Class Of Uncertain Large-scale Systems Research Articles

Decentralized adaptive fuzzy tracking control for a class of uncertain large-scale systems with actuator nonlinearities

This paper studies the problem of decentralized adaptive tracking control for a class of nonlinear large-scale systems with unmeasurable states and actuator nonlinearities. For each subsystem, a novel decentralized disturbance rejection filter is designed to estimate both system states and external disturbances. The decentralized controller with adaptive laws is designed based on back-stepping techniques. It is proved that all the signals of the resulting closed-loop system are bounded, and the output tracking errors of subsystems converge to a desired neighborhood of origin. Simulation results illustrate the effectiveness of the method proposed in this paper.

Robust decentralized stabilization of Markovian jump large-scale systems: A neighboring mode dependent control approach

This paper is concerned with the decentralized stabilization problem for a class of uncertain large-scale systems with Markovian jump parameters. The controllers use local subsystem states and neighboring mode information to generate local control inputs. A sufficient condition involving rank constrained linear matrix inequalities is proposed for the design of such controllers. A numerical example is given to illustrate the developed theory.

Decentralized sliding mode quantized feedback control for a class of uncertain large-scale systems with dead-zone input

This paper is concerned with the robust quantized feedback stabilization problem for a class of uncertain nonlinear large-scale systems with dead-zone nonlinearity in actuator devices. It is assumed that state signals of each subsystem are quantized and the quantized state signals are transmitted over a digital channel to the controller side. Combined with a proposed discrete on-line adjustment policy of quantization parameters, a decentralized sliding mode quantized feedback control scheme is developed to tackle parameter uncertainties and dead-zone input nonlinearity simultaneously, and ensure that the system trajectory of each subsystem converges to the corresponding desired sliding manifold. Finally, an example is given to verify the validity of the theoretical result.

Adaptive sliding mode controller design for decentralised model following of large-scale systems with time-varying delay interconnections

The problem of decentralised robust model following is considered for a class of uncertain large-scale systems with time-varying delay interconnections. It is assumed that the upper bounds of uncertainties and interconnections are unknown. For such a class of uncertain large-scale interconnected time-delay systems, some adaptation laws are introduced to updating the unknown upper bounds, and a class of decentralised local adaptive robust sliding mode controllers is proposed by combining a sliding mode controller with the adaptation law. The proposed decentralised local adaptive robust controller can guarantee that the local tracking error of each subsystem decreases asymptotically to zero in the presence of uncertainties and interconnection terms with time-varying delays. Finally, a numerical example is given to demonstrate the validity of the results.

Decentralized Adaptive Robust Tracking and Model Following for Large-Scale Systems Including Delayed State Perturbations in the Interconnections

The problem of decentralized robust tracking and model following is considered for a class of uncertain large-scale systems including delayed state perturbations in the interconnections. In this paper, it is assumed that the upper bounds of the delayed state perturbations, uncertainties, and external disturbances are unknown. A modified adaptation law with σ-modification is introduced to estimate such unknown bounds, and on the basis of the updated values of these unknown bounds, a class of decentralized local memoryless state feedback controllers is constructed for robust tracking of dynamical signals. The proposed decentralized adaptive robust tracking controllers can guarantee that the tracking errors between each time-delay subsystem and the corresponding local reference model without time-delay decrease uniformly asymptotically to zero. Finally, a numerical example is given to demonstrate the validity of the results.

Robust decentralized control of large-scale systems via H ∞ theory and using descriptor system representation

In this paper, a method for design of linear decentralized robust controllers for a class of uncertain large-scale systems in general form is presented. For a given large-scale system, an equivalent descriptor system in input–output decentralized form is defined. Using this representation, closed-loop diagonal dominance sufficient conditions are derived. It is shown that by appropriately minimizing the weighted sensitivity function of each isolated subsystem, these conditions are achieved. Solving the appropriately defined H∞ local problem for each isolated uncertain subsystem, the interactions between the subsystems are reduced, and the overall stability and robust performance are achieved in spite of uncertainties. The designs are illustrated by a practical example.

A decentralized model following controllers for a class of large‐scale interconnected dynamical systems with uncertainties

AbstractThe problem of decentralized robust tracking and model following is considered for a class of large‐scale interconnected systems with uncertainties. A class of linear decentralized state feedback controllers are proposed for robust tracking of dynamical signals in such a class of uncertain large‐scale systems. The proposed decentralized tracking controllers can guarantee that the tracking errors between each subsystem and local reference model are uniformly ultimately bounded. Moreover, we modify the linear controllers by introducing some nonlinear parts so that the tracking errors decrease asymptotically to zero in the presence of uncertain parameters and interconnection terms. Finally, an illustrative example is given to demonstrate the validity of our results. © 2002 Wiley Periodicals, Inc. Electr Eng Jpn, 142(2): 48–58, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10101

Decentralized state-feedback stabilization and robust control of uncertain large-scale systems with integrally constrained interconnections

This paper is concerned with a problem of stabilization and robust control design for interconnected uncertain systems. A new class of uncertain large-scale systems is considered in which interconnections between subsystems as well as uncertainties in each subsystem are described by integral quadratic constraints. The problem is to design a set of local (decentralized) controllers which stabilize the overall system and guarantee robust disturbance attenuation in the presence of the uncertainty in interconnections between subsystems as well as in each subsystem. The paper presents necessary and sufficient conditions for the existence of such a controller. The proposed design is based on recent absolute stabilization and minimax optimal control results and employs solutions of a set of game-type Riccati algebraic equations arising in H ∞ control.

Decentralized adaptive regulation with unknown high-frequency-gain signs

We propose for the first time a decentralized adaptive control scheme without requiring a priori information on subsystem high-frequency-gain signs. This is achieved by introducing Nussbaum-type functions in local adaptive controllers, and developing a new analysis approach which is quite different from the conventional one used in centralized adaptive control involving a Nussbaum-type function. With the help of integrator backstepping, the decentralized control scheme can also be applied to high-relative-degree systems. The results of this paper enlarge the class of uncertain large-scale systems for which decentralized adaptive control can be designed.