ABSTRACT
This paper deals with the predefined-time synchronization for a class of nonlinear multi-agent systems. The notion of passivity is exploited to design the controller for predefined-time synchronization of a nonlinear multi-agent system, where the time of synchronization can be preassigned. Developed control can be used to synchronize large-scale, higher-order multi-agent systems as passivity is an important property in designing control for complex control systems, where the control inputs and outputs are considered in determining the stability of the system in contrast to other approaches, such as state-based Control We introduced the notion of predefined-time passivity and as an application of the exposed stability analysis, static and adaptive predefined-time control algorithms are designed to study the average consensus problem for nonlinear leaderless multiagent systems in predefined-time. We provide a detailed mathematical analysis of the proposed protocol, including convergence proof and stability analysis. We discussed the tracking problem for a single agent, and designed state feedback and adaptive state feedback control scheme to make tracking error predefined-time passive and then showed that in the absence of external input, tracking error reduces to zero in predefined-time. Furthermore, we extended this concept for a nonlinear multi-agent system and designed state feedback and adaptive state feedback control scheme which ensure synchronization of all the agents in predefined-time. To further strengthen the idea, we applied our control scheme to a nonlinear multi-agent system by taking the example of Chua's circuit. Finally, we compared the result of our developed predefined-time synchronization framework with finite-time synchronization scheme available in literature for the Kuramoto model.
ABSTRACT
The issue of secure estimation for cyber-physical systems subject to unknown inputs and stealthy deception attacks is addressed in this paper. First, the unknown inputs are treated as augmented state and on the basis of that, the original plant is transformed into a singular system, which is decoupled with the unknown inputs. Then, for the purpose of reducing communication burden and avoiding congestion in the network, the event-triggered mechanism is introduced. Two approaches are presented to accomplish state estimation. The former one is known as the monotone system method. In the latter method, an input-to-state stable robust observer is constructed and by using the set-membership method, approximated estimation error is obtained. Finally, the effectiveness of the proposed method is verified by two illustrative examples.