Electrical - Electronic Engineering / Elektrik - Elektronik Mühendisliği
Permanent URI for this collectionhttps://hdl.handle.net/11147/11
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Article Model-free output feedback controller design for twin rotor systems(Muğla Sıtkı Koçman Üniversitesi, 2020) Deniz, Meryem; Tatlıcıoğlu, 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.Conference Object A New Continuous Velocity Observer Formulation for a Class of Uncertain Nonlinear Mechanical Systems(Institute of Electrical and Electronics Engineers, 2015) Bayrak, Alper; Tatlıcıoğlu, Enver; Zergeroǧlu, 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.Conference Object Citation - WoS: 4Citation - Scopus: 5Backstepping Control of Electro-Hydraulic Arm(Institute of Electrical and Electronics Engineers, 2018) Bayrak, Alper; Tatlıcıoğlu, Enver; Zergeroǧlu, 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.Article Citation - WoS: 1Experimental Verification of Lead-Lag Compensators on a Twin Rotor System(De Gruyter, 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.Article Citation - WoS: 4Citation - Scopus: 3A Model-Free Continuous Velocity Observer Formulation With Self-Tuning for Mechatronic Systems(The American Society of Mechanical Engineers(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.Conference Object Citation - WoS: 5Citation - Scopus: 7Online Time Delay Estimation in Networked Control Systems With Application To Bilateral Teleoperation(Institute of Electrical and Electronics Engineers Inc., 2017) 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.Article Citation - WoS: 5Citation - Scopus: 5Robust Output Tracking Control of an Unmanned Aerial Vehicle Subject To Additive State Dependent Disturbance(Institution of Engineering and Technology, 2016) Tanyer, İlker; Tatlıcıoglu, Enver; Zergeroglu, Erkan; Deniz, Meryem; Bayrak, Alper; Özdemirel, BarbarosIn 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.Article Citation - WoS: 4Citation - Scopus: 5An Asymptotically Stable Robust Controller Formulation for a Class of Mimo Nonlinear Systems With Uncertain Dynamics(Taylor and 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.Article Citation - WoS: 11Citation - Scopus: 11Design of an Experimental Twin-Rotor Multi-Input Multi-Output System(John Wiley and Sons Inc., 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. © 2015 Wiley Periodicals, Inc.Conference Object Citation - WoS: 28Citation - Scopus: 34A New Robust 'integral of Sign of Error' Feedback Controller With Adaptive Compensation Gain(Institute of Electrical and Electronics Engineers Inc., 2013) Bıdıklı, Barış; Tatlıcıoğlu, Enver; Bayrak, Alper; Zergeroğlu, ErkanIn this paper, a new robust integral of signum of error (RISE) feedback type controller is designed for a class of uncertain nonlinear systems. Unlike the previous versions of RISE feedback type controllers, the proposed controller does not require prior knowledge of upper bounds of the vector containing the uncertainties of the dynamical system plus desired system dynamics (and their derivatives) for the control gain selection. The aforementioned enhancement is made possible via the design of a time-varying compensation gain as opposed to a constant gain used in previous RISE feedback type controllers. Asymptotic stability of the error signals and the boundedness of the closed-loop system signals are ensured via Lyapunov based arguments. Numerical simulation studies are presented to illustrate the viability of the proposed method. ©2013 IEEE.