Electrical - Electronic Engineering / Elektrik - Elektronik Mühendisliği
Permanent URI for this collectionhttps://hdl.handle.net/11147/11
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Article Citation - WoS: 1Citation - Scopus: 1Experimental Demonstration of a Transient Grating Controlled All-Optical Switch(IOP Publishing, 2023) Akın, Osman; Dinleyici, Mehmet SalihWe demonstrate an on-fiber all-optical switching device based on a transient grating formed by the interference of control laser pulses in a Kerr-type nonlinear material placed in the evanescent region of the fiber. The device can operate in two distinctive modes. First, switching/coupling among the fiber modes using bulk index modulation was investigated and an efficiency of about %0.55 @852 nm was measured. Second, by exploiting Four Wave Mixing (FWM), an all-optical switching that transfers power among light signals with wavelengths of λ 1 = 440 nm and λ 2 = 663 nm was achieved by quasi-phase-matching and fRequency matching in a nonlinear thin polymeric film. The results prove that the introduced switching structure may have the potential to be used in integrated photonic applications such as intensity modulators or controllable couplers.Article Citation - WoS: 9Citation - Scopus: 13Effect of Faraday Mirror Imperfections in a Fiber Optic Current Sensor Dedicated To Iter(Elsevier Ltd., 2019) Karabulut, Doğuş; Miazin, Anton; Gusarov, Andrei; Moreau, Philippe; Leysen, Willem; Megret, Patrice; Wuilpart, MarcPlasma current measurements in ITER are safety-related and must therefore satisfy a very demanding specification. In this paper, the use of the Fiber Optics Current Sensor (FOCS) operating in the reflection mode with a Faraday mirror to perform plasma current measurements is analyzed. Based on the Jones matrix formalism, we performed numerical simulations to investigate the impact of the Faraday mirror detuning on the measurement accuracy. We show that the use of standard commercial components does not allow to satisfy the ITER requirements for the whole plasma current range. A simple solution to the problem is proposed, which consists in taking into account a mirror calibration in the current estimator. We show that the achievable mirror calibration accuracy is sufficient to fulfill the ITER requirements.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: 14Citation - Scopus: 16Charge Feedback-Based Robust Position Tracking Control for Piezoelectric Actuators(Institution of Engineering and Technology, 2012) Salah, M. H.; McIntyre, M. L.; Dawson, Darren M.; Wagner, John R.; Tatlıcıoğlu, Envern this study, the Coleman-hysteresis model is utilised in the piezoelectric actuator (PZTA) dynamic model and a non-linear robust control strategy is then developed to actively control the displacement of the PZTA effective tip. The proposed control technique is designed based on the partial knowledge of the hysteresis model while the mass of the PZTA is assumed to be uncertain. The piezoelectric charge measurement is utilised in the controller design to reduce the effects of the hysteresis. Lyapunov-based stability analysis techniques are utilised to ensure that a desired displacement trajectory is accurately tracked. Representative numerical results are presented and discussed to demonstrate the tracking performance of several desired displacement trajectories with different frequencies and amplitudes. Finally, comparisons with a standard PID controller and a sliding mode controller were performed to examine the effectiveness of the proposed control design. © 2012 The Institution of Engineering and Technology.Article Citation - WoS: 36Citation - Scopus: 38Optimum Seeking-Based Non-Linear Controller To Maximise Energy Capture in a Variable Speed Wind Turbine(Institution of Engineering and Technology, 2012) Iyasere, Erhun; Salah, Mohammed; Dawson, Darren M.; Wagner, John R.; Tatlıcıoğlu, EnverIn this study, an optimum seeking-based robust non-linear controller is proposed to maximise wind energy captured by variable speed wind turbines at low-to-medium wind speeds. The proposed strategy simultaneously controls the blade pitch angle and tip-speed ratio, through the turbine rotor angular speed, to an optimal point at which the power coefficient, and hence the wind turbine efficiency, is maximum. The optimal points are given to the controller by an optimisation algorithm that seeks the unknown optimal blade pitch angle and rotor speed. The control method allows for aerodynamic rotor power maximisation without exact knowledge of the wind turbine model. A representative numerical simulation is presented to show that the wind turbine can be accurately controlled to achieve maximum energy capture. © 2012 The Institution of Engineering and Technology.