基于事件触发的异构多智能体最优包含控制

针对异构多智能体系统的输出包含控制问题，提出一种基于边的事件触发最优控制协议，保证所有跟随者的输出能进入到由领航者的输出所形成的凸包中。同时，使系统达到最优性能，最小化控制代价。考虑到不是所有的跟随者都可获得领航者的信息，提出一种基于边的分布式事件触发观测器，估计领航者输出形成的凸包内点的轨迹。设计加权代价函数评价包含控制的性能，并将输出包含问题转化为最优状态反馈控制设计问题。利用贝尔曼方程和黎卡提方程，给出异构多智能体系统最优输出包含控制的参数设计。选择不同类型的机器人构成多智能体系统，验证算法的有效性。     

Distributed event-triggered adaptive control for second-order nonlinear uncertain multi-agent systems

In this paper, the event-triggered consensus control problem for nonlinear uncertain multi-agent systems subject to unknown parameters and external disturbances is considered. The dynamics of subsystems are second-order with similar structures, and the nodes are connected by undirected graphs. The event-triggered mechanisms are not only utilized in the transmission of information from the controllers to the actuators, and from the sensors to the controllers within each agent, but also in the communication between agents. Based on the adaptive backstepping method, extra estimators are introduced to handle the unknown parameters, and the measurement errors that occur during the event-triggered communication are well handled by designing compensating terms for the control signals. The presented distributed event-triggered adaptive control laws can guarantee the boundness of the consensus tracking errors and the Zeno behavior is avoided. Meanwhile, the update frequency of the controllers and the load of communication burden are vastly reduced. The obtained control protocol is further applied to a multi-input multi-output second-order nonlinear multi-agent system, and the simulation results show the effectiveness and advantages of our proposed method.     

Adaptive event-triggered distributed optimal guidance design via adaptive dynamic programming

In this paper, the multi-missile cooperative guidance system is formulated as a general nonlinear multi-agent system. To save the limited communication resources, an adaptive eventtriggered optimal guidance law is proposed by designing a synchronization-error-driven triggering condition, which brings together the consensus control with Adaptive Dynamic Programming(ADP) technique. Then, the developed event-triggered distributed control law can be employed by finding an approximate solution of eve...     

多导弹系统协同攻击机动目标分布式制导律

基于增强型比例导引律和分布式网络同步理论,设计了一类攻击机动目标的多导弹系统分布式协同制导律。该制导律由各导弹本地制导律和分布式协同导引策略两部分组成:本地制导律为增强型比例导引律,进一步利用代数图论和非线性系统一致性理论,得到基于邻接个体信息交互的分布式协同制导律,实现多导弹对目标的同时协同攻击;该分布式协同制导律仅需视距内各相邻导弹间互相传输各自的状态信息,算法具有较低的通信代价和较好的可扩展性。最后给出了相关数值仿真算例,仿真结果验证了算法的有效性。     

具有动态领导者的多智能体系统分组一致性控制

对一类具有动态领导者的非线性多智能体系统的一致性进行研究，解决了领导-跟随一致性控制问题。首先，考虑到多目标任务中广泛存在的合作-竞争机制和领导者的控制输入非零的情况，基于邻居智能体的相对状态信息，设计了一类分布式的分组一致性控制器。通过在所设计的控制器中增加补偿项，解决了由领导者非零控制输入引出的问题。引入了一类Lipschitz-like条件，解决了非线性项在实现分组一致时所带来的困难。其次，利用图论和构造Lyapunov函数，通过求解代数Riccati方程得出了系统实现分组一致性的充分条件，并基于所设计的控制器实现了多智能体系统动态领导-跟随的分组一致性控制。最后，通过数值仿真和结果分析验证了所提出控制方案的有效性和可行性。     

基于分布式自适应的多智能体容错一致性控制

针对"领航者-跟随者"的多智能体编队，由于领航者系统出现故障引起编队通讯中断而不能完成任务的问题，提出了一种基于一致性理论的分布式自适应控制方法，用于解决该问题。首先，以一个位于顶点的智能体作为领航者，其余3个位于同一条线上的智能体作为跟随者，由此所构成的三角形编队作为被控对象。其中，领航者速度方向作为编队的前行方向，跟随者位于领航者之后。其次，基于图论，对智能体局部信息参数进行分布式自适应更新，并设计分布式自适应控制律，用于弥补多智能体编队中领航者故障所造成的影响。同时，根据相邻智能体的局部信息，设计整体分布式自适应容错控制律，进一步通过构建合理的Lyapunov函数，证明所设计控制器的稳定性，以及"领航者-跟随者"之间相对横向以及相对纵向的距离误差均收敛于固定常数。最后，仿真验证表明：所提出的自适应控制方法具有良好的鲁棒性，这也为工程实践提供了理论依据。     

Spacecraft formation-containment flying control with time-varying translational velocity

This paper investigates the problem of Spacecraft Formation-Containment Flying Control (SFCFC) when the desired translational velocity is time-varying. In SFCFC problem, there are multiple leader spacecraft and multiple follower spacecraft and SFCFC can be divided into leader spacecraft’s formation control and follower spacecraft’s containment control. First, under the condition that only a part of leader spacecraft can have access to the desired time-varying translational velocity, a velocity estimator is designed for each leader spacecraft. Secondly, based on the estimated translational velocity, a distributed formation control algorithm is designed for leader spacecraft to achieve the desired formation and move with the desired translational velocity simultaneously. Then, to ensure all follower spacecraft converge to the convex hull formed by the leader spacecraft, a distributed containment control algorithm is designed for follower spacecraft. Moreover, to reduce the dependence of the designed control algorithms on the graph information and increase system robustness, the control gains are changing adaptively and the parametric uncertainties are handled, respectively. Finally, simulation results are provided to illustrate the effectiveness of the theoretical results.     

Formation tracking control for time-delayed multi-agent systems with second-order dynamics

In this paper, formation tracking control problems for second-order multi-agent systems (MASs) with time-varying delays are studied, specifically those where the position and velocity of followers are designed to form a time-varying formation while tracking those of the leader. A neigh-boring relative state information based formation tracking protocol with an unknown gain matrix and time-varying delays is presented. The formation tracking problems are then transformed into asymptotically stable problems. Based on the Lyapunov-Krasovskii functional approach, condi-tions sufficient for second-order MASs with time-varying delays to realize formation tracking are examined. An approach to obtain the unknown gain matrix is given and, since neighboring relative velocity information is difficult to measure in practical applications, a formation tracking protocol with time-varying delays using only neighboring relative position information is introduced. The proposed results can be used on target enclosing problems for MASs with second-order dynamics and time-varying delays. An application for target enclosing by multiple unmanned aerial vehicles (UAVs) is given to demonstrate the feasibility of theoretical results.     

Semi-global leader-following consensus-based formation flight of unmanned aerial vehicles

In this paper, we investigate a formation control problem of multi-agent systems(specifically a group of unmanned aerial vehicles) based on a semi-global leader-following consensus approach with both the leader and the followers subject to input saturation. Utilizing the low gain feedback design technique, a distributed static control protocol and a distributed adaptive control protocol are constructed. The former solves the problem under an assumption that the communication network is undirecte...     

QFT force loop design for the aerodynamic load simulator

A dynamic load simulator which can reproduce on-ground the aerodynamic hinge moment of a control surface is an essential rig for conducting performance and stability tests of aircraft actuation systems. The hinge moment varies widely over the flight envelope, depending on the specific flight condition and maneuvering status. To replicate the wide spectrum of this hinge moment variation within some accuracy hounds, a force controller is designed based on the Quantitative Feedback Theory (QFT). A dynamic model of the load actuation system Is derived, and compared with experimental results. Through this comparison, a nominal model of the load actuation system with some uncertainty bounds is developed. The efficacy of the QFT force controller is verified by a numerical simulation, in which combined aircraft dynamics, flight control law and hydraulic actuation system dynamics of the aircraft control surface are considered     

Periodic event-triggered formation control for multi-UAV systems with collision avoidance

In this paper, periodic event-triggered formation control problems with collision avoidance are studied for leader–follower multiple Unmanned Aerial Vehicles (UAVs). Firstly, based on the Artificial Potential Field (APF) method, a novel sliding manifold is proposed for controller design, which can solve the problem of collision avoidance. Then, the event-triggered strategy is applied to the distributed formation control of multi-UAV systems, where the evaluation of the event condition is continuous. In addition, the exclusion of Zeno behavior can be guaranteed by the inter-event time between two successive trigger events have a positive lower bound. Next, a periodic event-triggered mechanism is developed for formation control based on the continuous event-triggered mechanism. The periodic trigger mechanism does not need additional hardware circuits and sophisticated sensors, which can reduce the control cost. The stability of the control system is proved by the Lyapunov function method. Finally, some numerical simulations are presented to illustrate the effectiveness of the proposed control protocol.     

圆形轨迹导引下的无人机事件触发抗干扰环绕控制

针对内部不确定性以及外部环境摄动的目标环绕控制问题,在基于反步法的双层制导框架下,利用级联控制思想,提出了一种圆形轨迹导引下的四旋翼无人机事件触发抗扰环绕控制方法。在轨迹回路中,构建了可满足持续激励条件的目标位置估计器,保证仅通过视线方位角就能获取可满足最终一致有界条件的目标估计项。随后,基于目标的位置估计结果,设计了目标环绕控制律生成线速度指令,并通过方向向量场验证了该环绕制导律的有效性,消除了现有李雅普诺夫向量场制导(LVFG)对相对位置和目标速度的依赖。在姿态回路中,通过采用扩张状态观测器(ESO)补偿系统的集总不确定性,设计了基于相对阈值事件触发控制的姿态控制器,在有效降低控制器到执行机构之间信号传输频率的同时,实现了四旋翼无人机对静止/移动目标环绕。然后,借助输入状态稳定性定理证明了系统的稳定性。仿真结果表明,所提控制方案能够实现圆形轨迹导引下四旋翼无人机对静止/移动目标的环绕监视。     

Event-triggered and consensus-based attitude tracking alignment for discrete-time multiple spacecraft system exploiting interference

This paper presents a discrete-time attitude control strategy with equi-global practical stabilizability for aligning the attitude of multiple spacecraft to a predesigned configuration according to a time-variant reference. By utilizing the interference of the wireless channel, the communication scheme designed in this paper can save communication resources, amount of computation, and energy proportionally to the number of spacecraft. The exact discrete-time model and approximate discrete-time model of the consensus-based spacecraft tracking system are given. Then the framework for the design of an event-triggered control scheme for the exact discrete-time system via its approximate models is developed, which avoids the periodic actuation, and Zeno behavior is proved to be excluded. Furthermore, the control scheme can handle the presence of the unknown fading channel. Finally, simulation results are presented to demonstrate the effectiveness of the control strategy.     

Consensus based on learning game theory with a UAV rendezvous application

Multi-agent cooperation problems are becoming more and more attractive in both civilian and military applications. In multi-agent cooperation problems, different network topologies will decide different manners of cooperation between agents. A centralized system will directly control the operation of each agent with information flow from a single centre, while in a distributed system, agents operate separately under certain communication protocols. In this paper, a systematic distributed optimization approach will be established based on a learning game algorithm.The convergence of the algorithm will be proven under the game theory framework. Two typical consensus problems will be analyzed with the proposed algorithm. The contributions of this work are threefold. First, the designed algorithm inherits the properties in learning game theory for problem simplification and proof of convergence. Second, the behaviour of learning endows the algorithm with robustness and autonomy. Third, with the proposed algorithm, the consensus problems will be analyzed from a novel perspective.     

Confluence of navigation, communication, and control in distributedspacecraft systems

This research details the development of technologies and methodologies that enable distributed spacecraft systems by supporting integrated navigation, communication, and control. Operating at the confluence of these critical functions produces capabilities needed to realize the promise of distributed spacecraft systems, including improved performance and robustness relative to monolithic space systems. Navigation supports science data association and data alignment for distributed aperture sensing, multipoint observation, and co-observation of target regions. Communication enables autonomous distributed science data processing and information exchange among space assets. Both navigation and communication provide essential input to control methods for coordinating distributed autonomous assets at the interspacecraft system level and the intraspacecraft affector subsystem level. A technology solution to implement these capabilities, the Crosslink Transceiver, is also described. The Crosslink Transceiver provides navigation and communication capability that can be integrated into a developing autonomous command and control methodology for distributed spacecraft systems. A small satellite implementation of the Crosslink Transceiver design is detailed and its ability to support broad distributed spacecraft mission classes is described     

基于相对方位信息和单间距测量的多智能体编队协同控制

由多个载体组成的多智能体系统对复杂环境具有更高的适应性,能够完成传统单个载体无法完成的任务。针对多智能体编队集结与队形移动跟踪问题,提出了一种改进的多智能体编队协同控制新算法。首先,以拒止环境下跟随智能体仅能通过光学传感器测量相对方位信息为任务背景,针对"领导者——第一跟随者"结构的多智能体编队,提出了基于相对方位信息与单间距测量的控制器,使得第一跟随者智能体可以追随移动的领导者智能体,并且可以通过改变与领导者智能体的间距对编队整体队形进行缩放控制。其次,提出一种了改进的分布式控制律,使得其他跟随者智能体可以仅通过两个相对方位信息完成编队飞行。然后,根据Lyapunov第二方法,构建了系统的能量函数,验证了所提出算法的稳定性。最后,通过数值仿真实验对所提算法进行了验证。仿真结果表明,基于该控制律多智能体系统能够完成编队集结、队形缩放和编队飞行的任务。     

基于固定阈值事件触发扩张状态观测器的多智能体协同目标环绕控制

针对复杂多扰环境下面向未知运动目标的多智能体对峙跟踪问题,提出了一种基于固定阈值事件触发扩张状态观测器(FTESO)的多智能体协同目标环绕控制方法.首先,建立了智能体与目标的相对运动模型,将目标加速度、模型非线性、环境摄动视为集总干扰,利用量测的相对位置信息构造可降低测量端状态更新频次的FTESO,以实现在非周期采样条...     

基于消息的分布式工作流执行系统研究

工作流实例的执行处于整个管理系统的核心地位.传统的工作流管理系统多是采用客户机/服务器模式的集中运行,针对这种集中式工作流执行系统,研究了分布式的工作流执行方法,结合分布计算和异步消息通讯技术,提出了一种分层的工作流调度执行系统,将集中式系统中的业务处理、通讯压力分散到各个执行节点,最后给出了一个基于J2EE的原型系统.     

Virtual target guidance-based distributed model predictive control for formation control of multiple UAVs

The paper proposes a Virtual Target Guidance (VTG)-based distributed Model Predictive Control (MPC) scheme for formation control of multiple Unmanned Aerial Vehicles (UAVs). First, a framework of distributed MPC scheme is designed in which each UAV only shares the information with its neighbors, and the obtained local Finite-Horizon Optimal Control Problem (FHOCP) can be solved by swarm intelligent optimization algorithm. Then, a VTG approach is developed and integrated into the distributed MPC scheme to achieve trajectory tracking and obstacle avoidance. Further, an event-triggered mechanism is proposed to reduce the computational burden for UAV formation control, which takes into consideration the predictive state errors as well as the convergence of cost function. Numerical simulations show that the proposed VTG-based distributed MPC scheme is more computationally efficient to achieve formation control of multiple UAVs in comparison with the traditional distributed MPC method.     

Distributed intelligent self-organized mission planning of multi-UAV for dynamic targets cooperative search-attack

This article studies the cooperative search-attack mission problem with dynamic targets and threats, and presents a Distributed Intelligent Self-Organized Mission Planning (DISOMP) algorithm for multiple Unmanned Aerial Vehicles (multi-UAV). The DISOMP algorithm can be divided into four modules: a search module designed based on the distributed Ant Colony Optimization (ACO) algorithm, an attack module designed based on the Parallel Approach (PA) scheme, a threat avoidance module designed based on the Dubins Curve (DC) and a communication module designed for information exchange among the multi-UAV system and the dynamic environment. A series of simulations of multi-UAV searching and attacking the moving targets are carried out, in which the search-attack mission completeness, execution efficiency and system suitability of the DISOMP algorithm are analyzed. The simulation results exhibit that the DISOMP algorithm based on online distributed down-top strategy is characterized by good flexibility, scalability and adaptability, in the dynamic targets searching and attacking problem.