Meilin Li

This article proposes the dynamic event-triggered and self-triggered protocols to achieve the prescribed-time consensus of a class of nonlinear multi-agent systems with a trade-off performance. Firstly, a dynamic event-triggered control protocol and a time-varying parameter are jointly designed to accomplish the prescribed-time consensus. Secondly, a dynamic self-triggered control protocol is further designed to avoid continuous monitoring of the system states. The designed control protocols both can ensure the avoidance of the Zeno phenomenon and allow for dynamic adjustment between the specified time and the inter-event time. Specially, the minimum inter-event time can be designed as an arbitrarily large bounded constant when every agent is an integrator system. Finally, an example system is utilized to demonstrate the effectiveness of the designed algorithms.

The leader-following consensus problem for input constrained multiagent systems is investigated in this article. First, the follower agents are divided into several clusters based on the connectivity of the communication topology. Then, a novel clustered time-varying dynamic event-triggered mechanism (ETM) with adjustable minimum interevent time (MIET) is designed for each cluster, such that the follower agents within the same cluster share a unique ETM and are not influenced by agents in other clusters. Next, an event-triggered-based bounded control protocol with a time-varying gain and a parameter scheduler is proposed for each follower. Finally, the leader-following consensus can be realized with a faster convergence rate and the frequency of controller updates can be significantly reduced. Obviously, with the proposed clustered time-varying dynamic ETM, the Zeno-free phenomenon is guaranteed and the MIET can be modified by adjusting only a design parameter. Simulation results validate the effectiveness of the designed control algorithm.

The article proposes a dynamic time-varying event-triggered strategy to achieve semi-global finite-time rendezvous control of saturated spacecraft. The main idea of the designed dynamic event-triggered strategy is to construct the controller that contains the time-varying high-gain and a dynamic event-triggered mechanism simultaneously. Moreover, a positive lower bound of inter-event times is obtained by using the properties of the parametric Lyapunov equation, such that the Zeno phenomenon is eliminated. Finally, the designed dynamic time-varying event- triggered strategy is verified by simulation results.

This paper solves the problem of spacecraft rendezvous with input delay by designing the periodic event-triggered control (PETC) and periodic self-triggered control (PSTC), respectively. Firstly, a PETC based on the discrete-time parametric Lyapunov equation (DPLE) is designed to stabilize the delayed spacecraft rendezvous systems. Moreover, in order to avoid monitoring the measurement errors, a PSTC algorithm that the updates of the next control law depend on the previous triggered states is also designed. Specially, by using the properties of the DPLE, this new approach is not only simple, but also provides an easy and explicit condition on the only parameter of DPLE to guarantee the non-triviality of the designed PETC and PSTC. Finally, the effectiveness of theoretical results is verified by simulations. Note to Practitioners —Although this paper was inspired by the problem of spacecraft rendezvous, the designed algorithms can also be applied to other time-delay systems. Existing general event-triggered control methods have been used to solve the problem of spacecraft rendezvous for reducing the communication load, although this often complicates the design of the controller due to preventing the occurrence of Zeno phenomenon. To overcome this drawback, This paper proposes a periodic event-triggered control to achieve the spacecraft rendezvous with input delay, which naturally avoids the occurrence of Zeno phenomenon. In addition, a periodic self-triggered control is also designed, which has never been designed to solve the problem of delayed spacecraft rendezvous.

The dynamic positioning of marine intelligent vehicles is gradually becoming the core technique to perform herculean tasks in complex sea conditions. To cope with the composite ocean disturbances and the constraint of communication resources, this paper proposes an event-triggered anti-disturbance dynamic positioning control strategy with performance optimization via reinforcement learning. Firstly, to overcome the composite disturbances caused by external environmental disturbance and internal uncertainties, the disturbance estimator with a fuzzy logic system is established. By constructing an event-triggered mechanism that relies on position and heading information, an event-triggered optimized dynamic positioning controller is designed by combining modified backstepping and reinforcement learning methods. The designed controller consists of a composite anti-disturbance controller and an optimized compensator. Thus, unnecessary communication can be avoided and the performance index is minimized simultaneously. Furthermore, the errors of the closed-loop system are rigorously proved to be bounded. At last, the validity of the proposed control scheme for a marine intelligent vehicle is illustrated by simulation and comparison studies.

This paper investigates the consensus control of multi-agent systems (MASs) with constrained input using the dynamic event-triggered mechanism (ETM). Consider the MASs with small-scale networks where a centralized dynamic ETM with global information of the MASs is first designed. Then, a distributed dynamic ETM which only uses local information is developed for the MASs with large-scale networks. It is shown that the semi-global consensus of the MASs can be achieved by the designed bounded control protocol where the Zeno phenomenon is eliminated by a designable minimum inter-event time. In addition, it is easier to find a trade-off between the convergence rate and the minimum inter-event time by an adjustable parameter. Furthermore, the results are extended to regional consensus of the MASs with the bounded control protocol. Numerical simulations show the effectiveness of the proposed approach.