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    2781. Model Reaching Adaptive-Robust Control Law For Vibration İsolation Systems With Parametric Uncertainty
    (Journal of Vibroengineering, 2018) Burkan, Recep; Ozguney, Ömur Can; Ozbek, Cengiz
    Adaptive control has been used for active vibration isolation and vehicle suspensions systems. A model reference adaptive control law is used for the plant to track the ideal reference model. In a model reaching adaptive control approach, the ideal of a skyhook target without using a reference model is achieved. In this paper, a novel approach, a model reaching adaptive-robust control law is studied for active vibration isolation systems. A dynamic manifold for ideal system is defined using the ideal of a skyhook target model system parameters. First, a new Lyapunov function is defined. Based on the Lyapunov stability theory, a model reaching adaptive and a robust control laws are derived for the uncertain system to reach the ideal manifold. Parameters and upper bounding functions are estimated as a trigonometric function depending on the relative displacements, velocities and the defined manifold. The developed adaptive and the robust compensators are combined and this combination is proposed as an adaptive-robust control law. After that, the controller is applied to a vehicle suspension system and the ideal of a skyhook target without using a reference model is achieved. The results also show that the proposed robust control law can increase the comfort of the vehicle active suspension systems and the ride comfort is remarkably increased.
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    Design of a fuzzy robust-adaptive control law for active suspension systems
    (Springer India, 2020) Ozbek, Cengiz; Ozguney, Omur Can; Burkan, Recep; Yagiz, Nurkan
    This paper outlines a new approach in control of active vibration systems to make the system robust to parametric uncertainties, unmodeled dynamic effects and external disturbances. Namely, it is aimed to ensure robustness of the system towards all kind of disturbances such as road surface inputs and unexpected system parameter changes. So, a new robust-adaptive controller is designed as a vibration isolator and then applied on a full car active suspension system to improve the ride comfort of a vehicle in the presence of structured parameter uncertainties and unstructured unknown parameters or unmodeled dynamics. For this purpose, new parametric uncertainty upper bound adaptation algorithm is developed to isolate any platform from vibrations. Using adaptive laws, the controller can operate properly under changing conditions. The robustness of controller is also ensured by robust control law. This new approach represents a groundbreaking solution to eliminate any disturbance on a vehicle. Stability of the system is guaranteed by using Lyapunov theory, thus uniform boundedness error convergence is achieved. Afterwards, fuzzy logic controller is used to achieve the optimum values of controller gains. Also, comparative numerical solution using a fuzzy logic controlled suspension is performed on the same full-car model, both in time and frequency domain since classical FLC is an effective control method for active suspensions. At the end, it has been verified that the designed fuzzy robust-adaptive controller improves ride comfort more successfully than fuzzy logic one.
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    Fe3O4 supported UiO-66 (Zr) metal-organic framework for removal of drug contaminants from water: fuzzy logic modeling approach
    (Springer Heidelberg, 2023) Cavusoglu, Civan Ferda; Ozcelik, Guelsuem; Ozbek, Cengiz; Ozkara-Aydinoglu, Seyma; Bayazit, Sahika Sena
    The increase in production and consumption of pharmaceuticals and personal care products causes environmental problems. In this study, naproxen and clofibric acid adsorption were studied using Fe3O4-supported UiO-66 (Zr) metal-organic framework (Mag-UiO-66). The adsorption processes were carried out in batch mode at pH value 3.0. The optimum adsorbent quantities, equilibrium periods, pseudo-first-order (PFO), pseudo-second-order (PSO), and intra-particles diffusion kinetic models were calculated. Non-linear Langmuir, Freundlich, Dubinin-Radushkevich (D-R), and Sips isotherm equations were applied to experimental data. Thermodynamic analyses of naproxen and clofibric acid adsorption were also carried out in this study. The Langmuir isotherm q(m) values were found as 14.15 mg/g for naproxen at 308 K and 41.87 mg/g for clofibric acid at 298 K. Both of the adsorption processes were exothermic. MISO (multi-input single-output) fuzzy logic models for removal of both naproxen and clofibric acid adsorptions were designed based on the experimental data to estimate the removal uptake values. It is noteworthy that the results obtained through designed fuzzy logic models matched well with the experimental data and the findings of this study emphasize the validity of designed fuzzy logic models.
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    Ride comfort improvement using robust multi-input multi-output fuzzy logic dynamic compensator
    (Sage Publications Ltd, 2023) Ozbek, Cengiz; Ozguney, Omur Can; Burkan, Recep; Yagiz, Nurkan
    This article aims to improve the ride comfort of a vehicle keeping a satisfactory without road-holding performance by a novel adaptive control method that is insensitive to unknown system dynamics, model parameter changes, external disturbances and without any loss in suspension working space. With this purpose in mind, a new fuzzy integrated model-based adaptive control law for vehicle suspension systems is proposed in this study to improve the ride comfort and to ensure the robustness of system towards unknown model parameters and external disturbances. First, a model-based adaptive control law, which has the robust characteristics is presented. Afterwards, a multi-input multi-output fuzzy logic controller is designed to determine the controller gains dynamically. The stability of controller is ensured by Lyapunov Theory to achieve uniform boundedness error convergence. A 4 degree-of-freedom half-car model with active suspension system is used in this study to assess the performance of the controller. The results are compared among passive, model-based adaptive control law-controlled and novel fuzzy model-based adaptive control law-controlled systems. It has been concluded that fuzzy model-based adaptive control law further attenuates linear and angular motions of the vehicle increasing the ride comfort. The robustness is also verified for vehicle components having different possible parameter values. It is noteworthy that suspension working length returns to its initial position. Thus, the vehicle ride comfort is improved with no suspension working space loss. Finally, the economic feasibility of controllers has been checked in terms of energy consumption.
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    Robust control of vehicle suspension systems with friction non-linearity for ride comfort enhancement
    (Sage Publications Ltd, 2023) Ozbek, Cengiz; Burkan, Recep; Yagiz, Nurkan
    Robust controllers are attracting considerable interest in control of dynamic systems due to their capability of eliminating parameterized or unparameterized uncertainties. Therefore, model based robust control law is proposed in this study for ride comfort enhancement and applied on a 7 degree-of-freedom full-car suspension system with friction non-linearity. Inertia, spring and damping forces of the system are modelled with parameterized uncertainties while friction forces and external disturbances are considered as unmodelled dynamics, namely, unparameterized uncertainties. To better understand the effectiveness of proposed controller, a dry friction model that has non-linear characteristics is used for analysis. Closed-loop stability of the system is achieved by using well-known Lyapunov Stability Theorem. To better evaluate the effect of proposed robust controller on ride comfort enhancement with successful road holding, extensive numerical analysis is performed and the results are compared with those of previous similar controller and passive suspension system. The effectiveness of proposed control method has been confirmed. Consequently, satisfactory results have been obtained proving that the ride comfort of a vehicle that has both parameterized and unparameterized uncertainties has been further improved with reasonable power consumption values for a vehicle in terms of economic viability.