This article proposes an event-triggered control design for cooperative control of heterogeneous multiagent systems. The design is serial in nature and consists of the design of a distributed event-triggered observer for each follower agent that estimates the desired information of the leader system in the presence of parametric uncertainty and, based on this observer, the design of a distributed event-triggered controller. A salient feature of our observer design is that it obeys the separation principle in the sense that the event-triggered control can be designed after the observer has been designed. As a result, the observer is applicable to different follower agent dynamics and the event-triggered time sequence for the controller is asynchronous of that of the observer. We implement this design scheme on linear heterogeneous multiagent systems and uncertain Euler–Lagrange multiagent systems, and achieve results that significantly extend the existing ones.

The cooperative robust output regulation problem for a class of second-order nonlinear multi-agent systems with an exactly known exosystem has been studied recently. This paper further studies the same problem for the same class of systems subject to an uncertain exosystem. We first show that the problem can be converted into the adaptive stabilization problem for an augmented system composed of the given multi-agent system and the distributed internal model. Due to the uncertain parameters in the exosystem, the augmented system is a nonlinear multi-input, multi-output system with both linearly parameterized uncertainties and norm bounded nonlinear uncertainty. By combining the adaptive control technique and the robust control technique, we will solve our problem by a distributed adaptive robust state feedback controller.

This paper further improves the results for the leader-following rendezvous problem for multiple uncertain Euler-Lagrange systems. Based on a self-tuning adaptive observer, which can work under the more relaxed assumption that the information of the leader system is only available to informed followers in the rendezvous network, a full state distributed control law, depending only on the neighbor's information, is first proposed to preserve the connectivity of the initially connected rendezvous network, as well as to achieve the asymptotic tracking of leader's signal. And then such full state control strategy is further improved to be independent of the relative velocity of two neighboring agents by introducing an additional time-varying nonlinear term, determined by potential function. At the same time, dynamic gains are also introduced to make control parameter independent of system dynamics.

The consensus problem for multiple Euler–Lagrange systems has been extensively studied under various assumptions on the connectivity of the communication graph. In practice, it is desirable to enable the control law the capability of maintaining the connectivity of the communication graph, thus achieving consensus without assuming the connectivity of the communication graph. We call such a problem as consensus with connectivity preservation. In this paper, we will study this problem for multiple uncertain Euler–Lagrange systems. By combining the adaptive control technique and potential function technique, we will show that such a problem is solvable under a set of standard assumptions. By employing different potential functions, our approach will also lead to the solution of such problems as rendezvous and flocking.

This article studies fixed-time robust networked observers to estimate the information of a leader system containing unknown parameters. The construction of observers combines the internal model principle and the fixed-time control technique in a network with a directed topology. The observers are further applied to the fixed-time attitude synchronization problem for multiple spacecraft systems whose attitudes are represented by unit quaternion. Both rigorous analysis and numerical simulation demonstrate that the fixed-time synchronization of attitude and angular velocity between multiple spacecrafts and a specified leader system is achieved by the observer-based control design.