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The problem of observer-based decentralized event-triggered H ∞ control for networked systems is investigated in this paper. The system measurements and control inputs are grouped into several nodes. An event-triggered transmission scheme is introduced to choose those necessary signals to be transmitted from the plant to the observer and from the controller to the actuator, where signals from control input nodes and from measurement nodes are released not necessarily synchronously. Under the decentralized event-triggered transmission scheme, H ∞ performance analysis for the resultant closed-loop system is made, and an algorithm to designing suitable observers and controllers is presented as well. Moreover, a sufficient condition is derived such that the inter-event time is strictly greater than zero. Finally, two examples are given to show the effectiveness of the method proposed in this paper. [ABSTRACT FROM AUTHOR]

In this paper we derive a sufficient condition for which unstructured decentralised fixed modes (UDFMs) of a LTI system cannot be stabilised by any form of decentralised output feedback controllers. The sufficient condition establishes the link between special UDFMs (SUDFMs) and quotient fixed modes (QFMs). The link between UDFMs and QFMs provides an unequivocal answer, which has up until now eluded researchers, as to why some UDFMs cannot be eliminated by sampled-data controllers. In addition, we use this link to highlight the role system parameter uncertainties can play in shifting stabilisable DFMs to UDMFs or QFMs and vice versa. Numerical examples are presented to illustrate all aspects of the paper. [ABSTRACT FROM AUTHOR]

In this paper, a decentralized adaptive backstepping control scheme is proposed for a class of interconnected nonlinear systems with unknown actuator failures. By introducing a smooth function, some integrable auxiliary signals and a bound estimation approach, the effect of actuator failures is successfully compensated for. The proposed scheme has the following features: (1) the total number of failures is allowed to be infinite; (2) global stability of the overall closed-loop system is achieved without any bound knowledge of uncertainties; (3) all system outputs converge to zero asymptotically regardless of the possibly infinite number of failures and the unknown interactions among subsystems. Simulation results on coupled inverted double pendulums are presented to illustrate the effectiveness of the proposed scheme. [ABSTRACT FROM AUTHOR]

This paper is concerned with the centralized and decentralized adaptive output feedback control problem for a class of uncertain interconnected nonlinear systems with unmodeled dynamics and unmeasured states. The known requirement of the upper bounds of dynamic disturbances and coupling terms in the considered system is avoided. Decentralized observers are constructed based on the K-filters to estimate the unmeasured states of each subsystem. In the design of adaptive output feedback dynamic surface control, the unknown nonlinear functions are directly approximated by neural networks, while the coupling terms being lumped together with those unknown continuous functions produced in deduction are approximated as a whole. Using the defined compact set in the stability analysis, some unknown nonlinear continuous functions are dealt with effectively. It is proved that all the signals in the closed-loop system are semi-globally uniformly ultimately bounded. Simulation results are provided to illustrate the effectiveness of the proposed approach. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, an output feedback stabilisation problem is considered for a class of large scale interconnected time delay systems with uncertainties. The uncertainties appear in both isolated subsystems and interconnections. The bounds on the uncertainties are nonlinear and time delayed. It is not required that either the known interconnections or the uncertain interconnections are matched. Then, a decentralised delay-dependant static output feedback variable structure control is synthesised to stabilise the system globally uniformly asymptotically using the Lyapunov Razumikhin approach. A case study relating to a river pollution control problem is presented to illustrate the proposed approach. [Copyright &y& Elsevier]