Application of two decomposition/coordination methods to interconnected distributed-parameter systems of parabolic type is treated. After formulation of both methods - penalization and re-injection - for the optimal c...
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Application of two decomposition/coordination methods to interconnected distributed-parameter systems of parabolic type is treated. After formulation of both methods - penalization and re-injection - for the optimal control problem, the methods are also formulated for resolution of the parameter identification problem. An emphasis lies in the treatment of parameters that occur in several subproblems simultaneously. From computational experiences it can be stated, that decomposition/coordination methods applied to parameter identification work highly satisfactory and are much less time-consuming than the treatment of the corresponding coupled equations. A simple example is given at the end of the paper.
Many distributed-parameter systems consist of interconnected subsystems involving fast and slow physical phenomena or reducing to a number of independent subsystems when a scalar parameter ε is zero. The purpose of t...
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Many distributed-parameter systems consist of interconnected subsystems involving fast and slow physical phenomena or reducing to a number of independent subsystems when a scalar parameter ε is zero. The purpose of this paper is to treat the optimal control of such systems by invoking the ε-coupling and singular perturbation approaches developed by Kokotovic and his associates for lumped-parameter large-scale systems. In the case of ε-coupled distributed-parameter systems it is shown that the optimal state feedback matrix can be approximated by a Volterra-MacLaurin series with coefficients determined by solving two lower-order decoupled Riccati and linear equations. By using an mth-order approximation of the optimal feedback matrix, one obtains a (2m+l)th order approximation of the optimal performance function. In the singular perturbation approach the result is that for an O(ε 2 ) suboptimal control one must solve two decoupled Riccati equations, one for the fast and one for the slow subsystem and then construct appropriately the composite control law. By using only the Riccati equation for the slow subsystem, one obtains an 0(ε) suboptimal control. The singular perturbation technique can also be used to treat interconnected distributed-parameter systems involving many strongly coupled slow subsystems and weakly coupled fast subsystems.
First-order necessary and sufficient conditions are obtained for the following quasilinear distributed-parameter optimal control problem:$$max\left\{ {J(u) = \int_\Omega {F(x,u,t) d\omega + } \int_{\partial \Omega } {...
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First-order necessary and sufficient conditions are obtained for the following quasilinear distributed-parameter optimal control problem:$$max\left\{ {J(u) = \int_\Omega {F(x,u,t) d\omega + } \int_{\partial \Omega } {G(x,t) \cdot d\sigma } } \right\},$$ subject to the partial differential equation$$A(t)x = f(x,u,t),$$ wheret,u,G are vectors andx,F are scalars. Use is made of then-dimensional Green's theorem and the adjoint problem of the equation. The second integral in the objective function is a generalized surface integral. Use of then-dimensional Green's theorem allows simple generalization of single-parameter methods. Sufficiency is proved under a concavity assumption for the maximized Hamiltonian$$H^\circ (x,\lambda ,t) = \max \{ H(x,u,\lambda ,t):u\varepsilon K\} $$.
This paper describes a method for the identification of the parameters entering into the equations of motion of distributed-para-meter systems. Because the motion of distributedsystems is described in terms of partia...
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This paper describes a method for the identification of the parameters entering into the equations of motion of distributed-para-meter systems. Because the motion of distributedsystems is described in terms of partial differential equations, these parameters are in general continuous functions of the spatial variables. For vibrating systems, these parameters ordinarily represent the mass, stiffness and damping distributions. In this paper, these distributions are expanded in terms of finite series of known functions of the spatial variables multiplied by undetermined coefficients. Assuming that the nature of the equations of motion is known and that a limited number of eigenvalues and eigenfunctions is given, use is made of the least-squares method, in conjunction with the eigenfunctions' orthogonality, to compute the undetermined coefficients, thus identifying the system distributedparameters.
A simple practical method for designing antenna-feed positioning control systems for large deployable spaceborne antenna systems with flexible booms is proposed. The approach is based on the mechanical decoupling of t...
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A simple practical method for designing antenna-feed positioning control systems for large deployable spaceborne antenna systems with flexible booms is proposed. The approach is based on the mechanical decoupling of the antenna-feed from the boom so that the positioning control system can be designed without taking boom dynamics into consideration, thus avoiding a complex infinite dimensional control problem. The basic idea is illustrated by a simple angular positional control system attached to a flexible boom restricted to torsional motion only. The application of this approach to more complex situations is discussed briefly.
This paper deals with the prediction problem of air pollutant concentrations over the industrial area of Tokushima Prefecture, Japan. The mathematical model used for the prediction of air pollution, which describes th...
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This paper deals with the prediction problem of air pollutant concentrations over the industrial area of Tokushima Prefecture, Japan. The mathematical model used for the prediction of air pollution, which describes the transport and diffusion of pollutants from stack emissions into the atmosphere, is expressed by the three-dimensional partial differential equation known as the advection diffusion model with initial and boundary conditions. Diffusion coefficients characterizing this model are determined effectively from the statistical processing of the available measured data obtained at two monitoring stations. The measured data of sulpher dioxide concentrations are classified by season, weather and wind speed, and then the identification of these coefficients for each class is carried out by using a line search method because of its numerical stability. The estimation theory is extensively applied to this model for obtaining the useful estimates of the spatial and temporal concentration distributions on the basis of actual measured data, in which the analytical solution of this model is given by using the Green's function under some reasonable assumptions and the suitable transformation. The effectiveness of the proposed approach for the prediction of air pollutant is indicated in simulation results.
This paper provides a dynamic programming approach to the maximum principle for the optimal control of systems with distributedparameters. The process of the systems under consideration is governed by a partial diffe...
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This paper provides a dynamic programming approach to the maximum principle for the optimal control of systems with distributedparameters. The process of the systems under consideration is governed by a partial differential equation.
Recently, differential games have received considerable attention and find applications in both antagonistic and cooperative situations. However the theory has mainly been restricted to lumped-parameter differential o...
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Recently, differential games have received considerable attention and find applications in both antagonistic and cooperative situations. However the theory has mainly been restricted to lumped-parameter differential or difference games. The purpose of the present paper is to treat difference distributed-parameter (DP) games, i.e. distributed-parameter differential games formulated in discrete time. The Nash strategy is first used, and the open-loop, closed-loop, and open/closed-loop solutions are deri-ved. Then, the more general case of periodic state measurements is considered and the periodic open-loop and periodic open/closed-loop policies are determined. In all cases the solution is found in the form of recursive algorithms based on a series of discrete-time DP equations. Finally, the non-inferior and minimax strategies are employed, and the derivation of the corresponding solutions is outlined. The paper includes an illustrative worst-case-design distributed-parameter nuclear-reactor example.
Since mechanically flexible systems are distributed-parameter systems, they are infinite-dimensional in theory and, in practice, must be modelled by large-dimensional systems. The fundamental problem of actively contr...
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Since mechanically flexible systems are distributed-parameter systems, they are infinite-dimensional in theory and, in practice, must be modelled by large-dimensional systems. The fundamental problem of actively controlling very flexible systems is to control a large-dimensional system with a much smaller dimensional controller. For example, a large number of elastic modes may be needed to describe the behavior of a flexible satellite; however, active control of all these modes would be out of the question due to onboard computer limitations and modelling error. Consequently, active control must be restricted to a few critical modes. The effect of the residual (uncontrolled) modes on the closed-loop system is often *** this paper, we consider the class of flexible systems that can be described by a generalized wave equation,utt+Au=F, which relates the displacementu(x,t) of a body Θ inn-dimensional space to the applied force distributionF(x,t). The operatorA is a time-invariant symmetric differential operator with a discrete, semibounded spectrum. This class of distributedparametersystems includes vibrating strings, membranes, thin beams, and thin *** control force distribution$$F(x,t) = \sum\limits_{i = 1}^M { \delta (x - x_i )f_i (t)} $$ is provided byM point force actuators located at pointsxi on the body. The displacements (or their velocities) are measured byP point sensorsyi(t)=u(zj,t), orut(zj,t),j=1, 2, ...,P, located at various pointszj along the *** obtain feedback control ofN modes of the flexible system and display the controllability and observability conditions required for successful operation. We examine the control and observation spillover due to the residual modes and show that the combined effect of spillover can lead to instabilities in the closed-loop system. We suggest some remedies for spillover, including a straightforward phase-locked loop prefilter, to remove the instability *** illustrate the concepts of this p
Extremum principles intended for use in optimal control are derived in the form of necessary conditions and sufficient conditions, formulated in general normed linear spaces. The method of application is illustrated b...
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Extremum principles intended for use in optimal control are derived in the form of necessary conditions and sufficient conditions, formulated in general normed linear spaces. The method of application is illustrated by several examples involving optimal control problems, mathematical programming problems, lumped-parametersystems, and distributed-parameter systems. The basic theorems provide a unified approach which is applicable to a wide variety of problems in open-loop optimal control.
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