通信拓扑切换下车辆队列分布式模型预测控制

考虑通信拓扑切换下异质非线性车辆队列系统协同控制问题,提出一种能够保证车辆队列稳定和弦稳定的分布式模型预测控制策略.先结合车辆队列动态通信拓扑切换过程,构建与时间相关的图函数,再利用邻居车辆状态信息描述平均协同代价函数,并将其引入局部滚动时域优化控制问题.进一步,应用平均停留时间概念和切换系统Lyapunov稳定性理论,建立通信拓扑切换下车辆队列闭环系统的内部稳定性和弦稳定性充分条件.最后通过两组典型交通场景的对比仿真验证本文策略的有效性.     

基于事件触发的拓扑切换异构多智能体协同输出调节

研究切换拓扑下线性异构多智能体系统的协同输出调节问题,并设计了一个基于事件触发的输出调节控制机制.设计的控制机制不仅可以实现智能体对外部系统的渐近跟踪和干扰抑制,还可以有效减少智能体之间的信息传递数量,从而降低通信负载减少网络能耗.最后通过仿真验证结论的有效性.     

带有控制受限的卫星编队飞行六自由度自适应协同控制

针对存在参数不确定性以及干扰的卫星编队飞行六自由度协同控制问题,提出了一种满足控制输入有界的自适应L2增益干扰抑制控制方法.该方法首先在不考虑干扰的条件下,针对卫星编队六自由度协同运动模型存在参数不确定性提出了一种自适应协同控制器;接着,考虑到系统存在干扰,进一步设计了具有L2增益干扰抑制能力且满足输入有界条件的自适应...     

牵制控制下的多智能体系统群一致性

本文研究了一类多智能体系统在牵制控制下的群一致性问题,提出了融合群内信息交互、群间信息交互和牵制控制器的一致性协议.对固定拓扑下的二群组智能体系统和切换拓扑下的多群组智能体系统,利用稳定性理论和图论分别给出了适用于任意拓扑结构的充要条件,使得智能体系统在所提协议和牵制控制器的联合作用下实现预期的群一致.针对拓扑图中含有生成树这一特例,分析了被施加牵制控制的智能体在结构中的具体位置.此外,对切换拓扑下进行非线性交互的多群组智能体系统,利用Lyapunov方法推导出一充分条件,得出只要对多智能体系统的一部分主体进行牵制控制,则所有智能体即可在所提协议和牵制控制器的作用下渐近收敛于各自的期望一致平衡点.最后,仿真例子验证了所提方法的有效性.     

大型超市制冷系统同步现象分析

在大型超市制冷系统耗能问题的研究中,由于系统通常采用分布式控制,控制方式往往忽视了各子系统之间的交互干扰而导致系统出现同步现象.将系统的非线性数学模型简化为一个二阶仿射切换系统模型,并在Matlab环境下进行了仿真,对系统的同步现象进行了分析.仿真结果表明,系统在运行过程中出现了同步现象,即各陈列柜温度趋于一致,各陈列柜蒸发器入口阀门的开闭状态趋于同步.通过分析,同步现象的出现使吸气总管的吸气压力出现了周期性较大的波动,容易造成压缩机频繁启停,增加了压缩机的损耗,不利于超市制冷系统的节能降耗.     

不确定分数阶多涡卷混沌系统自适应重复学习同步控制

研究了不确定分数阶多涡卷混沌系统的自适应重复学习同步控制问题.通过利用滞环函数,设计了一类参数可调的分数阶多涡卷混沌系统.针对这类分数阶多涡卷混沌系统,在考虑非参数化不确定性、周期时变参数化不确定性、常参数化不确定性和外部扰动情况下,提出了一种重复学习同步控制方案.利用自适应神经网络技术补偿了系统中的函数型不确定性,通过自适应重复学习控制技术处理了周期时变参数化不确定性,并利用自适应鲁棒学习项处理了神经网络逼近误差和干扰的影响,实现了主系统和从系统的完全同步.综合利用分数阶频率分布模型和类Lyapunov复合能量函数方法证明了同步误差的学习收敛性.数值仿真验证了所提方法的有效性.     

移动机器人编队自修复的切换拓扑控制

针对机器人缺失后的移动机器人编队自修复问题, 构建了结合切换拓扑和交互动力模型的移动机器人编队模型, 通过分析机器人缺失后的拓扑变化情况, 提出了网络切换拓扑控制, 该算法利用递归实现自修复, 并且是收敛的. 通过设计相应的分布式算法, 本文将拓扑控制转化为基于局部交互的递归自修复个体控制, 证明了编队自修复个体控制的稳定性. 最后针对编队任务, 通过仿真验证了切换拓扑控制的有效性, 和其他方法比较具有低恢复时间和低功率消耗的优点.     

网络攻击下一类非线性切换多智能体系统的安全自适应控制

针对一类控制方向未知的非线性切换多智能体系统, 本文研究了在不确定网络攻击下的安全控制问题. 网 络攻击破坏传感器真实数据, 导致系统真实信息无法获取且不能直接用于控制设计. 为此, 通过受攻击状态构建一 组新颖辅助变量来消除网络攻击造成的影响. 此外, 所研究的系统包含更一般的不确定性, 即未知控制方向, 未知常 值参数以及不确定攻击. 这些不确定性在设计过程中相互耦合. 利用Nussbaum型函数并设计自适应律补偿耦合后 的不确定性, 极大降低了系统复杂性. 通过系统性地迭代构造出共同Lyapunov函数, 提出了一套安全自适应控制方 法, 保证了受攻击系统在任意切换下达到渐近输出一致性. 最后, 数值仿真验证了该方法的有效性.     

有向图中模块化航天器系统相对轨道的自适应分布式一致性

基于多智能体系统一致性理论,对模块化航天器相对轨道的分布式一致性问题进行了研究.各模块之间的信息交互拓扑结构为更具一般性的有向图.当存在模块质量不确定性的情形下,设计了仅依赖模块自身及其邻近模块信息且无需模块间相对速度信息的自适应控制算法.针对模型中存在外部干扰的情形,通过引入带有时变自适应参数的变结构控制项,实现了对未知上界干扰的补偿,并且证明了闭环系统是渐近稳定的.此外,本文所设计的算法具有分布式的特点,不会因为模块数量的增多而增加所提算法的复杂度.最后对6个模块组成的模块化航天器的编队飞行进行了仿真分析,仿真结果表明本文设计的控制律是有效可行的.     

一类离散时间线性切换系统的二次鲁棒镇定

针对一类具有范数有界时变不确定性的离散时间线性切换系统,研究了其二次稳定化状态反馈控制律的设计问题.利用多李亚普诺夫函数法推导了在任意切换下二次稳定化控制律存在的充分条件,该条件被进一步等价地表示成线性矩阵不等式的可解性问题.同时它的解提供了二次稳定化控制律的一个参数化表示.仿真结果验证了所提方法的有效性.     

切换有向拓扑中的网络化Euler-Lagrange系统自适应同步控制（英文）

In this paper, the cooperative control problem of networked Euler-Lagrange systems with parametric uncertainties and unidirectional interaction is addressed under dynamically changing topology. As the communication graph evolves over time, a distributed control law via local effective interactions is designed. Adaptive techniques are used to deal with parametric uncertainties in the dynamics. With a continuous Lyapunov function, it is obtained that synchronization can still be achieved asymptotically as long as the union graph of the switching topologies has a directed spanning tree frequently enough. Extensions to disturbance rejection problems are also addressed using simple disturbance-observer or sliding mode control scheme. Illustrative examples with comparing simulation in the context of attitude synchronization of five non-identical spacecraft are further presented to show the effectiveness of the proposed cooperative control strategy.     

Synchronization of Heterogeneous Multi‐Agent Systems by Adaptive Iterative Learning Control

In this work, under a repeatable control environment, an adaptive iterative learning control method is applied to synchronize a group of uncertain heterogeneous agents. The agent dynamics are modeled by nonlinear equations, which contain both parametric and non‐parametric uncertainties. Furthermore, the uncertainties are assumed to be general nonlinear terms instead of the global Lipschitz functions. The communication among the followers is depicted by an undirected and connected graph, meanwhile, the virtual leader's trajectory is only accessible to a small portion of the followers. The proposed learning rules enable all the followers to learn and handle both parametric and non‐parametric uncertainties based on the local information such that the followers can synchronize their trajectories to the desired one. In comparison with the existing literature, most works assume first or second order nonlinear systems, and perfect initial conditions. In order to mitigate the identical initialization condition, the applicability of alignment condition and initial rectifying action are further explored. In addition, our developed algorithms can be applied to general high order nonlinear systems. Finally, synchronization examples of networked robotic manipulators are presented to demonstrate the effectiveness of the developed methods.     

Attitude Control of Multiple Rigid Bodies with Uncertainties and Disturbances

Decentralized attitude synchronization and tracking control for multiple rigid bodies are investigated in this paper. In the presence of inertia uncertainties and environmental disturbances, we propose a class of decentralized adaptive sliding mode control laws. An adaptive control strategy is adopted to reject the uncertainties and disturbances. Using the Lyapunov approach and graph theory, it is shown that the control laws can guarantee a group of rigid bodies to track the desired time-varying attitude and angular velocity while maintaining attitude synchronization with other rigid bodies in the formation. Simulation examples are provided to illustrate the feasibility and advantage of the control algorithm.      

Consensus in multi-agent systems with nonlinear uncertainties under a fixed undirected graph

This paper presents consensus algorithms by integrating cooperative control and adaptive control laws for multi-agent systems with unknown nonlinear uncertainties. An ideal multi-agent system without uncertainties is introduced first. The cooperative control law, based on an artificial potential function, is designed to make the ideal multi-agent system achieve consensus under a fixed and connected undirected graph. The presence of uncertainties will degenerate the performance, or even destabilize the whole multi-agent system. The L ₁ adaptive control law is therefore introduced to handle unknown nonlinear uncertainties. Two different consensus cases are considered: 1) normal consensus—where all agents reach an agreement on an initially undetermined position and velocity, and 2) consensus with a virtual leader—where all agents’ states converge to the virtual leader’s states. Under a fixed and connected undirected graph, the presented consensus algorithms enable the real multi-agent system to stay close to the ideal multi-agent system which achieves consensus with or without a virtual leader. Simulation results of 2-D consensus with nonlinear uncertainties are provided to demonstrate the presented algorithms.     

Robust synchronization of chaotic systems using slidingmode and feedback control

We propose a robust scheme to achieve the synchronization of chaotic systems with modeling mismatches and parametric variations. The proposed algorithm combines high-order sliding mode and feedback control. The sliding mode is used to estimate the synchronization error between the master and the slave as well as its time derivatives, while feedback control is used to drive the slave track the master. The stability of the proposed design is proved theoretically, and its performance is verified by some numerical simulations. Compared with some existing synchronization algorithms, the proposed algorithm shows faster convergence and stronger robustness to system uncertainties.     

Control and synchronization of chaotic systems using a novel indirect model reference fuzzy controller

This paper presents a robust indirect model reference fuzzy control scheme for control and synchronization of chaotic nonlinear systems subject to uncertainties and external disturbances. The chaotic system with disturbance is modeled as a Takagi–Sugeno fuzzy system. Using a Lyapunov function, stable adaptation laws for the estimation of the parameters of the Takagi–Sugeno fuzzy model are derived as well as what the control signal should be to compensate for the uncertainties. The synchronization of chaotic systems is also considered in the paper. It is shown that by the use of an appropriate reference signal, it is possible to make the reference model follow the master chaotic system. Then, using the proposed model reference fuzzy controller, it is possible to force the slave to act as the reference system. In this way, the chaotic master and the slave systems are synchronized. It is shown that not only can the initial values of the master and the slave be different, but also there can be parametric differences between them. The proposed control scheme is simulated on the control and the synchronization of Duffing oscillators and Genesio–Tesi systems.     

Exponential synchronization of nonlinear multi‐agent systems with time delays and impulsive disturbances

The problem of cooperative synchronization of nonlinear multi‐agent systems with time delays is investigated in this paper. Compared with the existing works about synchronization (or consensus) of multi‐agent systems, the method in this paper provides a more general framework by considering nonlinear multi‐agent systems with time delays and impulsive disturbances. The model in this paper is sufficiently general to include a class of delayed chaotic systems. Based on the Lyapunov stability theory and algebraic graph theory, sufficient conditions are presented to guarantee the cooperative exponential synchronization for these multi‐agent delayed nonlinear systems. These conditions are expressed in terms of linear matrix inequalities, which can easily be checked by existing software tools. It is seen that the Lyapunov functions must be constructed based on the graph topology to prove synchronization. The well‐known master–slave (drive‐response) synchronization of two chaotic delayed systems is a special case of this paper, and therefore, the results in this paper are also useful for practical applications in secure communication. Simulation results verify the effectiveness of the proposed synchronization control algorithm. Copyright © 2015 John Wiley & Sons, Ltd.     

Decentralized adaptive attitude synchronization of spacecraft formation

This paper studies adaptive attitude synchronization of spacecraft formation with possible time delay. By introducing a novel adaptive control architecture, decentralized controllers are developed, which allow for parameter uncertainties and unknown external disturbances. Based upon graph theory, Lyapunov stability theory and time-delay control theory, analytical tools are also provided. A distinctive feature of this work is to address the adaptive attitude synchronization with unknown parameters and coupling time delay in a unified theoretical framework, with general directed information flow. It is shown that arbitrary desired attitude tracking and synchronization with respect to a given reference can be attained. Simulation results are provided to demonstrate the effectiveness of the obtained results.     

Terminal滑模自适应控制实现一类不确定混沌系统的同步

应用Terminal滑模控制技术和选择指数趋近律来综合滑模控制器，实现一类混沌系统的状态同步．在控制器中引入一类简单的自适应律，用以在线估计界参数．该设计方案消除了滑模控制的到达阶段，状态始终保持在滑模面上，并能在有限时间内趋近于原点．与一般滑模控制同步实现相比，具有更小的同步时间和鲁棒性．通过对Duffing—Holmes系统的同步仿真，验证了该方法的可行性．     

Attitude synchronization control for a group of flexible spacecraft

To solve the problem of attitude synchronization for a group of flexible spacecraft during formation maneuvers, a distributed attitude cooperative control strategy is investigated in this paper. Based on the backstepping design and the neighbor-based design rule, a distributed attitude control law is constructed step by step. Using cascaded systems’ theory and graph theory, it is shown that the attitude synchronization is achieved asymptotically and the induced vibrations by flexible appendages are simultaneously suppressed under the proposed control law.