Xinghu Wang

Consensus control of nonlinear leader–follower multi-agent systems with actuating disturbances

Abstract This paper studies a semi-global asymptotic consensus problem of nonlinear multi-agent systems with local actuating disturbances. For a modest nonlinear scenario, a consensus protocol is proposed based on a viable two-layer network. The consensus problem is treated as distributed output regulation, which is resolved by a joint decomposition of the zero-error constraint inputs and a configuration of a flexible internal model network. An illustrative example is also given to show the efficiency of the two-layer networked design.

Distributed Output Regulation of Nonlinear Multi-Agent Systems via Host Internal Model

This note presents a host internal model (h-IM) approach to distributed output regulation of reaching nonlinear leader-following consensus. Focusing on a basic nonlinear scenario of identical (or homogeneous) agents of a normal form, it is shown that the problem is solvable as long as its interaction digraph contains a certain directed spanning tree. A constructive Lyapunov protocol is proposed by incorporating a single h-IM. The result is also demonstrated by FitzHugh-Nagumo (FHN) and Lorenz type nonlinear dynamic networks.

Distributed Optimization for a Class of Nonlinear Multiagent Systems With Disturbance Rejection

The paper studies the distributed optimization problem for a class of nonlinear multiagent systems in the presence of external disturbances. To solve the problem, we need to achieve the optimal multiagent consensus based on local cost function information and neighboring information and meanwhile to reject local disturbance signals modeled by an exogenous system. With convex analysis and the internal model approach, we propose a distributed optimization controller for heterogeneous and nonlinear agents in the form of continuous-time minimum-phase systems with unity relative degree. We prove that the proposed design can solve the exact optimization problem with rejecting disturbances.

Adaptive multi-agent containment control with multiple parametric uncertain leaders

In this paper, an adaptive containment control is considered for a class of multi-agent systems with multiple leaders containing parametric uncertainties. The agents are heterogeneous though their dynamics have the same relative degree and are minimum phase, while the interconnection topology is described by a general directed graph. A distributed containment control is proposed for the agents to enter the moving convex set spanned by the leaders, based on an adaptive internal model and a recursive stabilization control law.

Leader-following consensus for an integrator-type nonlinear multi-agent systems using distributed adaptive protocol

This paper deals with the leader-following consensus problem for a class of multi-agent systems with nonlinear dynamics and directed communication topology. Two distributed adaptive nonlinear control laws are proposed based on the relative state information between neighboring agents, which solve the leader-following consensus problem and the inverse optimal adaptive leader-following consensus problem, respectively. Compared with the existing results in the literature, we do not put any restrictions on nonlinear functions and the adaptive consensus protocols are in a fully distributed fashion. A numerical example is given to verify the theoretical analysis.

Output regulation of nonlinear output feedback systems with exponential parameter convergence

Abstract This paper revisits the global robust output regulation (GROR) problem of nonlinear output feedback systems with uncertain exosystems by error output feedback control. The problem was conventionally tackled by employing a linear canonical internal model and as a result, suitable adaptive stabilization has to be done for the augmented system to achieve output regulation. Distinguished from that, a novel nonlinear internal model approach is developed in the present study that successfully converts the GROR problem into a robust non-adaptive stabilization problem for the augmented system. The feature of the new approach is two-fold. On one hand, stabilization of augmented system is disentangled from any extra adaptive control law and thus the procedure is simplified. On the other hand, it leads to explicit strict Lyapunov characterization for the closed-loop system and consequently assures exponential parameter convergence.

Leader-following consensus for a class of second-order nonlinear multi-agent systems☆

Abstract This paper deals with the leader-following consensus problem for a class of multi-agent systems with nonlinear dynamics and directed communication topology. The control input of the leader agent is assumed to be unknown to all follower agents. A distributed adaptive nonlinear control law is constructed using the relative state information between neighboring agents, which achieves leader-following consensus for any directed communication graph that contains a spanning tree with the root node being the leader agent. Compared with previous results, the nonlinear functions are not required to satisfy the globally Lipschitz or Lipschitz-like condition and the adaptive consensus protocol is in a distributed fashion. A numerical example is given to verify our proposed protocol.

Robust almost output consensus in networks of nonlinear agents with external disturbances

This paper considers robust almost output consensus control for heterogeneous and disturbed multi-agent nonlinear systems by distributed output feedback control. Taking the effect of inherent unmodeled disturbances into account, we develop a reduced order observer based consensus protocol with a performance constraint. Our study not only encompasses internal asymptotic output consensus, but also assures certain disturbance attenuation to the closed-loop system. Substantial difficulties due to nonidentical relative degrees and directed interaction graphs are surmounted in this result. Moreover, we show that in the linear case, it comes up with a novel H ∞ almost output consensus design that improves some results recently developed in the literature.

Global robust distributed output consensus of multi-agent nonlinear systems: An internal model approach

Abstract This paper studies the problem of global robust distributed output consensus of heterogeneous leader–follower multi-agent nonlinear systems by general directed output interactions. For a class of minimum-phase single-input single-output nonlinear agents having unity relative degree, it is shown that the problem is solvable by an internal model approach under certain mild conditions. A Lyapunov function based output-feedback control law is developed by converting the global output consensus into a global distributed stabilization problem for an augmented network.

A continuous leader-following consensus control strategy for a class of uncertain multi-agent systems

In this paper, we study the robust leader-following consensus problem for a class of multi-agent systems with unknown nonlinear dynamics and unknown but bounded disturbances. The control input of the leader agent is nonzero and not available to any follower agent. We first consider a class of high order chain integrator-type multi-agent systems. By employing the robust integral of the sign of the error technique, a continuous distributed control law is constructed using local information obtained from neighboring agents. Using Lyapunov analysis theory, we show that under a connected undirected information communication topology, the proposed protocol achieves semiglobal leader-following consensus. We then extend the approach to a class of more general uncertain multiagent systems. A numerical example is given to verify our proposed protocol.