuzzy Galois Connections, Fuzzy Closure Operators, Isomorphism Theorem, Lattice

Title of the Paper:  Intelligent Supervision of Petroleum Processes based on Multi-Agent Systems


Authors: Miguel Angel Ramirez Canelon, Jacinto Davila, Eliezer Colina Morles

Abstract: This work presents a methodology for the design of an intelligent supervisory system that combines the principles of fuzzy logic, the Internal Model Control (IMC) architecture and the paradigm of Multi-Agent Systems (MAS). The methodology has been conceived to be applied in an intelligent supervisory system, specifically for two kinds of complex petroleum industrial processes: the gas-oil separation process and the oilheating process. The supervision proposal takes into account the fact of using standard local supervisors schemes connected between themselves and to a global supervisor so that local objectives in each process can be met, thereby letting the global or social objective be obtained through the application of basic mechanism of communication, cooperation and coordination; where these objectives have been previously defined and structured in a hierarchical manner. The paper includes some computational simulations performed under MATLAB / SIMULINK and the results obtained show a good overall system performance.

Keywords: Multi-Agent System, event detectors, intelligent supervisor system, internal model control

Title of the Paper:  A Neo-Fuzzy Approach for Bottom Parameters Estimation in Oil Wells


Authors: Edgar Camargo, Jose Aguilar, Addison Rios, Francklin Rivas, Joseph Aguilar-Martin

Abstract: In this work, an approach for the bottom parameters estimation in oil wells is presented. It is based on neural networks and fuzzy logic, specifically on the neo-fuzzy-neuron model. We propose a neo-fuzzy system compose by two neo-fuzzy neurons. For validating the results, the estimation is applied in oil wells based on the artificial gas lift method, using variables of the head of the wells, particularly the gas and production pressures.

Keywords: Neuro-fuzzy models, oil system production, artificial gas lift wells, parameters estimation, neo-fuzzy neurons, oil wells

Title of the Paper:  Methods for Parameters Identification of a HVAC Installation


Authors: Virginia Finca, Radu Zglimbea, Emilian Greaban, Constantin Marin

Abstract: This paper presents a procedure for time variant system identification based on some experimental studies. Some of the system parameters change in time according to unknown laws. These laws are expressed as finite degree time polynomials whose parameters are included in the set of parameters to be identified. Mainly it is an extension of the procedure developed in [1]. The theoretical methods are now applied on some concrete platform. Our paper presents the concretization of some experimental identification methods on experimental workbench from Quanser. HVAC installation is a test installation for controlling temperature in a chamber, and for parameters identification

Keywords: Continuous time systems, Identification, Nonlinear systems, HVAC, Quanser

Title of the Paper:  Stabilization of Linear Time-varying Uncertain Delay Systems with Double Triangular Configuration


Authors: Tomoaki Hashimoto, Takashi Amemiya

Abstract: This paper investigates the feedback stabilization problem of linear time-varying uncertain delay systems using linear memoryless state feedback control. Each uncertain parameter and each delay under consideration may take arbitrarily large values. In such a situation, the locations of uncertain entries in the system matrices play an important role. It has been shown that if a system has a particular configuration called a triangular configuration, then the system is stabilizable irrespectively of the given bounds of uncertain variations. In this paper, so far obtained stabilizability conditions are developed into the ones called a double triangular configuration. The objective of this paper is to show that if a system has such an extended configuration, then the system is also stabilizable independently of both the bounds of uncertain parameters and time delays. An illustrative example is presented to verify the effectiveness of the obtained result.

Keywords: Stabilization, Linear systems, Time delay, Uncertain systems, N-matrix

Title of the Paper:  Design of Control Systems Based on Vector Error


Authors: Oleg N. Agamalov

Abstract: A new approach to the design of control systems is offered. This approach based on definition the vector error allowing combining in real time a stage of identification of unknown plant and calculation of control. The measurement method of a vector error with use of Hilbert transform also it is shown.

Keywords: Vector error, identification, nonlinear system, Hilbert transform, stability

Issue 10, Volume 4, October 2009

Title of the Paper:  An Alternative Collection of Structural Invariants for Matrix Pencils under Strict Equivalence


Authors: A. Diaz, M. I. Garcia-Planas

Abstract: We consider pairs of matrices (E;A), representing singular linear time invariant systems in the form Ex_ (t) = Ax with E;A 2 Mp£n(C) under restricted equivalence. In this paper we obtain an alternative collection of invariants that they permit us to deduce the Kronecker canonical reduced form. As application we obtain a reduced form form systems under proportional and derivative feedback as well proportional and derivative output injection.

Keywords: Singular linear systems, canonical reduced form, structural invariants

Title of the Paper:  Some Observations on Development and Testing of a Simple Autotuning Algorithm for PID Controllers


Authors: Bohumil Sulc, Stanislav Vrana

Abstract: Although a wide range of control algorithms are available, PID controllers are still the most widely used type. Even control engineers who have a good knowledge of advanced control algorithms prefer PID controllers when they are asked to design the control circuit for a new device. This is because of their price and because of the simplicity and reliability of the control algorithm. The PID control algorithm enables anyone with a basic knowledge of mathematics to gain some idea of what happens inside the controller during the control process, how the manipulated value is computed and its dependence on the control error. The main disadvantage of standard PID type controllers is the absence of autotuning features. Implementation of such controllers requires time-consuming tuning, and very often the presence of expensive experts. Therefore, there is quite strong pressure to equip new PID controllers with simple autotuners. Recently, tuners based on relay experiments have become popular. However, the use of autotuners of this kind requires the control process to be stopped temporarily during the relay experiment. For these reasons, even controllers equipped with these autotuning facilities are used without any tuning, sometimes even with the factory presetting. This unsatisfactory situation has motivated us to develop a new frequency response based autotuning algorithm that does not use any model of the controlled plant and enables the controller parameters to be changed without the necessity to break the control process.

Keywords: PID controller, laboratory model, tuning, model-free, implementation, optimality, mathematical model, autotuning

Title of the Paper:  Vertical Transport Installations Balance Survey


Authors: Florin Dumitru Popescu, Ilie Mitran

Abstract: The operation of vertical transport installations are based on cable systems with electrical adjustable operation, which ensures the technical conditions regarding time variation in speed, the current in the main actuation engines and the acceleration during start-up and breaking. The actuation electrical systems are part of the category of the fast process of the automation equipment. For the vertical transport installation the size which has to be controlled from a command is the speed, the dependent factor being the tahogram. Adjusting determines the dependence of the sizes in the process, through a default law, both in relation to the independent sizes and in relation to the dependent ones from the process, assuring the reduction of the influence of harmful sizes to the process. The stability of an automatic system can be defined in different ways. We will consider stability of an automatic system, that feature which is that when it is subjected to the action of one harmful size of the moment the system will return in the end at the stationary phase. Thus, the Balance Survey also deals with the determination of variation functions in time of the current of the main actuation motor, of speed (main electrical actuation motor rpm) when starting the vertical transport installation, as well as the study in time of the variation of speed when applying loading shock.

Keywords: Nyquist stability criterion, place of transfer, transfer function, speed adjustment

Title of the Paper:  Simulation of the Heat Exchangers Dynamics in MATLAB & Simulink


Authors: Pavel Nevriva, Stepan Ozana, Ladislav Vilimec

Abstract: Heat exchangers that transfer energy from flue gas to steam are important units of thermal power stations. Their inertias are often decisive for the design of the steam temperature control system. In this paper, the analysis and the simulation of the dynamics of the steam superheater are discussed. Superheater is simulated as a unit of a control loop that generates steam of desired state values. To simulate the steam superheater on the computer, the exchanger is described by the set of partial differential equations. The equations are then solved numerically by modified finite difference method. Discussion of method and qualitative and quantitative results are presented. Paper describes use of Simulink S-functions which make it possible to set-up the most complex systems with complicated dynamics. There’s a comparison of M and C S-functions, which are two main approaches when building user-defined blocks in Simulink, regarding both the performance and the efficiency of the simulation for M and C versions of the codes and the possibility to perform a real-time simulation.

Keywords: Simulation, Heat exchangers, Superheaters, Partial differential equations, Finite difference method, MATLAB&Simulink, S-functions, Real-time

Issue 11, Volume 4, November 2009

Title of the Paper:  DSP based Simulator for Excitation Control of Synchronous Generator


Authors: Damir Sumina, Igor Erceg, Gorislav Erceg

Abstract: This paper proposes a DSP based simulator for the implementing and testing control algorithms. The simulator is used to control a synchronous power plant model in real time. The simulator consists of a PC, on which the synchronous generator connected to AC network is simulated, connected through a communication channel to a DSP into which the control algorithm has been implemented. The simulator enables verification of the control algorithm on a simulation model in real time. In real time the simulator enables faster processes of engineering, implementing and verifying control algorithms not only for the voltage control system of a synchronous generator, but also for other systems able of having mathematical and simulation models. This paper shows a comparison in the case when both the system model and the control structure are simulated and for a case when the model is simulated on a computer and the control structure implemented in the DSP. The implementation of a conventional and a nonlinear synchronous generator voltage control structure has been presented. These methods were tested in the cases of voltage reference change, mechanical power change and the case of a short circuit on the transmission line.

Keywords: Real time simulation, DSP based simulator, synchronous generator, excitation control, nonlinear control

Title of the Paper:  A Theoretical and Empirical Analysis of Convergence Related Particle Swarm Optimization


Authors: Milan R. Rapaic, Zeljko Kanovic, Zoran D. Jelicic

Abstract: In this paper an extensive theoretical and empirical analysis of recently introduced Particle Swarm Optimization algorithm with Convergence Related parameters (CR-PSO) is presented. The convergence of the classical PSO algorithm is addressed in detail. The conditions that should be imposed on parameters of the algorithm in order for it to converge in mean-square have been derived. The practical implications of these conditions have been discussed. Based on these implications a novel, recently proposed parameterization scheme for the PSO has been introduced. The novel optimizer is tested on an extended set of benchmarks and the results are compared to the PSO with time-varying acceleration coefficients (TVAC-PSO) and the standard genetic algorithm (GA).

Keywords: Global Optimization, Swarm Intelligence, Evolutionary Computation, Particle Swarm Optimization (PSO), Algorithm Analysis

Title of the Paper:  Analysis of Quality Parameters Influence to Translation of IPTV Service


Authors: Rasa Bruzgiene, Lina Narbutaite, Tomas Adomkus

Abstract: The most important for everyone of people to have good time and relax during TV translations in the work day evening. Nowadays interactive TV, as IPTV (Internet Protocol Television - digital television, transmiting over IP networks) is very popular in each country. TV signals for end-users are transmitted by broadcast Internet network, using Internet protocol (IP). The most important for end-user is receiving qualitative IPTV service with no any interference during TV translation. One of the most impact for qualitative IPTV service is effective and optimal assignment of data streams. It depends on processing time of data streams in nodes of network. Operative assignment of data streams is a critical problem for qualitative broadcasting of IPTV service. In this paper we analyse the assignment of data streams in core and access networks, influence of intensity and delay for assignment of data streams in different nodes of real and simulated IPTV networks. The main results showed that the efficiency of real IPTV network is less than efficiency of simulated IPTV network.

Keywords: IPTV, MOS, Data streams, Video streams, Delay, IPTV Headend, Access network, End – user, Quality of IPTV, STB

Title of the Paper:  New Management for the Control Three Tank System


Authors: Marius-Constantin Popescu, Gheorghe Manolea, Liliana Perescu-Popescu, Nikos Mastorakis

Abstract: The development of fuzzy regulators designed for conduction of neminimum faze sistems need a great volum of work conected to: defining the basic rules, chosing the values of free parameters of fuzzy regulators and checking the stability of the automated guiding sistems with fuzzy regulators. The objectives of this paper consists in the application of FuzzyLib library regulators to develop quasi-fuzzy PI Mamdani-type equipment for laboratory management system with three tanks and the modification of software and interface to enhance the existing flexibility in the sense of providing the facility to develop more regulators.

Keywords: Nonlinear mathematical model, Fuzzy regulators

Issue 12, Volume 4, December 2009

Title of the Paper:  Componentwise Stability of the Singular Discrete Time System using the Methodology of the Drazin Inverse


Authors: Habiba Mejhed, Nour El Houda Mejhed, Abdlaziz Hmamed

Abstract: The asymptotic (exponential) stability in the sense of componentwise approach is considered for one and two dimensional linear discrete-time singular systems. The two dimensional system is described by Fornasini-Marchesini model. The main motivation for these results is the need, particularly felt in the evaluation in a more detailed manner of the dynamical behaviour of linear discrete-time singular systems. Combining the basic theory of Drazin inverse and the results reported in the case of the discrete time linear systems (see Hmamed, 1997), both necessary and sufficient conditions are established ensuring the componentwise asymptotic (exponential) stability. In addition, numerical examples are proposed to illustrate the correctness of the obtained results.

Keywords: Componentwise stability; Singular system; discrete time systems; 2D Fornasini-Marchesini model; Drazin inverse theory

Title of the Paper:  Dynamic Behavior of Closed Grinding Systems and Effective PID Parameterization


Authors: Dimitris Tsamatsoulis

Abstract: The object of the present study is to investigate the dynamic of closed circuit cement mills and based on that to tune robust PID controllers applied to three actual installations. The model that has been developed, consisting of integral part, time delay and a first order filter, is based exclusively on industrial data sets collected in a period more than one year. The model parameters uncertainty is also assessed varying from 28% to 36% as the gain is concerning and 34% to 42% as regards the time delay. As significant sources of model uncertainty are determined the grinding of various cement types in the same cement mill and the decrease of the ball charge during the time. The Internal Model Control (IMC) and M - Constrained Integral Gain Optimization (MIGO) methods are utilized to adjust the controller parameters. Specially by implementing the MIGO technique robust controllers are built deriving a daily average IAE 2.3-3% of the set point value. Due to the high flexibility and effectiveness of MIGO, the controllers can be parameterized by taking into account the cement type ground and the power absorbed. Subsequently the attenuation of main uncertainties leads to improvement of the regulation performance.

Keywords: Dynamic, Cement, Mill, Grinding, Model, Uncertainty, PID, tuning, robustness, sensitivity

Title of the Paper:  An Adaptive Quantum-based Evolutionary Algorithm for Multiobjective Optimization


Authors: Jerzy Balicki

Abstract: An Adaptive Quantum-based Multi-criterion Evolutionary Algorithm called AQMEA is a new paradigm of decision making for complex systems. Quantum-based algorithms utilize a new representation for the smallest unit of information, called a Q-bit, for the probabilistic representation that is based on the concept of qubits. Evolutionary computing with Q-bit chromosomes has a better characteristic of population diversity than other representations, since it can represent linear superposition of states probabilistically. Moreover, we consider the three-criterion problem of task assignment.

Keywords: Quantum algorithms, multi-criterion optimization, distributed systems

Title of the Paper:  Robust Motion Control of Biped Walking Robots


Authors: Ashraf A. Zaher, Mohammed A. Zohdy

Abstract: This paper proposes a robust mathematical approach for motion control. The proposed control tech-nique is applied to a three-degree of freedom Biped walking robot for illustration. The design technique is di-vided into two major steps; the first one is to establish a robust position control scheme with both guaranteed stability and trajectory tracking capability using a model-reference technique that assumes only the knowledge of the upper bound of the model uncertainty. The performance of this step is investigated for the two cases of point-to-point and trajectory-following motions. The second step is to design an intelligent path planner for the walking Biped that takes all motion constraints into account. Animation is used to check for both motion har-mony and trajectory following. The real-time applicability of the proposed controller is investigated and tra-deoffs between stability and performance are carefully studied. In addition, real-time potential of the controller is being studied for further application.

Keywords: Model-Reference Control, Robotics, GAIT Analysis, and Modeling and Simulation

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