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2011

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Articles 721 - 750 of 789

Full-Text Articles in Computer Engineering

Ecg Denoising On Bivariate Shrinkage Function Exploiting Interscale Dependency Of Wavelet Coefficients, Sema Kayhan, Ergun Erçelebi̇ Jan 2011

Ecg Denoising On Bivariate Shrinkage Function Exploiting Interscale Dependency Of Wavelet Coefficients, Sema Kayhan, Ergun Erçelebi̇

Turkish Journal of Electrical Engineering and Computer Sciences

This paper presents a new method for electrocardiogram (ECG) denoising based on bivariate shrinkage functions exploiting the interscale dependency of wavelet coefficients. Most nonlinear thresholding methods based on wavelet transform denoising assume that the wavelet coefficients are independent. However, wavelet coefficients of ECG signals have significant dependencies. In this paper, we proposed a new method by considering the dependencies between the coefficients and their parents in detail on a bivariate shrinkage function for denoising of an ECG signal corrupted by different types of noises, such as muscle artifact noise, electrode motion, and white noise. In real-time applications, reduction of computational …

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A Complete Motor Protection Algorithm Based On Pca And Ann: A Real Time Study, Okan Özgönenel, Turgay Yalçin Jan 2011

A Complete Motor Protection Algorithm Based On Pca And Ann: A Real Time Study, Okan Özgönenel, Turgay Yalçin

Turkish Journal of Electrical Engineering and Computer Sciences

Protection of an induction motor (IM) against possible faults, such as a stator winding fault, due to thermal deterioration, rotor bar and bearing failures, is very important in environments in which it is used intensively, as in industry as an actuator. In this work, a real time digital protection algorithm based on principal component analysis (PCA) and neural network method is presented for induction motors. The proposed protection algorithm covers internal winding faults (also known as stator faults), broken rotor bar faults, and bearing faults. Many laboratory experiments have been performed on a specially designed induction motor to evaluate the …

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A Study On Influence Of Borax To Polyester Insulators, Aysel Ersoy, Ayten Kuntman Jan 2011

A Study On Influence Of Borax To Polyester Insulators, Aysel Ersoy, Ayten Kuntman

Turkish Journal of Electrical Engineering and Computer Sciences

In this study the effect of borax on polyester insulators is investigated by evaluating the tracking and erosion resistance using the inclined plane test. The test procedure follows the ASTM D2303 standard. During the test, 50 Hz current was acquired from the ground electrode allowing a sampling rate of 48000 samples per second. The effect of borax concentration on the glass transition and the degradation temperature is studied by employing differential scanning calorimetry (DSC) analysis. The addition of borax to the unsaturated polyester resulted in an increase in the glass transition temperature, while the addition of 0.5% of borax by …

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On The Existence Of Common Lyapunov Functions For Consensus Algorithms Based On Averaging, Mehmet Akar, Robert Shorten Jan 2011

On The Existence Of Common Lyapunov Functions For Consensus Algorithms Based On Averaging, Mehmet Akar, Robert Shorten

Turkish Journal of Electrical Engineering and Computer Sciences

This paper addresses distributed deterministic consensus algorithms based on averaging. We relate the conditions for achieving consensus to the existence of a common norm for a set of row-stochastic matrices associated with the original set of averaging matrices. For a system to achieve consensus, it is shown that this associated set of matrices should have a Common Lyapunov Function, even if the original set might not have one.

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Decentralized Robust Load-Frequency Control Of Power System Based On Quantitative Feedback Theory, Aidin Sakhavati, Gevork Gharehpetian, Seyed Hossein Hosseini Jan 2011

Decentralized Robust Load-Frequency Control Of Power System Based On Quantitative Feedback Theory, Aidin Sakhavati, Gevork Gharehpetian, Seyed Hossein Hosseini

Turkish Journal of Electrical Engineering and Computer Sciences

This paper aims at investigating the problem of Load Frequency Control (LFC) in interconnected power systems in order to obtain robustness against uncertainties. A design method for a robust controller, based on Quantitative Feedback Theory (QFT), has been presented in this paper. For a two-area power system, the simulation results show that the system response with the proposed QFT controller exhibits transient response beyond PI controllers. It is also shown that the transient response of the tie line power can also be improved.

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Sliding Mode Controller Gain Adaptation And Chattering Reduction Techniques For Dsp-Based Pm Dc Motor Drives, Mehmet Dal, Remus Teodorescu Jan 2011

Sliding Mode Controller Gain Adaptation And Chattering Reduction Techniques For Dsp-Based Pm Dc Motor Drives, Mehmet Dal, Remus Teodorescu

Turkish Journal of Electrical Engineering and Computer Sciences

In order to achieve and maintain the prospective benefits of sliding mode control (SMC) methodology, the phenomenon known as ``chattering'', the main obstacle encountered in real-time applications, has to be suppressed. In this study, two promising switching control gain adaptation and chattering reduction techniques are investigated, and the effectiveness of chattering suppression for current regulation of PM DC drives is tested. The sampling rate was also examined to determine how it affects the amplitude of chattering. This paper concentrates on various combinations of observer-based methods in order to find the best solution for chattering reduction. To find a practical solution …

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Minimization Of Load Shedding By Sequential Use Of Linear Programming And Particle Swarm Optimization, Mehrdad Tarafdar Hagh, Sadjad Galvani Jan 2011

Minimization Of Load Shedding By Sequential Use Of Linear Programming And Particle Swarm Optimization, Mehrdad Tarafdar Hagh, Sadjad Galvani

Turkish Journal of Electrical Engineering and Computer Sciences

Minimization of load shedding during contingency conditions is solved as an optimization problem. As a new topic, instead of local load shedding, total load shedding of a large power system is considered. Power generation rescheduling is considered to minimize the load shedding, as well. Different importance factors for buses are also considered. The linear programming method (LP) is used to solve this problem in a short period of time without considering some power system constraints. Particle swarm optimization (PSO) is also used to solve the problem by considering all power system constraints, but with a longer solving time. Finally, a …

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Design Of Cdba-Based Active Polyphase Filter For Low-If Receiver Applications, Mehmet Sağbaş Jan 2011

Design Of Cdba-Based Active Polyphase Filter For Low-If Receiver Applications, Mehmet Sağbaş

Turkish Journal of Electrical Engineering and Computer Sciences

A novel first-order active-RC polyphase filter section, using current differencing buffered amplifiers (CDBAs), is presented. The section uses 6 resistors, 2 capacitors, and 2 CDBAs. The transfer function of the proposed section has a single pole and optionally a single zero. Increasing the number of cascading sections, any higher order polyphase filter can be realized. This paper also introduces the leakage caused by element deviation and the effects of the amplifier in nonideal cases. Furthermore, nonideal performances of the proposed filter section are tested with PSpice simulations.

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A Unified Series-Parallel Active Filter System For Nonperiodic Disturbances, Mehmet Uçar, Şule Özdemi̇r, Engi̇n Özdemi̇r Jan 2011

A Unified Series-Parallel Active Filter System For Nonperiodic Disturbances, Mehmet Uçar, Şule Özdemi̇r, Engi̇n Özdemi̇r

Turkish Journal of Electrical Engineering and Computer Sciences

This paper presents a 3-phase, 4-wire unified series-parallel active filter (USPAF) system for periodic and nonperiodic disturbance compensation using a generalized nonactive power theory. The USPAF system consists of a series active filter (AF), parallel AF, and split DC-link capacitors with the midpoint of the DC-link connected to the neutral wire. The generalized nonactive power theory is applicable to single-phase or multiphase, sinusoidal or nonsinusoidal, periodic or nonperiodic, and balanced or unbalanced electrical systems. The theory was implemented previously in a parallel AF. In this study, the USPAF system is proposed to compensate for the nonsinusoidal and nonperiodic currents and …

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A Novel Expression For Resonant Length Obtained By Using Artificial Bee Colony Algorithm In Calculating Resonant Frequency Of C-Shaped Compact Microstrip Antennas, Ali̇ Akdağli, Mustafa Berkan Bi̇çer, Seda Ermi̇ş Jan 2011

A Novel Expression For Resonant Length Obtained By Using Artificial Bee Colony Algorithm In Calculating Resonant Frequency Of C-Shaped Compact Microstrip Antennas, Ali̇ Akdağli, Mustafa Berkan Bi̇çer, Seda Ermi̇ş

Turkish Journal of Electrical Engineering and Computer Sciences

This paper presents a novel and simple expression for resonant length to calculate the resonant frequency of C-shaped compact microstrip antennas operating on UHF band applications. C-shaped compact microstrip antennas with different physical dimensions and electrical parameters were simulated by means of a software package that employs the method of finite difference time domain. With the aid of the artificial bee colony algorithm, an expression for the resonant length depending on physical dimensions was constructed by using simulation data. The resonant length expression provided less than 1.6% error on average over the simulated 144 antennas. A comparison between the results …

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Applying The Finite Element Method To Analyze Predischarge Lightning Rods, Chin-Tsung Hsieh, Meng-Hui Wang, Cho-Yu Pan Jan 2011

Applying The Finite Element Method To Analyze Predischarge Lightning Rods, Chin-Tsung Hsieh, Meng-Hui Wang, Cho-Yu Pan

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, the finite element method is applied for analyzing 4 types of lightning rods in order to select the optimal lightning rod configuration. First, software is used to calculate the 2D protective coverage of different lighting rods, and 4 kinds of typical lightning rods are simulated in different conditions. The analyzed results are then applied for the selection of the optimal lighting rod and the frame of the lighting rod. The analyzed results would be useful for electrical engineers to design lightning rods that offer the most effective lighting protection; the simulated results are also useful for the …

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A New, Improved Cmos Realization Of Cdta And Its Filter Applications, Firat Kaçar, Hulusi̇ Hakan Kuntman Jan 2011

A New, Improved Cmos Realization Of Cdta And Its Filter Applications, Firat Kaçar, Hulusi̇ Hakan Kuntman

Turkish Journal of Electrical Engineering and Computer Sciences

This paper presents a high-performance current differencing transconductance amplifier (CDTA), a recently reported active element, especially suitable for analog signal processing applications. A high linearity CMOS configuration for a CDTA is made up of high linearity input and output stages. The proposed CDTA provides high output impedance at port X and excellent input/output current tracking. A biquad filter circuit was chosen as an application example in order to demonstrate the performance of the CDTA. PSpice simulation results using a TSMC 0.35-\mu m CMOS process model were included to verify the expected values.

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Measuring Traffic Flow And Classifying Vehicle Types: A Surveillance Video Based Approach, Erhan İnce Jan 2011

Measuring Traffic Flow And Classifying Vehicle Types: A Surveillance Video Based Approach, Erhan İnce

Turkish Journal of Electrical Engineering and Computer Sciences

The paper presents a vehicle counting method based on invariant moments and shadow aware foreground masks. Estimation of the background and the segmentation of foreground regions can be done using either the Mixture of Gaussians model (MoG) or an improved version of the Group Based Histogram (GBH) technique. The work demonstrates that, even though the improved GBH method delivers performance just as good as MoG, considering computational efficiency, MoG is more suitable. Shadow aware binary masks for each frame are formed by using background subtraction and shadow removal in the Hue Saturation and Value (HSV) domain. To determine new vehicles …

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A Fuzzy Rule-Based System For Predicting The Live Weight Of Holstein Cows Whose Body Dimensions Were Determined By Image Analysis, Şaki̇r Taşdemi̇r, Abdullah Ürkmez, Şeref İnal Jan 2011

A Fuzzy Rule-Based System For Predicting The Live Weight Of Holstein Cows Whose Body Dimensions Were Determined By Image Analysis, Şaki̇r Taşdemi̇r, Abdullah Ürkmez, Şeref İnal

Turkish Journal of Electrical Engineering and Computer Sciences

The aim of this study was to determine the body measurement of Holstein cows through image analysis (IA) and to estimate their live weight (LW) by means of a fuzzy rule-based model using the body measurements. For this purpose, a photography environment was established at a dairy cattle farm where a large number of cows were kept. First, digital photographs of each animal were synchronously taken from different directions with Canon EOS 400D cameras. At the same time, body dimensions, namely wither height (WH), hip height (HH), body length (BL), and hip width (HW), of the cows were manually measured …

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Fully Parallel Ann-Based Arrhythmia Classifier On A Single-Chip Fpga: Fpaac, Ahmet Turan Özdemi̇r, Kenan Danişman Jan 2011

Fully Parallel Ann-Based Arrhythmia Classifier On A Single-Chip Fpga: Fpaac, Ahmet Turan Özdemi̇r, Kenan Danişman

Turkish Journal of Electrical Engineering and Computer Sciences

Recognition of cardiac arrhythmias by electrocardiogram (ECG) is an important issue for diagnosis of cardiac abnormalities. Many studies on recognition of cardiac arrhythmias by ECG, using various techniques, have been performed in the past 20 years. Artificial neural networks (ANNs) are the most widely used tool in medical diagnosis systems (MDS) because of their powerful prediction characteristics. An ANN model is inspired by real biological neural networks, with a parallel structure that is potentially fast for computation. However, the suggested ANN architectures in the literature can only be run sequentially, on powerful processors, due to their complexity. Our approach enables …

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Learning Control Of Robot Manipulators In The Presence Of Additive Disturbances, Enver Tatlicioğlu Jan 2011

Learning Control Of Robot Manipulators In The Presence Of Additive Disturbances, Enver Tatlicioğlu

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, a learning controller for robot manipulators is developed. The controller is proven to yield in a semi-global asymptotic result in the presence of additive input and output disturbances. Lyapunov-based techniques are used to guarantee that the tracking error is asymptotically driven to zero. Numerical simulation results are presented to demonstrate the viability of the proposed learning controller.

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A Multi-Lateral Rehabilitation System, Aykut Ci̇han Satici, Ahmetcan Erdoğan, Volkan Patoğlu Jan 2011

A Multi-Lateral Rehabilitation System, Aykut Ci̇han Satici, Ahmetcan Erdoğan, Volkan Patoğlu

Turkish Journal of Electrical Engineering and Computer Sciences

This paper proposes a multi-lateral shared control concept for robot assisted rehabilitation. In particular, a dual-user force-feedback teleoperation control architecture is implemented on a forearm-wrist rehabilitation system consisting of two kinematically dissimilar robotic devices. The multi-lateral rehabilitation system allows for patients to train with on-line virtual dynamic tasks in collaboration with a therapist. Different control authority can be assigned to each agent so that therapists can guide or evaluate movements of patients, or share the control with them. The collaboration is implemented using a dual-user force-feedback teleoperation control architecture, in which a dominance factor determines the authority of each agent …

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Design And Control Of The Humanoid Robot Suralp, Kemaletti̇n Erbatur, Utku Seven, Evri̇m Taşkiran, Özer Koca, Meti̇n Yilmaz, Mustafa Ünel, Güllü Kiziltaş Şendur, Asif Sabanovic, Ahmet Onat Jan 2011

Design And Control Of The Humanoid Robot Suralp, Kemaletti̇n Erbatur, Utku Seven, Evri̇m Taşkiran, Özer Koca, Meti̇n Yilmaz, Mustafa Ünel, Güllü Kiziltaş Şendur, Asif Sabanovic, Ahmet Onat

Turkish Journal of Electrical Engineering and Computer Sciences

SURALP is a 29 degrees-of-freedom full-body walking humanoid robot designed and constructed at Sabanci University - Turkey. The human-sized robot is actuated by DC motors, belt and pulley systems and Harmonic Drive reduction gears. The sensory equipment consists of joint encoders, force/torque sensors, inertial measurement systems and cameras. The control hardware is based on a dSpace digital signal processor. This paper reviews the design of this robot and presents experimental walking results. A posture zeroing procedure is followed after manual zeroing of the robot joints. Controllers for landing impact reduction, early landing trajectory modification, foot-ground orientation compliance, body inclination and …

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Ellipsoid Based L_2 Controller Design For Lpv Systems With Saturating Actuators, İbrahi̇m Beklan Küçükdemi̇ral, Levent Ucun, Yavuz Eren, Haluk Görgün, Gali̇p Cansever Jan 2011

Ellipsoid Based L_2 Controller Design For Lpv Systems With Saturating Actuators, İbrahi̇m Beklan Küçükdemi̇ral, Levent Ucun, Yavuz Eren, Haluk Görgün, Gali̇p Cansever

Turkish Journal of Electrical Engineering and Computer Sciences

This paper addresses the L_2 gain control problem for disturbance attenuation in Linear Parameter Varying (LPV) Systems having saturating actuators when the system is subjected to L_2 disturbances. In the presented method, saturating actuator is expressed analytically with a convex hull of some linear feedback which let us construct L_2 control problem via Linear Matrix Inequalities (LMIs) which are obtained by some ellipsoids. It is shown that the stability and disturbance rejection capabilities of the control system are all measured by means of these nested ellipsoids where the inner ellipsoid covers the initial conditions for states whereas the outer ellipsoid …

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Spoiler Effects Reduction With Using Active Power Filter On A Direct Torque Controlled Induction Machine, İbrahi̇m Alişkan, Kayhan Gülez, Yusuf Altun Jan 2011

Spoiler Effects Reduction With Using Active Power Filter On A Direct Torque Controlled Induction Machine, İbrahi̇m Alişkan, Kayhan Gülez, Yusuf Altun

Turkish Journal of Electrical Engineering and Computer Sciences

Harmonics, which may be placed in electrical systems, have important effects on performance parameters of electrical motors. In this paper, effects of electrical power system voltage harmonics on torque position of induction motors are dealt with. System modeling with Pulse Width Modulation (PWM) type Active Power Filter (APF) is used for reducing these effects. APF, as a subsystem, is placed into torque control system entrance to save the control system and induction motor output torque. Motor outputs, that are before-after APF connections, are handed for understanding effects of voltage harmonics. Since APF design was based on voltage harmonics, Electromagnetic Interference …

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Semi-Active H_{\Infty} Robust Control Of Six Degree Of Freedom Structural System Using Mr Damper, Şaban Çeti̇n, Seli̇m Si̇vri̇oğlu, Erkan Zergeroğlu, İsmai̇l Yüksek Jan 2011

Semi-Active H_{\Infty} Robust Control Of Six Degree Of Freedom Structural System Using Mr Damper, Şaban Çeti̇n, Seli̇m Si̇vri̇oğlu, Erkan Zergeroğlu, İsmai̇l Yüksek

Turkish Journal of Electrical Engineering and Computer Sciences

In this study, H_{\infty} robust control is designed for vibration attenuation of six DOF structure using MR damper. A semi-active seismically excited, nonlinear structural system is modelled. The controller is designed for a reduced order model and applied to the full order model. The controller performance is verified experimentally. It is shown that the H_{\infty} controller performance is satisfactory to suppress the vibration of the structure despite the presence of uncertainties.

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Vibrations Control Of Light Rail Transportation Vehicle Via Pid Type Fuzzy Controller Using Parameters Adaptive Method, Muzaffer Meti̇n, Rahmi̇ Güçlü Jan 2011

Vibrations Control Of Light Rail Transportation Vehicle Via Pid Type Fuzzy Controller Using Parameters Adaptive Method, Muzaffer Meti̇n, Rahmi̇ Güçlü

Turkish Journal of Electrical Engineering and Computer Sciences

In this study, a conventional PID type fuzzy controller and parameter adaptive fuzzy controller are designed to control vibrations actively of a light rail transport vehicle which modeled as 6 degree-of-freedom system and compared performances of these two controllers. Rail vehicle model consists of a passenger seat and its suspension system, vehicle body, bogie, primary and secondary suspensions and wheels. The similarity between mathematical model and real system is shown by comparing uncontrolled simulation results and vibration measurements. For carrying a comfortable travel, rail vehicle body and passenger seat vibrations are minimized by adding a controller between rail vehicle body …

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Model Predictive Controller Design Of Hydrocracker Reactors, Di̇la Gökçe Jan 2011

Model Predictive Controller Design Of Hydrocracker Reactors, Di̇la Gökçe

Turkish Journal of Electrical Engineering and Computer Sciences

This study summarizes the design of a Model Predictive Controller (MPC) in Tüpraş, İzmit Refinery Hydrocracker Unit Reactors. Hydrocracking process, in which heavy vacuum gasoil is converted into lighter and valuable products at high temperature and pressure is described briefly. Controller design description, identification and modeling studies are examined and the model variables are presented. WABT (Weighted Average Bed Temperature) equalization and conversion increase are simulated, results are discussed.

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Design And Development Of A Tilt-Wing Uav, Ertuğrul Çeti̇nsoy, Efe Sirimoğlu, Kaan Taha Öner, Cevdet Hançer, Mustafa Ünel, Mahmut Faruk Akşi̇t, İlyas Kandemi̇r, Kayhan Gülez Jan 2011

Design And Development Of A Tilt-Wing Uav, Ertuğrul Çeti̇nsoy, Efe Sirimoğlu, Kaan Taha Öner, Cevdet Hançer, Mustafa Ünel, Mahmut Faruk Akşi̇t, İlyas Kandemi̇r, Kayhan Gülez

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, the mechanical and aerodynamic design, carbon composite production, hierarchical control system design and vertical flight tests of a new unmanned aerial vehicle (UAV), which is capable of VTOL (vertical takeoff and landing) like a helicopter and long range horizontal flight like an airplane, are presented. Real flight tests show that the aerial vehicle can successfully operate in VTOL mode. Kalman filtering is employed to obtain accurate roll and pitch angle estimations.

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Linear Motor For Multi--Car Elevators: Design And Position Measurement, Çağri Gürbüz, Ender Kazan, Ahmet Onat, Sandor Markon Jan 2011

Linear Motor For Multi--Car Elevators: Design And Position Measurement, Çağri Gürbüz, Ender Kazan, Ahmet Onat, Sandor Markon

Turkish Journal of Electrical Engineering and Computer Sciences

Multi-car elevator is an emerging technology consisting of two or more elevator cars moving independently in an elevator hoistway, which has become more appealing as building heights increase. In this paper, the design and drive methodologies for a linear motor driven multi-car elevator system with independently moving cars is introduced together with experimental results. Additionally, a safety method developed for the linear motor elevator and the conditions necessary for its proper operation are discussed. The new results introduced in this paper are in the areas of the design method of the linear motor for multi-car elevator system, and the preliminary …

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Active Vibration Control Of Seismic Excited Structural System Using Lmi-Based Mixed H_2/H_{\Infty} State Feedback Controller, Hakan Yazici, Rahmi̇ Güçlü Jan 2011

Active Vibration Control Of Seismic Excited Structural System Using Lmi-Based Mixed H_2/H_{\Infty} State Feedback Controller, Hakan Yazici, Rahmi̇ Güçlü

Turkish Journal of Electrical Engineering and Computer Sciences

This paper is concerned with the active vibration control of a four-degree-of-freedom structure, which is effected by earthquake. To obtain desired time history and frequency responses for solution of active vibration control problem, Linear Matrix Inequality (LMI) based state-feedback mixed H_2/H_{\infty} controller is designed in this study. The time history of ground motion of the Kobe earthquake in 1995, which is a disturbance input, is applied to modeled structure. At the end of the study, the time history of the storey displacements, velocities and frequency responses of both controlled and uncontrolled cases are presented and results are discussed. Performance of …

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Delay Compensation In Bilateral Control Using A Sliding Mode Observer, Tuğba Leblebi̇ci̇, Berk Çalli, Mustafa Ünel, Asif Sabanovic, Seta Bogosyan, Meti̇n Gökaşan Jan 2011

Delay Compensation In Bilateral Control Using A Sliding Mode Observer, Tuğba Leblebi̇ci̇, Berk Çalli, Mustafa Ünel, Asif Sabanovic, Seta Bogosyan, Meti̇n Gökaşan

Turkish Journal of Electrical Engineering and Computer Sciences

In bilateral control applications, time delays in the communication channel have destabilizing effects and cause degradations in the performance of the system. In this paper, a sliding mode observer is used in conjunction with a disturbance observer to predict states of the slave system. Predicted states are then used in control formulation. Simulation and experimental results show that the proposed method avoids instability due to time delays in bilateral operation and provides satisfactory performance.

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Induction Motor, State Estimation, Extended Kalman Filtering, Recurrent Neural Networks, Saadetti̇n Aksoy, Aydin Mühürcü Jan 2011

Induction Motor, State Estimation, Extended Kalman Filtering, Recurrent Neural Networks, Saadetti̇n Aksoy, Aydin Mühürcü

Turkish Journal of Electrical Engineering and Computer Sciences

This study presents a recurrent neural network (RNN)-based nonlinear state estimator that uses an Elman neural network structure (ENN) for state estimation of a squirrel-cage induction motor. The proposed algorithm only uses the measurements of the stator currents and the rotor angular speed, and it learns the dynamic behavior of the state observer from these measurements through prediction error minimization. A squirrel-cage induction motor was fed from sinusoidal, 6-step, and pulse-width modulation (PWM) supply sources at different times in order to observe the performance of the proposed estimator for different operation conditions. Estimation results showed that the proposed algorithm is …

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Application Of A Hybrid Evolutionary Technique For Efficiency Determination Of A Submersible Induction Motor, Mümtaz Mutluer, Osman Bi̇lgi̇n Jan 2011

Application Of A Hybrid Evolutionary Technique For Efficiency Determination Of A Submersible Induction Motor, Mümtaz Mutluer, Osman Bi̇lgi̇n

Turkish Journal of Electrical Engineering and Computer Sciences

Electric motors are the largest consumers of electricity in plants and induction motors constitute nearly two-thirds of them. The replacement of in-service induction motors with more efficient ones is a very important strategy for energy savings and consequently nearly 30 different methods have been used to determine the efficiency of induction motors in the last 2 decades. This paper aims to develop the efficiency determination of a 20 Hp submersible induction motor. Due to getting perfect efficiency of the submersible induction motor, a robust hybrid evolutionary optimization technique, which consists of a genetic algorithm and simulated annealing, is used. The …

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A Stationary, Variable Dof Flight Control System For An Unmanned Quadrocopter, Vasfi̇ Emre Ömürlü, Ahmet Kirli, Utku Büyükşahi̇n, Şeref Naci̇ Engi̇n, Sedat Kurtoğlu Jan 2011

A Stationary, Variable Dof Flight Control System For An Unmanned Quadrocopter, Vasfi̇ Emre Ömürlü, Ahmet Kirli, Utku Büyükşahi̇n, Şeref Naci̇ Engi̇n, Sedat Kurtoğlu

Turkish Journal of Electrical Engineering and Computer Sciences

Unmanned air vehicles (UAV) and especially quadrocopters have drawn great attention in recent years because of their maneuverability and nonlinear control problem. Most of the related research concentrate on control; yet, design and communication are also some sub-topics. In this paper, a stationary, four rotor air vehicle with limited/controlled degree of freedom is constructed so that various control algorithms and their changing effects with varying vehicle dynamics can be studied on the ground for safety purposes. Ascending/descending, pitch/yaw/roll motions can be limited by setting the vehicle's degree of freedom mechanically, resulting better net observability of the control algorithms on the …

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