Yazar "Demiroglu, Ugur" seçeneğine göre listele

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    Fractional order proportional derivative control for first order plus time delay plants: achieving phase and gain specifications simultaneously
    (Sage Publications Ltd, 2019) Senol, Bilal; Demiroglu, Ugur
    The aim of the method in this paper is to achieve desired gain and phase specifications for robustness and performance of first order plus time delay plants. The previously proposed method frequency frame, implemented for tuning fractional order proportional integral controllers, is applied on such plants controlled with a fractional order proportional derivative controller. Four specifications of gain and phase are considered in the Bode plot inspired from an ideal system. The frame is drawn enclosing the magnitude and phase curves limited by gain and phase crossover frequencies. Then, the size of the frame is tuned to provide loop-shaping of the curves to meet desired properties. The iso-damping property is achieved by shaping the phase curve. Similarly, numerous studies in the literature work on robustness achievement by loop shaping the phase curve of the Bode plot. However, the frequency frame approach is a new perspective in controller tuning. Two examples are illustratively given to prove the proposed method. Plants in the examples are also considered to be due to load disturbances. Simulation results and effects of the method are clearly explained.
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    Fractional order proportional derivative control for time delay plant of the second order: The frequency frame
    (Pergamon-Elsevier Science Ltd, 2020) Senol, Bilal; Demiroglu, Ugur; Matusu, Radek
    This paper intends to tune fractional order proportional derivative controller for the performance, stability and robustness of second order plus time delay plant. The tuning method is based on the previously proposed frequency frame which is a rectangular frame enclosing gain and phase margins limited with gain and phase crossover frequencies in the Bode plot. Edges of the frame are tuned to achieve desired crossover frequencies and margins. By shaping the curves of the Bode plot, improvements are observed in the performance and robustness of the second order plus time delay system controlled by a fractional order proportional derivative controller. Generalized equations to obtain the parameters of the fractional order proportional derivative controller for second order plus time delay plant are given. In contrast to existing studies, this method reduces mathematical complexity when providing desired properties. Three examples are considered and effectiveness of the frequency frame is shown. (c) 2020 The Franklin Institute. Published by Elsevier Ltd. All rights reserved.
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    Frequency frame approach on loop shaping of first order plus time delay systems using fractional order PI controller
    (Elsevier Science Inc, 2019) Senol, Bilal; Demiroglu, Ugur
    This study proposes an analytical design method of fractional order proportional integral (FOP!) controllers for first order plus time delay (FOPTD) systems. Suggested technique obtains the general computation equations of controllers for such systems. These equations are used to tune controller parameters to meet specified frequency and phase properties to satisfy the stability of whole system. It is found that the designed controllers not only make the system stable, but also have positive effect on the performance and robustness of the system. Main contribution of the paper lays on this thought. There proposed a concept, frequency frame which encloses the curves between phase and gain crossover frequencies in Bode plot. Robustness of the control system can be improved by expanding or constricting the edges of this frame and flattening the curves inside the frame. Thus, any case that leads the system to instability can be avoided. Analytically derived equations are tested with proper examples and the results are shown illustratively. Advantages and disadvantages of the method are comparatively given. (C) 2018 ISA. Published by Elsevier Ltd. All rights reserved.
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    Frequency frame approach on tuning FOPI controller for TOPTD thermal processes
    (Elsevier Science Inc, 2021) Demiroglu, Ugur; Senol, Bilal
    The frequency frame is used to tune fractional order proportional-integral controllers for stability, performance and robustness of third order plus time delay plants. Such plants are frequently used in describing thermal processes such as an air heater or a fired boiler. The aim is to tune the controller to meet some frequency domain properties. As robustness is an indispensable issue for thermal processes, main inspiration of the paper comes from flattening the phase curve in the Bode plot to provide improved robustness for the system. In spite of some existing studies, flattening is not realized by equalizing the phase derivative to zero at a given frequency value. Firstly, gain and phase crossover frequency points are enclosed with a rectangular frame. Then, lengths of the edges of this frame are changed to tune phase and gain margins. Curves inside the frame can be flattened by proper tuning of the edges. This will enhance the robustness and also ensure the iso-damping property. Equations to obtain the controller are given with two theorems. Demonstrations are made on two different thermal plants which are a novel electrical air heater and a bagasse fired boiler and the results are given on detailed illustrations. The results proved that preferred gain and phase properties are successfully obtained and improved performance and robustness are provided for related systems. (c) 2020 ISA. Published by Elsevier Ltd. All rights reserved.
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    On the Effects of the Frequency Frame on DC Motor Example: Fractional Order PI-PD Case
    (Ieee, 2019) Demiroglu, Ugur; Senol, Bilal; Matusu, Radek
    This is a comparative study investigating the effects of the controller design method, frequency frame on a DC motor example. Both fractional order proportional integral and proportional derivative controllers are designed for mentioned example which is a first order plus time delay model. The two controllers are in different structures in that they can show different behaviors. The frequency frame approach is a frequency domain method which intends to provide the objective system improved stability and robustness by shaping the Bode curves. In contrary to existing similar methods, shaping is done by a graphical point of view, not by complicated mathematical operations. The reason why a fractional order controller is selected comes from the necessity of a common constant. The study in the paper aims to show the effectiveness of the frequency frame by providing desired frequency specifications with different controllers. Both controllers are calculated for a DC motor transfer function and the comparative results are given.
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    Tuning of PI? Controllers for FOPTD Plants via the Stability Boundary Locus
    (Ieee, 2018) Demiroglu, Ugur; Matusu, Radek; Senol, Bilal
    This study intends to present the systematic design procedure of stabilizing fractional order proportional integral controllers for first order plus time delay (FOPTD) plants via the stability boundary locus (SBL) method. Proposed method gives generalized computation equations for tuning related controllers within desired frequency ranges. Besides, equations to compute the real root boundary (RRB) of the SBL are presented. In spite of the classical design technique, this paper proposes to find the starting and ending points and the stability region of the stability boundary of the system by heuristic approach. This method ensures the stability by analytically obtained formulas instead of testing the regions of the SBL with arbitrary selected points. This proves the advantage and the contribution of the proposed procedure. Obtained equations are applied on examples and the results are illustratively given. Comparisons with the literature showed the effectiveness of the proposal.