Optimal boundary control for the heat equation with application to freezing with phase change

Type: Article
Publication Date: 2013-11-01
Citations: 6
DOI: https://doi.org/10.1109/aucc.2013.6697308

Abstract

In this paper an approach for optimal boundary control of a parabolic partial differential equation (PDE) is presented. The parabolic PDE is the heat equation for thermal conduction. A technical application for this is the freezing of fish in a vertical plate freezer. As it is a dominant phenomenon in the process of freezing, the latent heat of fusion is included in the model. The aim of the optimization is to freeze the interior of a fish block below -18 °C in a predefined time horizon with an energy consumption that is as low as possible assuming that this corresponds to high freezing temperatures.

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  • Duo Research Archive (University of Oslo)
  • Australian Control Conference

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In this paper an optimal control problem for polymer crystallization is investigated. The crystallization is described by a non-isothermal Avrami–Kolmogorov model and the temperature at the boundary of the domain … In this paper an optimal control problem for polymer crystallization is investigated. The crystallization is described by a non-isothermal Avrami–Kolmogorov model and the temperature at the boundary of the domain serves as control variable. The cost functional takes into account the spatial variation of the crystallinity and the final degree of crystallization. This results in a boundary control problem for a parabolic equation coupled with two ordinary differential equations, which is treated by an adjoint variable approach. We prove the existence and uniqueness of solutions to the state system as well as the existence of a minimizer for the cost functional under consideration. The adjoint system is derived and we use a steepest descent algorithm to solve the problem numerically. Numerical simulations illustrate the applicability and performance of the optimization algorithm.
Ранее была рассмотрена задача: на части границы области Ω ⊂ R3 находится нагреватель, имеющий регулируемую температуру. Требуется найти такой режим работы нагревателя, чтобы средняя температура в некоторой подобласти D области … Ранее была рассмотрена задача: на части границы области Ω ⊂ R3 находится нагреватель, имеющий регулируемую температуру. Требуется найти такой режим работы нагревателя, чтобы средняя температура в некоторой подобласти D области Ω принимала заданное значение. В данной работе рассматривается аналогичная задача граничного управления связанная с псевдопараболическим уравнением на отрезке. На части границы рассматриваемого отрезка задается значение решения, которое содержит параметр управления. Ограничение для допустимого управления задано в таком виде, что среднее значение решения в некоторой части рассматриваемого отрезка принимает заданное значение. Решается вспомогательная задача методом разделения переменных. Искомая задача сводится к интегральному уравнению Вольтерра второго рода. Методом преобразования Лапласа доказываются теоремы о существовании и единственности допустимого управления. Previously, a mathematical model for the following problem was considered. On a part of the border of the region Ω ⊂ R3 there is a heater with controlled temperature. It is required to find such a mode of its operation that the average temperature in some subregion D of Ω reaches some given value. In this paper, we consider a similar boundary control problem associated with a pseudo-parabolic equation on a segment. On the part of the border of the considered segment, the value of the solution with control parameter is given. Restrictions on the control are given in such a way that the average value of the solution in some part of the considered segment gets a given value. The auxiliary problem is solved by the method of separation of variables, while the problem in consideration is reduced to the Volterra integral equation of the second kind. By Laplace transform method, the existence and uniqueness theorems for admissible control are proved.
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An optimal boundary control problem in reaction – convection – diffusion model is considered. Solvability conditions and optimal conditions for this problem are presented. Optimal conditions and corresponding dual problem … An optimal boundary control problem in reaction – convection – diffusion model is considered. Solvability conditions and optimal conditions for this problem are presented. Optimal conditions and corresponding dual problem determining the gradient of functional are presented for the problem with quadratic quality functional. The gradient projection method for the optimal control solving is described. Computational modeling results are presented.
An algorithm for the numerical solution of the optimal speed problem with phase constraint for a parabolic equation describing the heat conduction processes in inhomogeneous media is proposed. To solve … An algorithm for the numerical solution of the optimal speed problem with phase constraint for a parabolic equation describing the heat conduction processes in inhomogeneous media is proposed. To solve the problems with the use of first-order optimization methods and finite differences on non-uniform grids, analytical formulas are obtained for the components of the gradient of the functional with respect to controllable functions. A method is proposed for selecting initial approximations for optimal controls and a step in time at each iteration, which makes it possible to accelerate the computation process. To achieve the specified accuracy, the speed problem requires 6 iterations and . Based on the analysis of the results of numerical experiments, the influence of various parameters on the iterative process is investigated and recommendations are developed on the use of the proposed algorithm. In optimal control problems, the total number of iterations in option a by the conditional gradient method is 110 and the gradient projection method is 108. In option b, the total number of iterations is CGM – 81, GPM – 64, i. e., the total number of iterations in the optimal control problem in method b the choice of the initial approximation is much less than in variant a. The optimal speed control, obtained by both methods, is close enough to test controls. Numerical experiments are also carried out in the case when the control-optimal controls have two switching points. However, the nature of the results obtained does not change. The proposed algorithm can be used to determine the optimal regime and time of thermal conductivity processes in inhomogeneous media.
Interdisciplinary research like constrained optimization of partial differential equations (PDE) for trajectory planning or feedback algorithms is an important topic. Recent technologies in high performance computing and progressing research in … Interdisciplinary research like constrained optimization of partial differential equations (PDE) for trajectory planning or feedback algorithms is an important topic. Recent technologies in high performance computing and progressing research in modeling techniques have enabled the feasibility to investigate multiphysics systems in the context of optimization problems. In this thesis a conductive heat transfer example is developed and techniques from PDE constrained optimization are used to solve trajectory planning problems. In addition, a laboratory experiment is designed to test the algorithms on a real world application. Moreover, an extensive investigation on coupling techniques for equations arising in convective heat transfer is given to provide a basis for optimal control problems regarding heating ventilation and air conditioning systems. Furthermore a novel approach using a flatness-based method for optimal control is derived. This concept allows input and state constraints in trajectory planning problems for partial differential equations combined with an efficient computation. The stated method is also extended to a Model Predictive Control closed-loop formulation. For illustration purposes, all stated problems include numerical examples.
Работа связана с изучением нелинейных параболических систем, возникающих при моделировании и управлении физико-химическими процессами, в которых происходят изменения внутренних свойств материалов. Исследовано оптимальное управление одной из таких систем, которая включает … Работа связана с изучением нелинейных параболических систем, возникающих при моделировании и управлении физико-химическими процессами, в которых происходят изменения внутренних свойств материалов. Исследовано оптимальное управление одной из таких систем, которая включает в себя краевую задачу третьего рода для квазилинейного параболического уравнения с неизвестным коэффициентом при производной по времени, а также уравнение изменения по времени этого коэффициента. Обоснована постановка оптимальной задачи с финальным наблюдением искомого коэффициента, в которой управлением является граничный режим на одной из границ области. Получено явное представление дифференциала минимизируемого функционала через решение сопряженной задачи. Доказаны условия ее однозначной разрешимости в классе гладких функций. Полученные результаты имеют практическое значение для приложений в различных технических областях, медицине, геологии и т.п. Приведены некоторые примеры таких приложений. The work is connected with investigation of nonlinear parabolic systems arising in the mathematical modeling and control of physical-chemical processes in which inner properties of materials are subjected to changes. We consider optimal control in one of such systems that involves a boundary value problem of the third kind for a quasilinear parabolic equation with an unknown coefficient at the time derivative and, moreover, an additional equation for a time dependence of this coefficient. The optimal problem with a boundary control regime is justified for the given final observation of the sought coefficient. The exact representation for the differential of the minimization functional in terms of the solutions of the conjugate problem is obtained. The form of this conjugate problem and conditions of unique solvability in a class of smooth functions are shown. The obtained results are important for applications in various technical fields, medicine, geology, etc. Some examples of such applications are discussed.
In this work the stability properties of a partial differential equation (PDE) with statedependent parameters and asymmetric boundary conditions are investigated. The PDE describes the temperature distribution inside foodstuff, but … In this work the stability properties of a partial differential equation (PDE) with statedependent parameters and asymmetric boundary conditions are investigated. The PDE describes the temperature distribution inside foodstuff, but can also hold for other applications and phenomena. We show that the PDE converges to a stationary solution given by (fixed) boundary conditions which explicitly diverge from each other. Numerical simulations illustrate the results.
This concise and highly usable textbook presents an introduction to backstepping, an elegant new approach to boundary control of partial differential equations (PDEs). Backstepping provides mathematical tools for converting complex … This concise and highly usable textbook presents an introduction to backstepping, an elegant new approach to boundary control of partial differential equations (PDEs). Backstepping provides mathematical tools for converting complex and unstable PDE into elementary, stable, and physically intuitive target PDE systems that are familiar to engineers and physicists. The text s broad coverage includes parabolic PDEs; hyperbolic PDEs of first and second order; fluid, thermal, and structural systems; delay systems; PDEs with third and fourth derivatives in space; real-valued as well as complex-valued PDEs; stabilization as well as motion planning and trajectory tracking for PDEs; and elements of adaptive control for PDEs and control of nonlinear PDEs. It is appropriate for courses in control theory and includes homework exercises and a solutions manual that is available from the authors upon request. Audience: This book is intended for both beginning and advanced graduate students in a one-quarter or one-semester course on backstepping techniques for boundary control of PDEs. It is also accessible to engineers with no prior training in PDEs. Contents: List of Figures; List of Tables; Preface; Introduction; Lyapunov Stability; Exact Solutions to PDEs; Parabolic PDEs: Reaction-Advection-Diffusion and Other Equations; Observer Design; Complex-Valued PDEs: Schrodinger and Ginzburg Landau Equations; Hyperbolic PDEs: Wave Equations; Beam Equations; First-Order Hyperbolic PDEs and Delay Equations; Kuramoto Sivashinsky, Korteweg de Vries, and Other Exotic Equations; Navier Stokes Equations; Motion Planning for PDEs; Adaptive Control for PDEs; Towards Nonlinear PDEs; Appendix: Bessel Functions; Bibliography; Index