Class Of Large-scale Systems Research Articles

An Adaptive Controller of Large-Scale Systems

Abstract In this paper, a two —level hierarchical parameter estimator of a class of large scale systems is given based on decomposition and coordination theory. By large scale systems here we mean those systems which can’ t be represented by low order models. In the estimator, the problem of estimating parameter vector θ(k) is divided into some subproblems of estimating lower order parameter vector θ(k) in parallel. Since the algorithm of it is simple and the computational speed is fast, it is suitable for on-line parameter estimation of the large scale systems. Then a kind of adaptive controller scheme is presented. It consists of the two—level hierarchical estimator and a pole assignment controller in the certainty equivelence principle. It is suitable for the large scale systems. Finally, two simulation examples are given to illustrate the effectiveness of this adaptive controller. The simulation results are satisfactory. The two— level hierarchical estimator and adaptive controller can also be applicable to some interactive multi —input multi —output large scale systems indirectly if it is decomposed into a set of generalized single —input single —output subsystems by pre —estimating all of the interactions in the systems.

Decentralized robust control for a class of large-scale interconnected systems with uncertainties

The design problem of decentralized robust controllers is considered for a class of large-scale systems. The system considered in this paper is composed of interconnected subsystems with time-varying uncertainties. For such large-scale uncertain systems, we give a simple und new method whereby we can derive the sufficient conditions for asymptotically stabilizing the overall system using decentralized feedback robust controllers. An illustrative example is given to demonstrate the design procedure of the decentralized feedback robust controllers, in the light of the method developed in this paper.

Decentralized Control: A Simple Implementation

This paper gives a new methodology to drive a class of Large Scale Systems (the interconnected systems) in a decentralized way. The tracking problem is taking into consideration. A hierarchical structure of control is obtained : a local level ensures the stability of the global system in the Lyapunov sens, a coordinated level which is used temporarily checks the optimality. The robustness of this control law is discussed. An analysis of the autonomy degree of each sub-system is proposed.

Implicit self-tuning control for a class of large-scale systems

Abstract The problem of implicit self-tuning control is discussed for a class of large-scale systems decomposed into interconnected subsystems. We consider the case of plants that are described by a linear invariant or slowly varying model with unknown parameters.

Some Problems and Approaches of Identification in Large Scale Systems

In the paper two different identification situations being of practical interest are described first. Then some open problems related to it are summarized. Subsequently for hierarchically structured systems consisting of linear subsystems an approach is given for the determination of identifiability conditions guaranteeing a successful identification of the subsystems and the disturbances. These conditions are only based on the signal vectors which must be measured and on the a priori information given. They allow an optimal experiment design. As a further consequence of the identifiability results favourable identification strategies can be derived. Finally this is shown for a special class of large scale systems

Order Reduction of Singularly Perturbed Systems via Component Connection Models

This paper is concerned with the application of the Component Connection Model (CCM) to the reduction of a class of large Scale Systems, namely singularly perturbed systems.In this application, the reduction occurs on the component level which is assumed to be described by a set of singularly perturbed equations. Then the reduced composite system is formed using the assembly of the reduced order component models, respecting certain dynamical conditions.A relation between the Component Connection Model technique and singular perturbation techniques is established .To illustrate the utility of such a method we consider the application of the CCM to obtain a reduced order model of a ship boiler of 14th order.

Decomposition on the Basis of Structure of Discrete Systems. Application to Hierarchical Approach of a Water Quality Control Problem

This paper deals with hierarchical algorithms for digital computer control. Its purpose is to exploit the serial parallel type of interconnection structure corresponding to a wide class of large scale systems encountered in many cases of practical interest (transportation systems, hydraulic systems, physico-chemical processes,…)Several decomposition schemes are discussed for the optimal control of discrete dynamical systems and emphasis is put on convergence analysis and numerical application. They are also compared to the moot popular class of algorithms proposed for this kind of problems by Tamura (gradient type algorithms based on duality property in convex problems). Numerical comparisons are made in the context of a constrained water quality problem in rivers. A detailed description of this problem is provided with some comments on the modelling of the process and its discretization. The control corresponds to the effluent discharge from treatment plants. The state constraints are specially distributed along the river stretch considered. This application shows the advantage of the proposed sequential schemes which lead to improvement greater than two order of magnitude in computation efficiency.

A Study on the Stability of the Linear Multivariable Control System with Delays

It is shown that the stability of a class of linear multivariable control systems with delays can be determined by checking the stabilities of single-loop systems if the systems possess a diagonal dominance property. It is further shown that the stability result leads to a method of synthesizing decentralized stabilizing servo controllers for a class of large scale systems with time-delays.

On decentrally stabilizable large-scale systems

A class of large-scale systems is defined, which can always be stabilized by local feedback. Stability of the closed-loop system is connective and can tolerate nonlinearities in the interconnections. Any prescribed degree of stability can be achieved by an appropriate choice of the feedback gains.

Theory of Slow and Multiplexing Controllability and Observability

In this paper two new types of controllability and observability of linear systems are introduced and investigated. Slow controllability of linear systems by arbitrarily slow piecewise-constant inputs and multiplexing controllability by pulsed inputs are considered. Both types of controllability and their corresponding observability types arise naturally in applications of digital electronics in control systems. Multiplexing controllability is of interest when one controller controls, in time sharing mode, a set of a large number of linear systems. This could be of importance in investigating a class of large scale systems. The developed results apply to both continuous and discrete-time systems.

Decentrally stabilizable linear and bilinear large-scale systems†

Abstract Two classes of large-scale systems are identified, which can always be stabilized by decentralized feedback control. For the class of systems composed of interconnected linear subsystems, we can choose local controllers for the subsystems to achieve stability of the overall system. The same linear feedback scheme can be used to stabilize a class of linear systems with bilinear interconnections. In this case, however, the scheme is used to establish a finite region of stability for the overall system. The stabilization algorithm is applied to the design of a control system for the Large-Space Telescope.

HORIZONTALLY STRATIFIED MEDIUM AS A REFERENCE LARGE SCALE SYSTEM*

AbstractThe geophysical system of horizontal layers may be considered as a large scale system. A large class of systems is identified which are equivalent to the geophysical processes in horizontal layering. The property of hierarchical aggregation of layers forms a convenient framework within which the peculiarities of such systems can be studied. Geophysical processes in multilayered media may serve as a reference physical model for a specified class of large scale systems, in order to take advantage and to apply geophysical methods of data processing, system analysis, and parameter identification.Specified large scale systems are decomposable, like geophysical systems, by use of recursive schemes. A category particulary susceptible to such a decomposition is any polynomial which is stable inside the unit circle. Sophisticated geophysical concepts, such as anisotropy, equivalence, and disappearance, can be used to approximate or to simplify the system by vanishing or adjusting the decomposition coefficients.

Optimizing One Class of Large-Scale Systems

The paper is concerned with optimal control problems for a complex dynamic plant consisting of a number of subsystems having the same final objective and the same constraint on control actions. Complex nonlinear relationships betweem plant coordinates and controls are assumed. A linear programming computing algorithm for approximate solution of such problems is proposed.