42,031 research outputs found
Törtrendű deriváltak integrálása nemlineáris rendszerek Ăşj lágy számĂtási eljárásokon alapulĂł adaptĂv szabályozásával = Integration of Fractional Order Derivatives in the Adaptive Control of Nonlinear Systems on the Basis of Novel Soft Computing Techniques
A projektben speciális, "Single Input - Single Output" rendszerekre hasonlĂł háromszögeken alapulĂł adaptĂv fixpont transzformáciĂłs szabályozĂłt dolgoztunk ki Ă©s alkalmaztunk nemlineáris paradigmákra (Ball-Beam System, polimerizáciĂłs reakciĂł, hidraulikus munkahenger). A következĹ‘ lĂ©pĂ©s e mĂłdszer robusztus változatának kidolgozása, majd "Multiple Input - Multiple Output" rendszerekre valĂł kĂ©tfĂ©le általánosĂtása volt. A frakcionális deriváltak Caputo fĂ©le alakjábĂłl numerikus közelĂtĂ©ssel bevezettĂĽk a frakcionális derivált három paramĂ©teres változatát Ă©s a "kezdeti Ă©rtĂ©k" helyett a "kezdeti törtĂ©net" fogalmát. Megmutattuk, hogy ez disszipatĂv Ă©s gerjedĹ‘ rendszerek modellezĂ©sĂ©re is alkalmas. E deriváltat felhasználtuk egĂ©sz rendű rendszerek szabályozásának javĂtására Ă©s hipotetikus frakcionális rendszerek modellezĂ©sĂ©re. Kimutattuk, hogy az általunk javasolt adaptĂv szabályozĂł e rendszerekre nehĂ©zsĂ©g nĂ©lkĂĽl alkalmazhatĂł. AdaptĂv szabályozásunkat kĂĽlönfĂ©le egĂ©sz Ă©s törtrendű rendszerek szabályozására alkalmaztuk szimuláciĂłval. SzĂ©les körű szimuláciĂłs vizsgálatokkal kimutattuk a legtipikusabb, Lyapunov fĂĽggvĂ©nyt használĂł adaptĂv mĂłdszerek hiányosságait. VĂ©gĂĽl ezek kikĂĽszöbölĂ©sĂ©re kidolgoztuk a "Model Reference Adaptive Control" szabályozĂłk Ăşj változatát, amely Lyapunov direkt mĂłdszere helyett robusztus fixpont transzformáciĂłval működik. | In the project special adaptive controllers were proposed for "Single Input - Single Output" systems. It applies similar triangles for formulating the control law. It was successfully applied for nonlinear paradigms as the Ball-Beam System, a polymerization reaction, and a hydraulic cylinder. In the next step the robust version of this method was elaborated, it was generalized for "Multiple Input - Multiple Output" systems in two different ways. Via numerically approximating Caputo's definition of fractional order (FO) systems a three parameters, finite memory generalization of the FO derivatives was proposed with the concept of the "preceding history" instaed of the "initial conditions". It was shown that it can be used for modeling stable dissipative and unstable systems, too. The new fractional derivative was utilized for improving the adaptive control elaborated for integer order systems, and for modeling the fractional order systems. It was shown that the fixed point transformations based control can easily be applied for the adaptive control of such hypothetical systems. Our method was applied for various integer and fractional order systems via simulations. The most important deficiencies of the most popular adaptive methods using Lyapunov's direct method were pointed out. To eliminate these deficiencies a novel approach was elaborated for the "Model Reference Adaptive Control" in which Lyapunov's method is replaced by robust fixed point transformation
Adaptive Backstepping Control for Fractional-Order Nonlinear Systems with External Disturbance and Uncertain Parameters Using Smooth Control
In this paper, we consider controlling a class of single-input-single-output
(SISO) commensurate fractional-order nonlinear systems with parametric
uncertainty and external disturbance. Based on backstepping approach, an
adaptive controller is proposed with adaptive laws that are used to estimate
the unknown system parameters and the bound of unknown disturbance. Instead of
using discontinuous functions such as the function, an
auxiliary function is employed to obtain a smooth control input that is still
able to achieve perfect tracking in the presence of bounded disturbances.
Indeed, global boundedness of all closed-loop signals and asymptotic perfect
tracking of fractional-order system output to a given reference trajectory are
proved by using fractional directed Lyapunov method. To verify the
effectiveness of the proposed control method, simulation examples are
presented.Comment: Accepted by the IEEE Transactions on Systems, Man and Cybernetics:
Systems with Minor Revision
A survey on fractional order control techniques for unmanned aerial and ground vehicles
In recent years, numerous applications of science and engineering for modeling and control of unmanned aerial vehicles (UAVs) and unmanned ground vehicles (UGVs) systems based on fractional calculus have been realized. The extra fractional order derivative terms allow to optimizing the performance of the systems. The review presented in this paper focuses on the control problems of the UAVs and UGVs that have been addressed by the fractional order techniques over the last decade
On the validity of memristor modeling in the neural network literature
An analysis of the literature shows that there are two types of
non-memristive models that have been widely used in the modeling of so-called
"memristive" neural networks. Here, we demonstrate that such models have
nothing in common with the concept of memristive elements: they describe either
non-linear resistors or certain bi-state systems, which all are devices without
memory. Therefore, the results presented in a significant number of
publications are at least questionable, if not completely irrelevant to the
actual field of memristive neural networks
The application of a new PID autotuning method for the steam/water loop in large scale ships
In large scale ships, the most used controllers for the steam/water loop are still the proportional-integral-derivative (PID) controllers. However, the tuning rules for the PID parameters are based on empirical knowledge and the performance for the loops is not satisfying. In order to improve the control performance of the steam/water loop, the application of a recently developed PID autotuning method is studied. Firstly, a 'forbidden region' on the Nyquist plane can be obtained based on user-defined performance requirements such as robustness or gain margin and phase margin. Secondly, the dynamic of the system can be obtained with a sine test around the operation point. Finally, the PID controller's parameters can be obtained by locating the frequency response of the controlled system at the edge of the 'forbidden region'. To verify the effectiveness of the new PID autotuning method, comparisons are presented with other PID autotuning methods, as well as the model predictive control. The results show the superiority of the new PID autotuning method
The potential of fractional order distributed MPC applied to steam/water loop in large scale ships
The steam/water loop is a crucial part of a steam power plant. However, satisfying control performance is difficult to obtain due to the frequent disturbance and load fluctuation. A fractional order model predictive control was studied in this paper to improve the control performance of the steam/water loop. Firstly, the dynamic of the steam/water loop was introduced in large-scale ships. Then, the model predictive control with an extended prediction self adaptive controller framework was designed for the steam/water loop with a distributed scheme. Instead of an integer cost function, a fractional order cost function was applied in the model predictive control optimization step. The superiority of the fractional order model predictive control was validated with reference tracking and load fluctuation experiments
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