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Öğe An asymptotically stable robust controller formulation for a class of MIMO nonlinear systems with uncertain dynamics(Taylor & Francis Ltd, 2016) Bıdıklı, Barış; Tatlıcıoğlu, Enver; Zergeroğlu, Erkan; Bayrak, AlperIn this work, we present a novel continuous robust controller for a class of multi-input/multi-output nonlinear systems that contains unstructured uncertainties in their drift vectors and input matrices. The proposed controller compensates uncertainties in the system dynamics and achieves asymptotic tracking while requiring only the knowledge of the sign of the leading principal minors of the input gain matrix. A Lyapunov-based argument backed up with an integral inequality is applied to prove the asymptotic stability of the closed-loop system. Simulation results are presented to illustrate the viability of the proposed method.Öğe Automatic synchronization unit for the parallel operation of synchronous generators(Ieee, 2009) Bekiroğlu, Erdal; Bayrak, AlperIn this study, an automatic synchronization unit has been developed for the parallel connection of synchronous generators. Two synchronous generators are connected in parallel automatically with the developed control unit. Synchronous generators are also connected in parallel with the line. The voltages, frequencies, phase sequences and synchronism time data have been transferred to the microcontroller. These data are monitored and evaluated by the control algorithm coded into the microcontroller. Parallel operation of generators are realized automatically when all parallel connection conditions are occur. The system doesn't require additional measuring tools for monitoring and control processes. The developed automatic synchronization unit is fast, cost effective, reliable and precise to be used for monitoring, measurement and parallel operation of the synchronous generators.Öğe Backstepping control of electro-hydraulic arm(Ieee, 2018) Bayrak, Alper; Tatlıcıoğlu, Enver; Zergeroğlu, ErkanIn this study, positioning control of the electro hydraulic systems is considered. Backstepping control strategy is designed by defining an auxiliary error signal. The performance of the controller is investigated by conducting numerical simulations. From the simulation results, it is seen that the control objective achieved successfully. The performance is compared with PI controller via a comparison criteria and it is seen that the backstepping controller has better results in both error and controller performance aspects.Öğe Design of an experimental twin-rotor multi-input multi-output system(Wiley, 2015) Bayrak, Alper; Doğan, Fırat; Tatlıcıoğlu, Enver; Özdemirel, BarbarosTwin-rotor multi-input multi-output system (TRMS) is a popular experimental setup utilized mostly for development and evaluation of aerovehicle control algorithms. Motivated by its popularity, construction steps of a TRMS setup in an academic setting are presented in this paper. Specifically, design of mechanical and electronic hardware components and development of related computer software are described in detail. Preliminary experiment results are also presented to demonstrate the performance of the system. (c) 2015 Wiley Periodicals, Inc. Comput Appl Eng Educ 23:578-586, 2015; View this article online at ; DOIÖğe Design of an experimental wind tunnel system for control applications(Sage Publications Ltd, 2019) Bayrak, AlperIn this study, a low-cost experimental wind tunnel system for evaluation of control algorithms and utilization in teaching activities is presented. The system is designed inspired from conventional wind tunnels and has a basic design and low cost as can be realized in every laboratory. The design of mechanical part and electronics hardware and development of computer software are described in detail. The objective of the control system is to ensure the rotation speed of fan, which is placed at the end of the pipe, and track a desired trajectory by controlling air pressure in the pipe. Experimental results are also presented to demonstrate the performance of the system.Öğe Experimental verification of lead-lag compensators on a twin rotor system(De Gruyter Poland Sp Zoo, 2018) Deniz, Meryem; Tatlıcıoğlu, Enver; Bayrak, AlperTwin rotor system is a laboratory setup resembling a simplified helicopter model that moves along both horizontal and vertical axes. The literature on control of twin rotor systems reflects a good amount of research on designing PM controllers and their extensions considering several aspects, as well as onsome nonlinear controllers. However, there is almost no previous work on design of lag-lead type compensators for twin rotor systems. In this study, by considering this open research problem, lag and lead type compensators are designed and then experimentally verified on the twin rotor system. Specifically, first, lag and lag-lag compensators are designed to obtain a reduced steady state error as compared with proportional controllers. Secondly, lead compensation is discussed to obtain a reduced overshoot. Finally, lag-lead compensators are designed to make use of their favorable properties. All compensators are applied to the twin rotor system in our laboratory. From experimental studies, it was observed that steady state error was reduced when a lag compensator was used in conjunction with a lead compensator.Öğe Lyapunov Based Observer Design for Electro-Hydraulic Arm System(2022) Önder, Mithat; Bayrak, Alper; Aksoy, SerkanIn this paper, a Lyapunov based observer design is proposed to observe the load pressure of electro-hydraulic arm systems. The stability of the observer is investigated by using the Lyapunov based method. In the stability analysis, it is proven that the observer error converge to the vicinity of origin which can be adjusted to be arbitrarily small. The classical PID controller is used to control the position of the electro-hydraulic arm system and keep the system states bounded. The performance of the designed observer is evaluated by computational simulations which are conducted in MATLAB Simulink program. The performance of the observer is tested in two cases: i) noise free case and ii) noise case. In the noisy case, the state ??2 is exposed to the 30 dB additive white Gaussian noise. The computational simulation results are given to demonstrate that the proposed observer work efficiently in both noise free and noisy cases.Öğe A Model-Free Continuous Velocity Observer Formulation With Self-Tuning for Mechatronic Systems(Asme, 2018) Deniz, Meryem; Bayrak, Alper; Tatlıcıoğlu, Enver; Zergeroğlu, ErkanIn this study, the design of a smooth robust velocity observer for a class of uncertain nonlinear mechatronic systems is presented. The proposed velocity observer does not require a priori knowledge of the upper bounds of the uncertain system dynamics and introduces time-varying observer gains for uncertainty compensation. Practical stability of the velocity observation error is ensured via Lyapunov-type stability analysis. Experimental results obtained from Phantom Omni haptic device are presented to illustrate the performance of the proposed velocity observer.Öğe MODEL-FREE OUTPUT FEEDBACK CONTROLLER DESIGN FOR TWIN ROTOR SYSTEMS(2020) Deniz, Meryem; Tatlicioğlu, Enver; Bayrak, AlperIn this work, tracking control of twin rotor systems is aimed. The control problem is restricted by the lack ofmathematical model of the twin rotor and further complicated by the unavailability of the angular velocitymeasurements. A model–free controller in conjunction with a high gain observer is designed. Experiments performed on atwin rotor system demonstrates the viability of the controller–observer couple.Öğe Modelling twin rotor system with artificial neural networks(Ieee, 2015) Deniz, Meryem; Bıdıklı, Barış; Bayrak, Alper; Özdemirel, Barbaros; Tatlıcıoğlu, EnverIn this study, the input output relation of the twin rotor system which was constructed in our laboratory is obtained by using ANNs. When compared with the existing literature, main advantage of this modelling approach is that multi input multi output ANN structure is used preferred. As a result of this approach, the cross coupling effects, between the rotors and also between the outputs, are taken into consideration. Thus, we sincerely believe that the obtained input output model demonstrates a close behavior to the real system.Öğe A new continuous velocity observer formulation for a class of uncertain nonlinear mechanical systems(Ieee, 2015) Bayrak, Alper; Tatlıcıoğlu, Enver; Zergeroğlu, Erkan; Deniz, MeryemIn this study, we present a smooth robust velocity observer for a class of uncertain nonlinear mechanical systems. The smoothness of the observers is guaranteed by utilizing hyperbolic tangent function as opposed to signum-type functions applied in most robust and sliding mode observers found in the literature. The proposed observer does not require a priori knowledge of an upper bound of the uncertain system dynamics and introduces a time-varying observer gain for uncertainty compensation. Practical stability of the observer error is ensured via Lyapunov-type stability analysis. Numerical simulation studies backed up by experimental results are presented to illustrate the performance of the proposed observer.Öğe A novel adaptable isometric strength analysis and exercise development system design(Sage Publications Ltd, 2021) Fidan, Murat; Bayrak, Alper; Karlı, ÜmidIn this study, a low-cost and adaptable isometric strength measurement and exercise development system are described. The implemented system consists of mechanical structure, force measurement sensor, electronic circuit, and computer software. Isometric-isotonic (via spring resistance) strength analysis and various exercise programs can be applied with the system. The developed system has a lower cost compared to its counterparts in the literature and has a structure that can be adapted to different machines and measuring methods. The operability and reliability of the isometric strength measurement and exercise development system have been proven by calibration tests.Öğe A novel adaptive time delay identification technique(Elsevier Science Inc, 2023) Bayrak, Alper; Tatlıcıoğlu, EnverIn this work, a novel online adaptive time delay identification method is proposed for a class of signal processing and communication applications, where the received signal is a combination of the transmitted signal and its delayed forms with the delay values being uncertain and required to be estimated. The design relies on a filtered form of a prediction error-like term which is then used in the design of the novel nonlinear adaptive update law. The stability of the identification algorithm is then investigated via novel Lyapunov based tools and the time delay identification is proven to be globally uniformly ultimately bounded. Several numerical simulations are conducted to evaluate the performance of the proposed identifier where constant, slowly varying and suddenly changing delays are successfully identified even in the presence of additive noise.& COPY; 2023 Published by Elsevier Ltd on behalf of ISA.Öğe On-line educational tool for the parallel operation of the synchronous generators(Wiley, 2011) Bekiroğlu, Erdal; Bayrak, AlperThis study presents a PC and a PIC microcontroller based an on-line educational tool for the monitoring and controlling of the parallel operation of the synchronous generators. The presented tool measures the voltages, the frequencies, the phase sequences, and the synchronism time data of the generators through microcontroller. The measured data, the voltage graphics, and the status of the parallel operation conditions are monitored on the computer instantaneously. The parallel operation of the generators is controlled with the developed tool automatically. The educational tool is user-friendly, real-time, reliable, and precise. (C) 2009 Wiley Periodicals, Inc. Comput Appl Eng Educ 19: 669-677, 2011; View this article online at wileyonlinelibrary.com/journal/cae; DOI 10.1002/cae.20351Öğe Online time delay estimation in networked control systems with application to bilateral teleoperation(Ieee, 2016) Çetin, Kamil; Bayrak, Alper; Tatlıcıoğlu, EnverThe problem of forward and backward time delays is significantly important for both control and feedback loop of networked control systems. These time delays give rise to latency in performance and thereby may destabilize the system. Therefore numerous methods have been proposed about time delay identification/estimation and compensation for networked control systems, especially for bilateral teleoperation systems. However, most compensation methods have been accomplished by considering offline time delay estimation for linear/nonlinear time delay control systems. In this work, we propose an observer based estimation algorithm for round trip delay which is the sum of forward and backward time delays for a 1 degree-of-freedom nonlinear bilateral teleoperation system. Via Lyapunov based stability analysis, global boundedness of the observer errors along with their ultimate convergence and the convergence of the round trip delay estimator to the vicinity of its real value can be guaranteed in the closed loop system. Finally, simulation and experimental studies are carried out utilizing the last link of a PHANToM Omni Haptic device moving like a one link robot in the vertical plane.Öğe RISE-based backstepping control design for an electro-hydraulic arm system withparametric uncertainties(TAYLOR & FRANCIS LTD, 2022) Önder, Mithat; Bayrak, Alper; Aksoy, SerkanIn this paper, a self-tuning Robust Integral of Sign of Error (RISE)-based backstepping controller is designed for an electro-hydraulic arm system with a fourth-order system model. The RISE controller, which constitutes the robust part of the control rule, is fused with a backstepping control strategy to cope with model-based and parametric uncertainties. Different from a classical RISE control rule, a tanh(center dot) function is used instead of a sgn(center dot) function to obtain a more smooth control signal. All the gains in the RISE controller are tuned by using continuous update rules. The efficiency of the controller is demonstrated by conducting numerical simulations.Öğe Robust output tracking control of an unmanned aerial vehicle subject to additive state dependent disturbance(Inst Engineering Technology-Iet, 2016) Tanyer, İlker; Tatlıcıoğlu, Enver; Zergeroğlu, Erkan; Deniz, Meryem; Bayrak, AlperIn this study, an asymptotic tracking controller is developed for an aircraft model subject to additive, state-dependent, non-linear disturbance-like terms. Dynamic inversion technique in conjunction with robust integral of the sign of the error term is utilised in the controller design. Compared to the previous studies, the need of acceleration measurements of the aircraft have been removed. In addition, the proposed controller design utilises only the output of aircraft dynamics. Lyapunov based analysis is applied to prove global asymptotic convergence of the tracking error signal. Numerical simulation results are presented to illustrate the performance of the proposed robust controller.Öğe Sanal elektrik makinaları laboratuarı: Senkron jeneratör deneyleri(2010) Bekiroğlu, Erdal; Bayrak, AlperBu çalışmada, senkron jeneratör deneylerinin bilgisayar ortamında yapılabilmesini sağlayan sanal bir elektrik makinaları laboratuar aracı geliştirilmiştir. Geliştirilen araç ile senkron jeneratörlere ait boş çalışma, kısa devre, yüklü çalışma ve paralel bağlama deneyleri yapılmaktadır. Her deney için ayrı bir deney sayfası açılarak, deneyin yapılışı, bağlantı şeması, tablo ve grafikler gösterilmektedir. C#.NET platformu kullanılarak geliştirilen sanal laboratuar aracı kullanıcı dostu olarak tasarlanmıştır. Benzetim çalışmaları için jeneratörün modeli ve pratik deneylerden yararlanılmıştır. Geliştirilen sanal laboratuar aracı, konu ile ilgili eğitim alan öğrencilerin senkron jeneratörleri daha iyi kavramasına yardımcı olacak, gerekli laboratuar donanımlarının kurulmadığı birimlerde öğrencilere bilgisayar ortamında deneyleri yapma olanağı sağlayacaktır.Öğe A self-tuning robust full-state feedback control design for the magnetic levitation system(Pergamon-Elsevier Science Ltd, 2018) Bıdıklı, Barış; Bayrak, AlperIn this study, a self-tuning robust integral of signum of error (RISE) based controller is designed and used to control a magnetic levitation (maglev) system. In the control design, unlike the classical RISE controller, 'truth' function is used instead of 'signum' function to obtain a more smooth control signal. The gains of the controller are updated according to a time-varying update rule. Convergence of the error under the closed-loop operation is proven via Lyapurtov-based stability analysis. The controller is tested on an experimental maglev system and successful results are obtained.Öğe Sliding mode based Self-Tuning PID controller for second order systems(2017) Bayrak, AlperIn this paper, a sliding mode based self-tuning PID controller is proposed for uncertain second order systems. While developing the controller, it is assumed that the system model has a part which contains nonlinear terms similar to PID structure which is a new approach in the literature. The controller and update rules for controller parameters are obtained from Lyapunov stability analysis. The proposed controller with update rule is experienced on an experimental 2-DOF helicopter which is also known as Twin-Rotor Multi-Input Multi-Output System (TRMS). From experiments, it was seen that the PID parameter update rules run satisfactorily and, in parallel with this, the controller achieved the control objective by providing the system track the desired trajectory.
