Electrical - Electronic Engineering / Elektrik - Elektronik Mühendisliği

Permanent URI for this collectionhttps://hdl.handle.net/11147/11

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Now showing 1 - 10 of 34
  • Article
    Model-free output feedback controller design for twin rotor systems
    (Muğla Sıtkı Koçman Üniversitesi, 2020) Deniz, Meryem; Tatlıcıoğlu, Enver; Bayrak, Alper
    In 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
    Citation - Scopus: 5
    Adaptive Visual Servo Regulation Control for Camera-In Configuration With a Fixed Camera Extension
    (Institute of Electrical and Electronics Engineers Inc., 2007) Tatlıcıoğlu, Enver; Dawson, Darren M.; Xian, B.
    In this paper, image-based regulation control of a robot manipulator with an uncalibrated vision system is discussed. To compensate for the unknown camera calibration parameters, a novel prediction error formulation is presented. To achieve the control objectives, a Lyapunov-based adaptive control strategy is employed. The control development for the camera-in-hand problem is presented in detail and a fixed-camera problem is included as an extension.
  • Conference Object
    İha'lar için Gürbüz Takip Denetçisi
    (Institute of Electrical and Electronics Engineers Inc., 2013) Tanyer, İlker; Tatlıcıoğlu, Enver; Zergeroǧlu, Erkan
    In this study, a nonlinear control technique that guarantee exponential output tracking for unmanned aerial vehicles subject to uncertainties in system dynamics and additive nonlinear disturbances is developed. In the literature, dynamic inversion method which is a nonlinear control technique commonly used within the aerospace community to replace aircraft dynamics with a reference model. Dynamic inversion and robust control methods were usually utilized together to compensate for the uncertainties and ensure output tracking. Review of the literature highlights the fact that, in previous works, estimate of the uncertain system matrices was used in the controller design. In our study, we removed the requirement for the estimate of the uncertain system matrices and yet still guarantee exponential tracking of a reference model.
  • 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, Meryem
    In 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: 4
    Citation - Scopus: 5
    Backstepping Control of Electro-Hydraulic Arm
    (Institute of Electrical and Electronics Engineers, 2018) Bayrak, Alper; Tatlıcıoğlu, Enver; Zergeroǧlu, Erkan
    In 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: 1
    Experimental Verification of Lead-Lag Compensators on a Twin Rotor System
    (De Gruyter, 2018) Deniz, Meryem; Tatlıcıoğlu, Enver; Bayrak, Alper
    Twin 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.
  • Conference Object
    Citation - WoS: 1
    Citation - Scopus: 1
    A Dynamic Model Free Observer Based Output Feedback Tracking Control of Robot Manipulators in Task-Space
    (Institute of Electrical and Electronics Engineers Inc., 2018) Çobanoğlu, Necati; Çetin, Kamil; Tatlıcıoğlu, Enver; Zergeroğlu, Erkan
    This paper addresses the output feedback end-effector position tracking control of robotic manipulators. Specifically, via the design of a novel dynamic model independent observer constructed through a Lyapunov type analysis and under the assumption that the manipulator Jacobian is always invertible, we propose a model based nonlinear controller which ensures asymptotic robot end-effector tracking without the need of joint and/or task space velocity measurements. Simulation results are included to illustrate the performance and effectiveness of the proposed method.
  • Conference Object
    Cerrahın Anlık Yönlendirilebildiği Robot Yardımlı Endoskop Kontrol Sistemi Mimarisi - Neuroboscope
    (Boğaziçi Üniversitesi, 2018) Dede, Mehmet İsmet Can; Kiper, Gökhan; Ayav, Tolga; Tatlıcıoğlu, Enver; Özdemirel, Barbaros; Maaroof, Omar; Ateş, Gizem; Berker, Mustafa; Işıkay, İlkay; Hanalioğlu, Şahin
    Bu bildiride ele alınan çalışmada endoskopik hipofiz cerrahisinde kullanılan optik-kamera sistemini, cerrahın anlık isteklerini takip ederek yönlendirilmesine izin verecek robotik sistem geliştirilmektedir. Cerrah kendisi ameliyat sahasında ameliyatı gerçekleştirirken robotu yönlendirmesi gerekmektedir. Bu gereksinim için geliştirilmekte olan özgün alt bileşenler ve toplam sistem mimarisi bildiri içinde tanıtılmıştır ve çalışmanın sonuçları benzer minimal invaziv ameliyatların robot destekli ameliyata dönüşmesine imkan verebilecektir. Bildiride sistemin gereksinimlerinin oluşturulması için yapılan testler anlatılmıştır. Üzerinde durulan sistem gereksinimlerinden birisi robotun çalışma alanı, diğeri ise cerrahın kullanım kolaylığı ile ilgilidir.
  • Conference Object
    Citation - WoS: 2
    Citation - Scopus: 3
    On Null-Space Control of Kinematically Redundant Robot Manipulators
    (Institute of Electrical and Electronics Engineers Inc., 2016) Çetin, Kamil; Tatlıcıoğlu, Enver; Zergeroğlu, Erkan
    In this study, we consider the null-space control problem of redundant robot manipulators. Specifically for robot manipulators with kinematically redundancy where at least one extra degree of freedom is present, we introduce a sub-task controller that will ensure the use of the extra degrees of freedom for possible control purposes while still ensuring the main objective. The stability of the main (end-effector tracking) and sub-task objectives are obtained via Lyapunov based arguments. Extension to adaptive controller formulation for robotic devices with uncertain system dynamics is also presented. Numerical studies for the adaptive controller are presented to illustrate the liability of the proposed method.
  • Conference Object
    Citation - WoS: 5
    Citation - Scopus: 7
    Online 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, Enver
    The 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.