Strong Structural Controllability of Systems on Colored Graphs

This paper deals with structural controllability of leader-follower networks. The system matrix defining the network dynamics is a pattern matrix in which a priori given entries are equal to zero, while the remaining entries take nonzero values. The network is called strongly structurally controllable if for all choices of real values for the nonzero entries in the pattern matrix, the system is controllable in the classical sense. In this paper we introduce a more general notion of strong structural controllability which deals with the situation that given nonzero entries in the system's pattern matrix are constrained to take identical nonzero values. The constraint of identical nonzero entries can be caused by symmetry considerations or physical constraints on the network. The aim of this paper is to establish graph theoretic conditions for this more general property of strong structural controllability.Comment: 13 page

Leader-based Multi-Agent Systems

In this thesis, we analyze multi-agent systems under the leader/follower control scheme. We take a graph-theoretic approach to defining the system which allows us to create a state-space representation of the agents. Using this model we can consider the group of agents as a linear time-invariant system under point mass dynamics. Linear control theory is used to examine the controllability of these systems. Uncontrollability from graph topology and symmetry is also explored. The process of electing both an optimal leader and set of optimal leaders to bring the agents to a consensus is investigated. Conditions of optimality require the leaders to minimize a cost function while simultaneously leading to a controllable network. At the end, we decompose the cost index in such a way as to show its relation to the underlying commutation graph of the network and the desired location of the agents. Finally, we demonstrate how varying the weights and the leader configuration affects the performance of the network

Distributed Cooperative Regulation for Multiagent Systems and Its Applications to Power Systems: A Survey

Cooperative regulation of multiagent systems has become an active research area in the past decade. This paper reviews some recent progress in distributed coordination control for leader-following multiagent systems and its applications in power system and mainly focuses on the cooperative tracking control in terms of consensus tracking control and containment tracking control. Next, methods on how to rank the network nodes are summarized for undirected/directed network, based on which one can determine which follower should be connected to leaders such that partial followers can perceive leaders’ information. Furthermore, we present a survey of the most relevant scientific studies investigating the regulation and optimization problems in power systems based on distributed strategies. Finally, some potential applications in the frequency tracking regulation of smart grids are discussed at the end of the paper