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  • Küçük Resim
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    Minimal controller synthesis algorithms with output feedback and their generalization
    (Tubitak Scientific & Technical Research Council Turkey, 2013) Sevinc, Ata
    This paper proposes several improvements in the minimal controller synthesis algorithms, which were developed for a class of nonlinear systems with uncertainties. The major proposition is that only the output feedback is enough to control some nonlinear systems without an observer while the existing algorithms require the complete state feedback. Next, the extended version and the parameter identification technique of the minimal controller synthesis algorithm are combined in a single method estimating some more parameters for some known forms of nonlinearities. This is applicable with or without the improvement of removing the need for using the complete state feedback. It is proven that the scaling factors in the algorithms can be variable and different for each component. The algorithms are applicable to some noncanonical forms of systems. All the propositions and some of the existing algorithms are generalized in a single form with some options. A speed-sensorless DC motor control simulation is also included with quite exaggerated noisy conditions and the results verify that the proposed modifications make the minimal controller synthesis algorithms much more efficient model reference adaptive control algorithms for certain types of systems. The proposed method, which does not use the speed measurement, yields fewer ripples than the existing method, which uses the speed measurement. In addition, the proposed method accurately estimates the armature resistance and inductance while the existing method fails to do this.
  • Küçük Resim
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    Model Parameters of Electric Motors for Desired Operating Conditions
    (Univ Suceava, Fac Electrical Eng, 2019) Sevinc, Ata
    Researchers dealing with electric motor control simulations need motor parameters for some desired operating conditions. Despite such an obvious need, no algorithm yielding motor parameters can be found even for the basic set of desired "voltage, output power, speed and efficiency" in the literature. A lot of electric motor design methods exist; but all give the physical design parameters for manufacturing such as numbers and dimensions of slots, magnets and turns. They are usually based on design requirements that only experienced people can understand and the mentioned basic demand set is not completely included among them. This article covers the deficiency of the algorithms giving all the model parameters required for the control simulations for dc servo, induction, and synchronous motors according to simple design requirements that an inexperienced researcher can easily understand. A transformer design algorithm is also included. The induction motor and salient-pole synchronous motor algorithms are the main contributions. The propositions can be used even if the demands are given for generator mode with some care. These algorithms may also be considered as another kind of design and they may help to reduce physical designs to lower-level steps according to simple design requirements.
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    Öğe
    Ultrasonic Therapy Device Using Fuzzy-Logic for Clinical Use
    (Kırıkkale Üniversitesi, 2023) Yalçınkaya, Fikret; Sevinc, Ata; Aydilek, Hüseyin; Erbaş, Ali
    In this paper, an ultrasonic therapy device using fuzzy-logic(UTD-FL) has been designed, constructed and tested with phantom materials. Fuzzy-logic rules have been determined using four parameters. In clinical practice, ultrasonic therapy is conducted solely based on subjective evaluation of medical experts, but in UTD-FL, fuzzy-logic rules decide automatically the three critically important characteristic parameters of applicable output power to the patient, namely the power of the signal, the percent of the duty-cycle and the signal frequency. The signal frequency and specifically its amplitude have critical effect on the temperature rise of the tissue test-point or surface. Therefore the intensity of the ultrasonic frequency and the duration of treatment-time are absolutely vital, that is why this instrument has been developed. This instrument is expected to prevent possible side effects, injuries, and potential damages on real tissues due to experts’ uneasiness. The test results of this newly developed medical device have been compared with clinical-practice. The instrument produces optimum output power due to its fuzzy-logic rules based mode design, and IR-temperature sensor based feedback effect; whereas the clinical mode inputs only clinical experience base gained medical data.