Chu Tianguang

Swarm Dynamics of a Group of Mobile Autonomous Agents

We propose a simple swarm model to study collective behaviour of a group of mobile autonomous agents interacting through a long range attraction and short range repulsion function. It is shown that the individuals (agents) will aggregate and eventually form a cohesive cluster of finite size around the swarm centre in a finite time, and the size depends only on the parameters of the swarm model. Furthermore, it is also shown that all the individuals will converge to equilibrium positions of the swarm model, and thus the configuration of the swarm converges to a constant constellation. Numerical simulations are also worked out to illustrate the analytical results.

Aggregation and Pattern Formation of Multi-Agent Systems

This paper considers a type of multi-agent systems. The interactions among the individual agents are assumed to be universally repulsive and selectively attractive, so as to realize desired pattern formations in the systems by choosing appropriate coupling topologies. Specifically, it is shown that the system with symmetric couplings always displays convergent dynamics to steady-state formations. Whereas in asymmetric case the system exhibits more complex behavior, such as self-organized oscillations. It is also demonstrated numerically how to arrived at typical formations in a multi-agent system by assigning specific form of attractive coupling structures.

Collective Behaviors and Self-organizing Cooperation

We investigate evolutionary games on complex networks. First, we investigate the evolutionary prisoners dilemma game on scale-free networks with community structures. Then we explore the heterogeneitys role in the evolution of cooperation on a variant of Newman-Watts small-world networks. We also study the influence of different initial conditions on the evolution of cooperation corresponding to different initial configurations for cooperators and defectors distributing among the vertices of networks. Moreover, we investigate Snowdrift game on an empirical social network. Furthermore, we study the entangled dynamics of the evolution of network structure and strategy. Finally, we present the unresolved open problems, future research directions, and possible application areas of evolutionary games on complex networks.

Swarm Dynamics and Coordinated Control

Swarming behavior is ubiquitous in nature and society. It is of both theoretical and practical importance to investigate the underlying principles and mechanism of coordination and cooperation emerging in swarms. This paper discusses the basic issues in this direction in the field of systems and control. We review some swam models commonly studied in the literature, analyze the roles and effects of connection topology on swarm dynamics, as well as the effects of variable topologies, communication delays, and exogenous influences etc. We also give some numerical simulation results to demonstrate complex aggregation-oscillation behavior of swarms in the cases of asymmetric coupling and delayed communication.

TECHNICAL STABILITY OF NONLINEAR TIME-VARYING SYSTEMS WITH SMALL PARAMETERS *

Technical stability allowing quantitative estimation of trajectory behavior of a dynamical system over a given time interval was considered. Based on a differential comparison principle and a basic monotonicity condition, technical stability relative to certain prescribed state constraint sets of a class of nonlinear time-varying systems with small parameters was analyzed by means of vector Liapunov function method. Explicit criteria of technical stability are established in terms of coefficients of the system under consideration. Conditions under which the technical stability of the system can be derived from its reduced linear time-varying (LTV) system were further examined, as well as a condition for linearization approach to technical stability of general nonlinear systems. Also, a simple algebraic condition of exponential asymptotic stability of LTV systems is presented. Two illustrative examples are given to demonstrate the availability of the presently proposed method.