Heterogeneous Communication Delays Research Articles

Robust Consensus Controller Design for Nonlinear Relative Degree Two Multi-Agent Systems With Communication Constraints

Robust static output-feedback controllers are designed that achieve consensus in networks of heterogeneous agents modeled as nonlinear systems of relative degree two. Both ideal communication networks and networks with communication constraints are considered, e.g., with limited communication range or heterogeneous communication delays. All design conditions that are presented are scalable to large and heterogeneous networks because the controller parameters depend only on the dynamics of the corresponding agent and its neighbors, but not on other agents in the network.

Linear matrix inequality-based novel stability criteria of the primal-dual algorithm with heterogeneous communication delays

A fundamental and required property of congestion control algorithms in computer networks is stability. In this study, a class of appropriate Lyapunov functionals is proposed to investigate asymptotic stability in the second-order congestion control systems with heterogeneous communication delays. Novel linear matrix inequality-based delay-dependent stability criteria are given by exploiting free weighting matrices, which can overcome conservativeness of most methods involving a fixed model transformation. Simulation results show that the stability criteria proposed in this study are less conservative in the sense that larger range of control gains and communication delays can be accommodated.

Large Coupled Oscillator Systems with Heterogeneous Interaction Delays

In order to discover generic effects of heterogeneous communication delays on the dynamics of large systems of coupled oscillators, this Letter studies a modification of the Kuramoto model incorporating a distribution of interaction delays. Corresponding to the case of a large number N of oscillators, we consider the continuum limit (i.e., N --> infinity). By focusing attention on the reduced dynamics on an invariant manifold of the original system, we derive governing equations for the system which we use to study the stability of the incoherent states and the dynamical transitional behavior from stable incoherent states to stable coherent states. We find that spread in the distribution function of delays can greatly alter the system dynamics.

Formation control of multi-agent systems with heterogeneous communication delays

In this article, the formation control is investigated for a network of second-order dynamic agents with heterogeneous communication delays. The desired stationary formation is achieved by introducing diverse self-delay for each agent. In addition, a delay-dependent formation control algorithm is proposed to achieve the desired moving formation. Based on the frequency-domain analysis and matrix theory, sufficient conditions are obtained for the multi-agent systems asymptotically converging to desired stationary and moving formations, respectively. Simulation results illustrate the correctness of the results.

Consensus of multi-agent moving systems with heterogeneous communication delays

A consensus of mobile multi-agent systems is a question with practical significance in the complex dynamics system. In this paper, a multi-agent moving system with the heterogeneous communication delays is studied under the hypothesis of fixed, undirected and connected topology. Applying the generalised Nyquist criterion, the multi-agent delayed algorithm is analysed, and many sufficient conditions are obtained to ensure the consensus of the moving systems. Finally, many computer simulations are used to show the validity of the results.

Novel delay-range-dependent stability analysis of the second-order congestion control algorithm with heterogonous communication delays

Congestion in computer networks is one of the main reasons for degraded performance and poor quality of service and a good congestion control algorithm is thus essential in computer networks. A fundamental and required property of any control system is its stability. In this paper, we investigate the problem of asymptotic stability in the second-order congestion control system with heterogeneous communication delays. A new approach to stability analysis of the second-order congestion control algorithms is proposed, where the free weighting matrix technique is used and the knowledge of the delay interval is also utilized. Several linear matrix inequality (LMI)-based delay-range-dependent stability criteria are proposed. Simulation results show that the stability criteria proposed in this paper are much less conservative than the existing ones in the sense that the larger range of communication delays can be accommodated.

Stability of the primal-dual algorithm for congestion control

This paper investigates the stability of the primal-dual algorithm for Internet congestion control in the presence of heterogeneous round-trip communication delays. Based on the geometric analysis of frequency response functions of the congestion control system, some sufficient conditions for the local asymptotic stability of the primal-dual algorithm are established. Compared to the existing references, the main contribution of this paper is that in addition to the new sufficient conditions it also obtains some scalability conditions under which the decentralized stability criteria hold for the primal-dual algorithm.

Stability of distributed congestion control with heterogeneous feedback delays

We investigate how congestion control can achieve efficient usage of network resources in the presence of heterogeneous communication delays between network users and resources. To this end, we consider a fluid flow model of network behavior. We study the stability of the system's behavior under small perturbations around the target equilibrium point (local stability). We establish several criteria for stability of certain linear delay-differential equations, via a technique which essentially reduces the question to studying stability of ordinary differential equations. These results are then used to derive sufficient conditions for local stability of the network congestion control problem. The same issue has been studied by Johari et al. (2001), where the authors propose a conjecture according to which local stability can be ensured in a distributed way. The correctness of the conjecture was established by Johari et al., only in degenerate cases where feedback delays coincide. Our results show that a modified form of the conjecture holds true for arbitrary feedback delays.

95/01858 Rotary absorption system for industrial processes

Distributed averaging-based integral (DAI) controllers are becoming increasingly popular in power system applications. The literature has thus far primarily focused on disturbance rejection, steady-state optimality and adaption to complex physical system models without considering uncertainties on the cyber and communication layer nor their effect on robustness and performance. In this paper, we derive sufficient delay-dependent conditions for robust stability of a secondary-frequency-DAI-controlled power system with respect to heterogeneous communication delays, link failures and packet losses. Our analysis takes into account both constant as well as fast-varying delays, and it is based on a common strictly decreasing Lyapunov–Krasovskii functional. The conditions illustrate an inherent trade-off between robustness and performance of DAI controllers. The effectiveness and tightness of our stability certificates are illustrated via a numerical example based on Kundur’s four-machine-two-area test system.