56 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
Irodalmi kommunikáció és értékrend (A görög értékrend alakulása különös tekintettel a hellenisztikus korra. A római mos maiorum az Augustus-kortól a patrisztikus korig.) = Literary communication and system of values. (The formation of Greek values especially in the Hellenistic Age. The Roman mos maiorum from the age of Augustus until the patristic age.)
Az irodalmi Ă©rtĂ©krend Ă©s kommunikáciĂł kĂ©rdĂ©sĂ©t a pályázatban rĂ©sztvevĹ‘k a következĹ‘ irodalmi korszakokban vizsgálták: a./ korai görög lĂra - iambos, kitekintĂ©ssel a hellenisztikus korra Ă©s a rĂłmai lĂrára, valamint a humanista latin nyelvű irodalomra. Az iambos mint a Ă©rtĂ©krend kifejezĂ©sre juttatĂłja. b./ rĂłmai aranykor - Ă©rtĂ©kfogalmak Cicero PartitionesĂ©ben. Vergilius, Horatius, Ovidius művei Ă©s az Augustusi propaganda; utĂłbbi más mĂ©diumokban (ikonográfia, numizmatika) valĂł kifejezĹ‘dĂ©se. c./ császárkori epika - a közĂ©ppontban Lucanusszal. A korábbi Ă©rtĂ©krendhez valĂł viszony. d./ kĂ©sei császárkor - a vegyesházasságok kapcsán a házassággal kapcsolatos fogalmak helye a pogány Ă©s keresztĂ©ny Ă©rtĂ©krendben. Az antiszemitizmus kĂ©rdĂ©se a CTh 3,7,2 vizsgálata alapján. EredmĂ©ny: 46 tĂ©tel (disszertáciĂłk, tanulmányok, adatbázisok, elĹ‘adások) | The problem of the literary scale of values and that of literary communication has been examined in the following literary periods: a./ early Greek iambos, with outlook to the hellenistic period, to the Latin poetry and to the humanistic Latin literature. Tha iambos as expression of the scale of values. b./ Roman golden age - concept of values in the Partitiones by Cicero. The works of Vergile, Horace and Ovid and the Augustan propaganda; expression of the augustan propaganda in other media (iconography, numismatics). c./ Roman epics of the 1. c. A.D. - in the centre with Lucan. Relation of values to the earlier value-system. d./ later imperial centuries - part of the ideas connected with the matrimony with reference to the mixed matrimonies in the pagan and Christian scale of values. The problem of antisemitism on examination of CTh 3,72. Results: 46 theses (dissertations, essays, databases, papers
Robust Fixed Point Transformations in Adaptive Control Using Local Basin of Attraction
A further step towards a novel approach to adaptive nonlinear control developed
at Budapest Tech in the past few years is reported. This approach obviates the use of the
complicated Lyapunov function technique that normally provides global stability of
convergence at the costs of both formal and essential restrictions, by applying Cauchy
sequences of local, bounded basin of attraction in an iterative control that is free of such
restrictions. Its main point is the creation of a robust iterative sequence that only slightly
depends on the features of the controlled system and mainly is determined be the control
parameters applied. It is shown that as far as its operation is considered the proposed
method can be located between the robust Variable Structure / Sliding Mode and the
adaptive Slotine-Li control in the case of robots or other Classical Mechanical Systems.
The operation of these method is comparatively analyzed for a wheel + connected mass
system in which this latter component is “stabilized” along one of the spokes of the wheel
in the radial direction by an elastic spring. The robustness of these methods is also
investigated againts unknown external disturbances of quite significant amplitudes. The
numerical simulations substantiate the superiority of the robust fixed point transformations
in the terms of accuracy, simplicity, and smoothness of the control signals applied.N/
Preliminary Sketch of Possible Fixed Point Transformations for Use in Adaptive Control
In this paper a further step towards a novel approach to adaptive nonlinear control developed at Budapest Tech in the past few years is reported. Its main advantage in comparison with the complicated Lyapunov function based techniques is that it is based on simple geometric considerations on the basis of which the control task can be formulated as a Fixed Point Problem for the solution of which a Contractive Mapping is created that generates an Iterative Cauchy Sequence for Single Input - Single Output (SISO) systems. Consequently it converges to the fixed point that is the solution of the control task. In the formerly developed approaches for monotone increasing or monotone decreasing systems the proper fixed points had only a finite basin of attraction outside of which the iteration might become divergent. The here sketched potential solutions apply a special function built up of the “response function” of the excited system under control and of a few parameters. This function has almost constant value apart from a finite region in which it has a “wrinkle” in the vicinity of the desired solution that is the “proper” fixed point of this function. By the use of an affine approximation of the response function around the solution it is shown that at one of its sides this fixed point is repulsive, while at the opposite side it is attractive. It is shown, too, that at the repulsive side another, so called “false” fixed point is present that is globally attractive, with the exception of the basin of attraction of the “proper” one. This structure is advantageous because a) no divergence can occur in the iteration, b) the convergence to the “false” value can easily be detected, and c) by using some ancillary tricks in the most of the cases the solution can be kicked from the wrong fixed point into the basin of attraction of the “proper one”. In the paper preliminary calculations are presented.N/
Simple Kinematic Design for Evading the Forced Oscillation of a Car-Wheel Suspension System
An adaptive control damping the forced vibration of a car while passing
along a bumpy road is investigated. It is based on a simple kinematic description
of the desired behavior of the damped system. A modified PID controller containing
an approximation of Caputo’s fractional derivative suppresses the high-frequency
components related to the bumps and dips, while the low frequency part of passing
hills/valleys are strictly traced. Neither a complete dynamic model of the car nor ’a
priori’ information on the surface of the road is needed. The adaptive control realizes
this kinematic design in spite of the existence of dynamically coupled, excitable
internal degrees of freedom. The method is investigated via Scicos-based simulation
in the case of a paradigm. It was found that both adaptivity and fractional order
derivatives are essential parts of the control that can keep the vibration of the load at
bay without directly controlling its motion
Improved Numerical Simulation for a Novel Adaptive Control Using Fractional Order Derivatives
A novel control technique is investigated in the adaptive control of a
typical paradigm, an approximately and partially modeled cart plus double pendulum
system. In contrast to the traditional approaches that try to build up ”complete”
and ”permanent” system models it develops ”temporal” and ”partial” ones that are
valid only in the actual dynamic environment of the system, that is only within some
”spatio-temporal vicinity” of the actual observations. This technique was investigated
for various physical systems via ”preliminary” simulations integrating by the
simplest 1st order finite element approach for the time domain. In 2004 INRIA issued
its SCILAB 3.0 and its improved numerical simulation tool ”Scicos” making it possible
to generate ”professional”, ”convenient”, and accurate simulations. The basic
principles of the adaptive control, the typical tools available in Scicos, and others
developed by the authors, as well as the improved simulation results and conclusions
are presented in the contribution
Scicos Based Investigation of an Adaptive Vibration Damping Technique Using Fractional Order Derivatives
Detailed investigation of a simple nonlinear, active, adaptive approach of controlling the oscillation of a car proceeding on a bumpy road is presented. Its key idea is a frequency dependent control of the strictness of a traditional PID controller by applying fractional order derivatives in a simple kinematic design without any respect to the dynamic model of the system. The adaptive part of the controller relieves the designer of dealing with the system’s dynamics within the frames of some linear control, and guarantees the implementation of this design. The operation of the approach is illustrated by the use of INRIA’s scientific co-simulator Scicos for a rough model of a car. Well interpretable trends were revealed regarding the effect of the variation of the order of derivation, and that of the sampling time of the adaptive loop. These results seem to be promising for actively damping the vibration of systems having unmodeled, uncontrolled internal degrees of freedom.N/
Adaptive nonlinear vibration damping inspired by the concept of fractional derivatives
In this paper a simple nonlinear, adaptive approach inspired by the CRONE method is presented for vibration control. It replaces the fractional derivatives with time-invariant Green functions. Being completed by a nonlinear feedback term it makes the positive definite weighted moving average of the square of the error converge to zero in the kinematic design of the desired damping the realization of which is guaranteed by the controller's adaptive nature. The burden of designing a sophisticated linear controller is evaded. The applicability of the approach is illustrated via simulations for a damped linear oscillator under external excitation at its resonance frequency. The adaptive loop simply successively maps the observed system behavior to the desired one without exerting any effort to identify the reasons of the differences. It is expected to be useful for solving even more complicated vibration damping problems with unmodeled and uncontrolled internal degrees of freedom.N/
Adaptive nonlinear vibration control based on causal time-invariant green functions and on a novel branch of soft computing
In this paper a simple nonlinear, adaptive approach inspired by the fractional derivatives based CRONE control is presented for vibration damping. Its key idea is replacement of the fractional derivatives with the mathematically less restricted concept of time-invariant Green functions. Instead of the traditional PID feedback terms it applies positive definite weighted moving average of the square of the error plus a nonlinear term making the error converge to zero. In this way simple kinematic design of the desired damping becomes possible. The adaptive part of the controller guarantees the realization of this kinematic design without making it necessary to the designer to have an accurate and complete dynamic model of the system to be controlled or to design sophisticated linear controller. The applicability of the approach is illustrated via simulations for a paradigm consisting of a pair of coupled damper linear oscillators under external excitation. One of the oscillators is not modeled by the controller. The adaptive loop successively maps the observed system behavior to the desired one without exerting any effort to identify the reasons of the differences. The approach was found be useful for solving vibration damping problems with unmodeled and uncontrolled internal degrees of freedom.N/
A kis lilik (Anser erythropus L.) és közel rokon nagytestű lúdfajok magterjesztésben betöltött szerepe és élőhelyi preferenciája a Hortobágyi Nemzeti Parkban
Az állatok általi magterjesztĂ©snek igen jelentĹ‘s szerepe van a növĂ©nyi elterjedĂ©si mintázatok kialakĂtásában. Ăšjabb kutatások kimutatták, hogy a vĂzimadarak is igen jelentĹ‘s szerepet tölthetnek be a növĂ©nyi magterjesztĂ©sben. A zoochor magterjesztĂ©s vizsgálatával egyrĂ©szt megĂ©rthetjĂĽk az állati terjesztĹ‘ vektorok szerepĂ©t a növĂ©nyi terjedĂ©sben, másrĂ©szt fontos informáciĂłkat nyerhetĂĽnk az állatok táplálĂ©k-összetĂ©telĂ©rĹ‘l. Vizsgálatunk cĂ©lja a fokozottan vĂ©dett Ă©s globálisan veszĂ©lyeztetett kis lilik (Anser erythropus L.) illetve a hasonlĂł Ă©lĹ‘helyeket használĂł nagyobb testű ludak (nyári lĂşd – Anser anser L. Ă©s nagy lilik – Anser albifrons Scop.) endozoochor magterjesztĂ©sĂ©nek Ă©s Ă©lĹ‘hely-preferenciájának vizsgálata volt. A vizsgálatot a LIFE10-NAT/GR/000638 projekt támogatta. Az ĂĽrĂĽlĂ©kmintákat a Hortobágyi Nemzeti Park terĂĽletĂ©n gyűjtöttĂĽk, ahol a kis lilikek Ă©s a nagyobb testű ludak tavaszi Ă©s Ĺ‘szi vonulásuk során táplálkoznak. A vizsgálatban azonosĂtottuk a ludak fĹ‘bb táplálkozĂł-terĂĽleteit, ahonnan összesen 720 ĂĽrĂĽlĂ©k-mintát gyűjtöttĂĽnk mind a kis lilik mind a nagyobb testű ludak ĂĽrĂĽlĂ©kĂ©bĹ‘l 2012 tavaszán Ă©s Ĺ‘szĂ©n. A mintákat mosással koncentráltuk, majd sterilizált virágföldet tartalmazĂł csĂráztatĂł ládákban, ĂĽvegházban csĂráztattuk. Ă–sszesen 21 faj egyedeit sikerĂĽlt kicsĂráztatni a ludak ĂĽrĂĽlĂ©kĂ©bĹ‘l. Vizsgálatunkban jelentĹ‘s Ă©vszakos kĂĽlönbsĂ©geket találtunk mind a kis lilik mind a nagyobb testű ludak ĂĽrĂĽlĂ©kĂ©bĹ‘l csĂrázĂł magok mennyisĂ©gĂ©ben Ă©s fajszámában: az Ĺ‘szi mintákbĂłl több fajt Ă©s több csĂranövĂ©nyt mutattunk ki. Vizsgálatunkban kimutattuk, hogy mĂ©g közel rokon, hasonlĂł Ă©lĹ‘helyeken táplálkozĂł lĂşdfajok esetĂ©ben is jelentĹ‘s kĂĽlönbsĂ©gek lehetnek a fajok magterjesztĹ‘ kĂ©pessĂ©gĂ©ben. EredmĂ©nyeink alapján a kis lilik erĹ‘sen kötĹ‘dik a termĂ©szetes, jĂł állapotĂş szikes gyepekhez Ă©s szikes rĂ©tekhez, mivel ilyen Ă©lĹ‘helyeken voltak a fĹ‘bb táplálkozĂł-terĂĽletek. A kis lilik ĂĽrĂĽlĂ©kĂ©bĹ‘l nagyobb egyedszámban Ă©s fajszámban csĂráztak a szikes Ă©lĹ‘helyekre jellemzĹ‘ fajok magjai, ugyanakkor kisebb egyedszámban Ă©s fajszámban csĂráztak a gyomfajok. Ă–sszesen 21 faj csĂrakĂ©pes magját sikerĂĽlt kimutatnunk az ĂĽrĂĽlĂ©kmintákbĂłl, ami arra utal, hogy a ludak jelentĹ‘s szerepet tölthetnek be mind a gyepi mind a vizes Ă©lĹ‘helyekre jellemzĹ‘ fajok magjainak terjesztĂ©sĂ©ben.</jats:p
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