Yazar "Arican, Ahmet Cagri" seçeneğine göre listele

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    Adaptive Control of a 3 DoF Helicopter with Linear and Nonlinear Reference Models
    (IEEE, 2018) Kocagil, Bedrettin Mahmut; Ozcan, Sinan; Arican, Ahmet Cagri; Guzey, Umit Mufit; Copur, Engin Hasan; Salamci, Metin U.
    Adaptive control methods are widely used for the control of both linear and nonlinear dynamical systems. Among the adaptive control approaches, Model Reference Adaptive Control (MRAC) method has a systematic design feature in which response of a stable reference model is targeted to be followed by the dynamical system. In general, Linear Time Invariant (LTI) Reference Models are considered in the MRAC design and the adaptation rule is formulated accordingly. In this paper, the linear reference model is altered with a stable nonlinear one and the adaptation rule is re-formulated to cope with the nonlinearity. The stable nonlinear reference model is generated by using the State Dependent Riccati Equation (SDRE) approach and the adaptation rule is also updated by using the same SDRE idea. The effects of altering the linear reference model to the nonlinear counterpart are shown in the MRAC formulations. In addition to the new MRAC formulations, the proposed MRAC algorithm is applied to a 3 DoF helicopter test bed to reveal the advantages of the nonlinear reference model.
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    An Extension Algorithm of Regional Eigenvalue Assignment Controller Design for Nonlinear Systems
    (Mdpi, 2023) Arican, Ahmet Cagri; Copur, Engin Hasan; Inalhan, Gokhan; Salamci, Metin Uymaz
    This paper provides a new method to nonlinear control theory, which is developed from the eigenvalue assignment method. The main purpose of this method is to locate the pointwise eigenvalues of the linear-like structure built by freezing the nonlinear systems at a given time instant in a desired disk region. Since the control requirements for the transient response characteristics are the major constraints on the selection of the disk centre and radius, two different update algorithms are also developed to reshape the disk region by changing the disk centre and radius at each time step. The effectiveness of the proposed methods is tested in both simulations and experiments. A validated three-DOF laboratory helicopter is used for experiments.
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    Linear and Nonlinear Optimal Controller Design for a 3 DOF Helicopter
    (IEEE, 2018) Arican, Ahmet Cagri; Ozcan, Sinan; Kocagil, Bedrettin Mahmut; Guzey, Umit Mufit; Copur, Engin Hasan; Salamci, Metin Uymaz
    The paper presents the application of State-Dependent Riccati Equation (SDRE) based optimal control for a nonlinear system. The performance of linear control methods in controlling nonlinear systems is inconsistent due to their inability to adapt themselves to the varying operating conditions of nonlinear systems. This stubborn feature of linear control methods limits their control performance. However, SDRE technique offers a flexible design to obtain an optimal control strategy, thereby accounting for the varying operating conditions. With the existence of this flexibility, SDRE control method has attracted a lot of interest in controlling nonlinear systems. A 3-DOF laboratory helicopter is thus used to investigate experimentally the performance of the proposed SDRE control method in tracking the reference motions in both travel and elevation axes. To establish the feasibility of the SDRE control method, it is compared with the well-known Linear Quadratic Regulator (LQR) control method in terms of the cost function value. Results show that SDRE control method is more effective than LQR one.
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    State Dependent Regional Pole Assignment Controller Design for a 3-DOF Helicopter Model
    (IEEE, 2023) Arican, Ahmet Cagri; Copur, Engin Hasan; Inalhan, Gokhan; Salamci, Metin U.
    For linear systems, a state feedback control law can be easily designed to keep all closed-loop poles inside a specified disk since the locations of the poles are unique. However, its application to nonlinear systems is not so simple. Therefore, this paper introduces a new pole placement method, named as State Dependent Regional Pole Assignment, for nonlinear systems. This proposed method produces a state dependent feedback control law, enabling the eigenvalues of the closed-loop matrix to be placed in a specified disk to achieve the desired control performance characteristics. The effectiveness of the method is tested on the 3 DOF Helicopter experimental setup. To verify its effectiveness, the experimental results of the nonlinear method are compared with those of the linear method.