Optimization of communication topology for persistent formation in case of communication faults

To address the optimization problem of communication topology for persistent formation in the case of communication faults such as link interruption,transmitter failure,and receiver failure a two-stage model including fast reconstruction of communication topology and re-optimization of communication topology is constructed.Then,a fast reconstruction algorithm of communication topology for persistent formation(FRA-CT-PF),based on optimally rigid graph,arc addition operation,and path reversal operation,is proposed,which can quickly generate a feasible reconstructed communication topology after communication faults,thus ensuring the safety of the agents and maintaining the formation shape of persistent formation.Furthermore,a re-optimization algorithm of communication topology for persistent formation(ROA-CTPF),based on agent position exchange,is proposed,which can further obtain a reoptimized communication topology to minimize the formation communication cost while still maintaining the formation shape of persistent formation.The time complexities of these two algorithms are also analyzed.Finally,the effectiveness of the above algorithms is verified by numerical experiments.Compared with existing algorithms,FRA-CT-PF can always obtain feasible reconstructed communication topology in much less time under all communication fault scenarios,and ROA-CT-PF can obtain a reoptimized communication topology to further reduce the formation communication cost in a shorter time.

Dynamic Event-Triggered Consensus Control for Input Constrained Multi-Agent Systems With a Designable Minimum Inter-Event Time

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.

Three-dimensional impact angle constrained distributed cooperative guidance law for anti-ship missiles

This paper investigates the problem of distributed cooperative guidance law design for multiple anti-ship missiles in the three-dimensional(3-D)space hitting simultaneously the same target with considering the desired terminal impact angle constraint.To address this issue,the problem formulation including 3-D nonlinear mathematical model description,and communication topology are built firstly.Then the consensus variable is constructed using the available information and can reach consensus under the proposed acceleration command along the line-of-sight(LOS)which satisfies the impact time constraint.However,the normal accelerations are designed to guarantee the convergence of the LOS angular rate.Furthermore,consider the terminal impact angle constraints,a nonsingular terminal sliding mode(NTSM)control is introduced,and a finite time convergent control law of normal acceleration is proposed.The convergence of the proposed guidance law is proved by using the second Lyapunov stability method,and numerical simulations are also conducted to verify its effectiveness.The results indicate that the proposed cooperative guidance law can regulate the impact time error and impact angle error in finite time if the connecting time of the communication topology is longer than the required convergent time.

Distributed Secondary Control of AC Microgrids With External Disturbances and Directed Communication Topologies:A Full-Order Sliding-Mode Approach

This paper addresses the problem of distributed secondary control for islanded AC microgrids with external disturbances.By using a full-order sliding-mode(FOSM)approach,voltage regulation and frequency restoration are achieved in finite time.For voltage regulation,a distributed observer is proposed for each distributed generator(DG)to estimate a reference voltage level.Different from some conventional observers,the reference voltage level in this paper is accurately estimated under directed communication topologies.Based on the observer,a new nonlinear controller is designed in a backstepping manner such that an FOSM surface is reached in finite time.On the surface,the voltages of DGs are regulated to the reference level in finite time.For frequency restoration,a distributed controller is further proposed such that a constructed FOSM surface is reached in finite time,on which the frequencies of DGs are restored to a reference level in finite time under directed communication topologies.Finally,case studies on a modified IEEE 37-bus test system are conducted to demonstrate the effectiveness,the robustness against load changes,and the plug-and-play capability of the proposed controllers.

Coordinated Control Strategy for Harmonic Compensation of Multiple Active Power Filters

In order to minimize the harmonic distortion rate of the current at the common coupling point,this paper proposes a coordinated allocation strategy of harmonic compensation capacity considering the performance of active power filters(APF).On the premise of proportional distribution of harmonic compensation capacity,the harmonic compensation rate of each APF is considered,and the harmonic current value of each APF to be compensated is obtained.At the same time,the communication topology is introduced.Each APF takes into account the compensation ability of other APFs.Finally,three APFs with different capacity and performance are configured at the harmonic source to suppress the same harmonic source,and the harmonic distortion rate is reduced to 1.73%.The simulation results show that the strategy can effectively improve the compensation capability of the multiple APF cascaded system to the power grid without increasing the installed capacity.

Synchronising second-order multi-agent systems under dynamic topology via reference model-based algorithm

This paper revisits the synchronisation problem for second-order multi-agent systems(MASs)under dynamically changing communication topology.By employing the reference model-based synchronisation algorithm,it is finally shown that synchronisation for both the position and velocity states can be achieved if the union of the communication topologies has a directed spanning tree frequently enough.This extends the existing results obtained for second-order MASs which exploits mild communication topology condition guaranteeing the synchronisation to a more general case.Convergence analysis is successfully performed by exploiting the product properties of row-stochastic matrices,which can also provide us with an estimate the convergence rate towards the synchronisation.

Distributed Flocking Algorithm for Multi-UAV System Based on Behavior Method and Topological Communication

There are many interesting flocking phenomena in nature,such as joint predation and group migration,and the intrinsic communication patterns of flocking are essential for studying group behavior.Traditional models of communication such as the pigeon flock model and the wolf pack model define all agents within a perceptual distance as the neighborhoods,and some models have fixed communicating numbers.There is a significant impact on the quality of the flocking formation when encountering poor initial state of the flocking,multiple obstacles,or loss of certain agents.To solve this problem,this paper proposes a local communication model with nearest agents in four directions.Based on this model and behavioral method,two distributed flocking formation algorithms are designed in this paper for different scenarios,namely the flocking algorithm and the circular formation algorithm.Numerical simulation results show that the flocking can pass through the obstacle area and re-formation smoothly,and also the formation quality of the flocking is better compared with the traditional communication model.