Electrical - Electronic Engineering / Elektrik - Elektronik Mühendisliği
Permanent URI for this collectionhttps://hdl.handle.net/11147/11
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Article Citation - WoS: 16Citation - Scopus: 16Learning Control of Robot Manipulators in Task Space(John Wiley and Sons Inc., 2018) Doğan, Kadriye Merve; Tatlıcıoğlu, Enver; Zergeroğlu, Erkan; Çetin, KamilTwo important properties of industrial tasks performed by robot manipulators, namely, periodicity (i.e., repetitive nature) of the task and the need for the task to be performed by the end-effector, motivated this work. Not being able to utilize the robot manipulator dynamics due to uncertainties complicated the control design. In a seemingly novel departure from the existing works in the literature, the tracking problem is formulated in the task space and the control input torque is aimed to decrease the task space tracking error directly without making use of inverse kinematics at the position level. A repetitive learning controller is designed which “learns” the overall uncertainties in the robot manipulator dynamics. The stability of the closed-loop system and asymptotic end-effector tracking of a periodic desired trajectory are guaranteed via Lyapunov based analysis methods. Experiments performed on an in-house developed robot manipulator are presented to illustrate the performance and viability of the proposed controller.Conference Object Citation - WoS: 3Citation - Scopus: 4Neural Network Based Repetitive Learning Control of Robot Manipulators(Institute of Electrical and Electronics Engineers Inc., 2017) Çobanoğlu, Necati; Tatlıcıoğlu, Enver; Zergeroğlu, ErkanControl of robot manipulators performing periodic tasks is considered in this work. The control problem is complicated by presence of uncertainties in the robot manipulator's dynamic model. To address this restriction, a model free repetitive learning controller design is aimed. To reduce the heavy control effort, a neural network based compensation term is fused with the repetitive learning controller. The convergence of the tracking error to the origin is ensured via Lyapunov based techniques. Numerical simulations and experiments are performed to demonstrate the viability of the proposed controller.Conference Object Citation - WoS: 2Citation - Scopus: 3On Null-Space Control of Kinematically Redundant Robot Manipulators(Institute of Electrical and Electronics Engineers Inc., 2016) Çetin, Kamil; Tatlıcıoğlu, Enver; Zergeroğlu, ErkanIn 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.Article Citation - WoS: 14Citation - Scopus: 20Non-Linear Control of Variable-Speed Wind Turbines With Permanent Magnet Synchronous Generators: a Robust Backstepping Approach(Taylor and Francis Ltd., 2016) Şeker, Murat; Zergeroğlu, Erkan; Tatlıcıoğlu, EnverIn this study, a robust backstepping approach for the control problem of the variable-speed wind turbine with a permanent magnet synchronous generator is presented. Specifically, to overcome the negative effects of parametric uncertainties in both mechanical and electrical subsystems, a robust controller with a differentiable compensation term is proposed. The proposed methodology ensures the generator velocity tracking error to uniformly approach a small bound where practical tracking is achieved. Stability of the overall system is ensured by Lyapunov-based arguments. Comparative simulation studies with a standard proportional-integral-type controller are performed to illustrate the effectiveness, feasibility and efficiency of the proposed controller. © 2015 Taylor & Francis.Conference Object Citation - WoS: 2Citation - Scopus: 1A Self-Tuning Velocity Observer Formulation for a Class of Nonlinear Systems(Institute of Electrical and Electronics Engineers Inc., 2016) Bıdıklı, Barış; Tatlıcıoğlu, Enver; Zergeroğlu, ErkanThis work presents the design and the corresponding stability analysis of a model free velocity observer formulation for nonlinear systems modeled by Euler-Lagrange formulation. The observation gains of the proposed formulation are tuned online according to an update algorithm removing the burden of observation gain tuning. Lyapunov based arguments are applied to prove the overall system stability. Performance of the observer proposed is illustrated via extensive simulation studies. Experimental studies are also utilized to demonstrate the viability of the proposed formulation.Conference Object Citation - WoS: 3Citation - Scopus: 5Robust Control Design for Positioning of an Unactuated Surface Vessel(Institute of Electrical and Electronics Engineers Inc., 2015) Bıdıklı, Barış; Tatlıcıoğlu, Enver; Zergeroğlu, ErkanIn this paper, a robust controller is designed to achieve accurate positioning of an unactuated surface vessel by using multiple unidirectional tugboats. After initially locating opposing tugboats to specific configurations, the control problem is transformed into a second order system with an uncertain non-symmetric input gain matrix. Upon applying a matrix decomposition, a robust controller is proposed. Detailed stability analysis ensured asymptotic tracking. Numerical simulation results demonstrate the efficiency of the proposed controller © 2015 IEEE.Conference Object Citation - WoS: 6Citation - Scopus: 7Lyapunov-Based Output Feedback Learning Control of Robot Manipulators(Institute of Electrical and Electronics Engineers Inc., 2015) Doğan, Kadriye Merve; Tatlıcıoğlu, Enver; Zergeroğlu, Erkan; Çetin, KamilThis paper address the output feedback learning tracking control problem for robot manipulators with repetitive desired joint level trajectories. Specifically, an observer-based output feedback learning controller for periodic trajectories with known period have been proposed. The proposed learning controller guarantees semi-global asymptotic tracking despite the existence of parametric uncertainties associated with the robot dynamics and lack of velocity measurements. A learning-based feedforward term in conjunction with a novel observer formulation is designed to obtain the aforementioned result. The stability of the controller-observer couple is guaranteed via Lyapunov based arguments. Numerical studies performed on a two link robot manipulator are also presented to demonstrate the viability of the proposed method. © 2015 American Automatic Control Council.Conference Object Citation - Scopus: 3A Robust Adaptive Tracking Controller for an Aircraft With Uncertain Dynamical Terms(Elsevier Ltd., 2014) Tanyer, İlker; Tatlıcıoğlu, Enver; Zergeroğlu, ErkanThis work presents, the design and the corresponding analysis of a nonlinear controller for an aircraft system subject to uncertainties in the dynamics and additive state-dependent nonlinear disturbance-like terms. Specifically; dynamic inversion technique in conjunction with a robust integral of the signum of the error feedback and an adaptive term is utilized in the overall controller design. Lyapunov based stability analysis techniques are then utilized to prove global asymptotic convergence of the tracking error. © IFAC.Conference Object Citation - WoS: 23Citation - Scopus: 23A self tuning RISE controller formulation(Institute of Electrical and Electronics Engineers Inc., 2014) Bıdıklı, Barış; Tatlıcıoğlu, Enver; Zergeroğlu, ErkanIn recent years, controller formulations using robust integral of sign of error (RISE) type feedback have been successfully applied to a variety of nonlinear dynamical systems. The drawback of these type of controllers however, are (i) the need of prior knowledge of the upper bounds of the system uncertainties and (ii) the absence of a proper gain tuning methodology. To tackle the aforementioned weaknesses, in our previous work [1] we have presented a RISE formulation with a time-varying compensation gain to cope for the need of upper bound of the uncertain system. In this study, we have extended our previous design to obtain a fully self tuning RISE feedback formulation. Lyapunov based arguments are applied to prove overall system stability and extensive numerical simulation studies are presented to illustrate the performance of the proposed method. © 2014 American Automatic Control Council.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.