29 research outputs found

    Generalized Hamilton-Jacobi equations for nonholonomic dynamics

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    Employing a suitable nonlinear Lagrange functional, we derive generalized Hamilton-Jacobi equations for dynamical systems subject to linear velocity constraints. As long as a solution of the generalized Hamilton-Jacobi equation exists, the action is actually minimized (not just extremized)

    Exact controllability of non-Lipschitz semilinear systems

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    We present sufficient conditions for exact controllability of a semilinear infinite-dimensional dynamical system. The system mild solution is formed by a noncompact semigroup and a nonlinear disturbance that does not need to be Lipschitz continuous. Our main result is based on a fixed point-type application of the Schmidt existence theorem and illustrated by a nonlinear transport partial differential equation

    Flache Konvexit盲t von Orliczr盲umen

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    Lagrange Lemma and the optimal control of diffusions II : nonlinear Lagrange functionals

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    In (Kosmol, 1991; Kosmol and Pavon, 1993) a new elementary approach to optimal control problems relying on the Lagrange lemma was described which appears to be technically, and conceptually, much simpler than existing methods, and, furthermore, provides a unified variational approach. In (Kosmol and Pavon, 1992) this method was further clarified and developed for linear Lagrangefunctionals. We devote this second paper to nonlinear Lagrangefunctionals. The power of this approach is here clearly demonstrated. In particular, it is shown that the nonlinear Lagrange functional induced by the value function of the problem is just one of the many functionals which may effectively be employed to solve control problems, see Examples 1 and 2 in Section 3. Moreover, in our approach, we can deal in the same framework with problems with state constraints, or nonsmooth problems. Hence, the Lagrange functionals approach provides new tools to solve control problems which may be readily applied even when existing approaches fail

    Comparision of optimisation methods basing on primitives and initiall geometric models

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    W artykule przedstawiono por贸wnanie dw贸ch metod optymalizacji korpus贸w maszyn. Obie metody wykorzystuj膮 zar贸wno metod臋 element贸w sko艅czonych jak i algorytm ewolucyjny. Pierwsza z nich zak艂ada, 偶e znany jest model wst臋pny obiektu i w贸wczas nale偶y u偶y膰 tylko optymalizacji parametrycznej. Natomiast w drugim przypadku, kiedy nie ma 偶adnych informacji o modelu obiektu nale偶y zastosowa膰 zar贸wno optymalizacje topologiczn膮 jak i parametryczn膮. Ta druga metoda wykorzystuje prymitywy, jako modele wst臋pne obiektu. W artykule zamieszczono wyniki por贸wnania obu metod dla wybranego korpusu obrabiarki. Por贸wnaniu podlega艂y optymalne rozwi膮zania w postaci: wska藕nik贸w sztywno艣ci, ich rozrzutu, masy korpus贸w i cz臋stotliwo艣膰 drga艅 w艂asnych. Wyniki tych por贸wna艅 s膮 dosy膰 oczywiste: metoda optymalizacji, bazuj膮ca na prymitywach daje korzystniejsze efekty ni偶 metoda bazuj膮ca na projekcie wst臋pnym. Dotyczy to w szczeg贸lno艣ci masy zoptymalizowanego korpusu, kt贸ra mo偶e by膰 nawet o 10 mniejsza.The paper presents comparison of two optimisation methods of machine frames. Both methods use Finite Element Methods and Evolutionary Algorithm simultanously. The first of the method assumes that the initail model of the body is known and in such situation the parametric optimisation should be applied only. In the second case when one has no information about the object鈥檚 model, the Topology optimisation and Parametric optimisation should be applied. The second method uses Prymitives as preliminary model of object. The paper presents results of comparision of both metof applied to an example frame. Such parameters were compared: coefficients of stiffness, dispersion of stiffness, masses od frames, free frequency of vibration. Results of comparision are very obviousness: method of optimisation based on primitives gives better results than method based on initialy project. First of all it concerns on the mass of opimised frame, which may be even 10% smaller

    Solving optimal control problems by means of general Lagrange functionals

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    The method of Lagrange functionals is applied to the optimal control of systems with quadratic and implicit dynamics

    Lagrange Approach To the Optimal-control of Diffusions

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    A new approach to the optimal control of diffusion processes based on Lagrange functionals is presented. The method is conceptually and technically simpler than existing ones. A first class of functionals allows to obtain optimality conditions without any resort to stochastic calculus and functional analysis. A second class, which requires Ito's rule, allows to establish optimality in a larger class of problems. Calculations in these two methods are sometimes akin to those in minimum principles and in dynamic programming, but the thinking behind them is new. A few examples are worked out to illustrate the power and simplicity of this approach

    Experimental verification of polymer concrete frames

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    W artykule przedstawiono wst臋pne wyniki bada艅 eksperymentalnych korpusu belki suportowej niewype艂nionej i wype艂nionej polimerobetonem w postaci odpowiedzi impulsowej i charakterystyk widmowych. Celem tych bada艅 by艂a ocena poprawy niekt贸rych w艂a艣ciwo艣ci dynamicznych korpus贸w obrabiarek, poprzez wype艂nienie ich polimerobetonem.The paper presents preliminary experimental results of a machine tool beam filled up and not filled up with Polymer Concrete (PC) as a transient response and amplitude spectrum. The main goal of the experiments was evaluation of improving selected dynamic properties of machine tool frames through filled them Polymer Concrete

    Bemerkungen zur brachistochrone

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