Yazar "Bolat, Fevzi Cakmak" seçeneğine göre listele

Listeleniyor 1 - 3 / 3
  • Küçük Resim Yok
    Öğe
    Active vibration control of a blade element with uncertainty modeling in PZT actuator force
    (Sage Publications Ltd, 2019) Sivrioglu, Selim; Bolat, Fevzi Cakmak; Erturk, Ercan
    The aim of this research is to attenuate the vibrations of a blade structure with an attached piezoelectric actuator using robust multi-objective control. The force obtained from a piezoelectric patch loading has uncertainties due to the complicated shape (airfoil) of the blade element. A parameter-dependent model of the force equation is developed to understand the possible variation range of the actuation force. The modal analysis of the blade is performed to find vibration mode frequencies, and an aerodynamic load is generated experimentally to create steady-state vibration on the blade. A state-space model is obtained by considering certain vibration modes and the parameter-dependent part of the force in the input vector is taken outside of the plant model. The robust stability filter is modified with parameter dependency to have a cluster of the filter. Two different multi-objective controllers are designed with different design objectives. The designed controllers are implemented in experiments and performances of the controllers are compared using frequency and time domain responses. It is shown that the flexible blade vibrations are successfully suppressed with the proposed mixed norm robust controllers under the effect of steady-state aerodynamic disturbance with different air speeds. It is observed in experimental results that the performances of the H infinity/H2controller are better than theH2/H infinity controller.
  • Küçük Resim Yok
    Öğe
    Piezoelectric and electromagnetic hybrid energy harvesting with low-frequency vibrations of an aerodynamic profile under the air effect
    (Academic Press Ltd- Elsevier Science Ltd, 2019) Bolat, Fevzi Cakmak; Basaran, Sinan; Sivrioglu, Selim
    In this study, a novel hybrid energy harvesting system consisting of a piezoelectric material and an electromagnetic induction device is experimentally inevstigated. Flow-induced vibrations can be considered as an aerodynamics air effect and can be converted to electrical energy. By connecting an airfoil profile to a beam element, vibrations are occurred on the proposed structure by creating an aerodynamic air effect. This aerodynamic air effect is controlled by using an Arduino board with a solenoid valve connected to the air line. A piezoelectric transduction is attached on the beam, and an electromagnetic-Lorentz induction is connected to the airfoil element at the end of this beam. Energy is simultaneously harvested by using electromagnetic induction and piezoelectric transduction with respect to the vibration motion of the beam. Within the scope of the study, the amount of energy obtained using the piezoelectric material and Lorentz actuator by connecting resistors of different sizes are measured with an oscilloscope. The experimental results show that the amount of energy obtained from the proposed structure is at promising levels that can be used to run small electronic units which commonly used in aerospace applications. (C) 2019 Elsevier Ltd. All rights reserved.
  • Küçük Resim Yok
    Öğe
    Switching linear quadratic Gaussian control of a flexible blade structure containing magnetorheological fluid
    (Sage Publications Ltd, 2020) Sivrioglu, Selim; Bolat, Fevzi Cakmak
    The present study suggests a new active control structure with a switching algorithm for control current of the electromagnetic actuator to suppress vibrations of a flexible blade element containing magnetorheological (MR) fluid. An identification model between MR fluid inside the blade and the electromagnetic actuator is utilized to derive the force equation. Since only one electromagnet is employed to suppress the blade vibration, a single-sided control actuation occurs in the proposed system. Therefore, the pulling force used for vibration control is generated by the actuator when the blade moves to downward direction. A switching linear quadratic Gaussian (LQG) controller that produces always a positive control input is designed to attenuate the blade vibrations. The LQG controller with switching is experimentally implemented under the impact and steady-state aerodynamic disturbances. The results of experiments show that the proposed switching controller is effective to attenuate vibrations of the flexible blade element.