Time-Variant Consensus Tracking Control for Networked Planar Multi-Agent Systems with Non-Holonomic Constraints

A time-variant consensus tracking control problem for networked planar multi-agent systems with non-holonomic constraints is investigated in this paper. In the time-variant consensus tracking problem, a leader agent is expected to track a desired reference input, simultaneously, follower agents are expected to maintain a time-variant formation. To solve the time-variant consensus tracking problem of planar multi-agent systems with non-holonomic constraints, a time-variant consensus tracking control strategy is designed on the basis of an unidirectional topology structure. One of main contributions of this paper is the time-variant consensus tracking protocol for general time-variant formations of planar multi-agent systems with non-holonomic constraints, the other main contribution of this paper is an active predictive control strategy, where predictions of agents are generated actively, so that the computational efficiency is improved than passive approaches. The proposed control strategy is verified by two types of time-varying formations of wheeled mobile robots, and the experimental results show that the proposed control strategy is effective for general time-variant consensus tracking problems of planar multi-agent systems with non-holonomic constraints in local and worldwide networked environments.     

降低时间延迟的紫外光通信系统设计

针对紫外光大气传输理论和非直视单散射模型,分析了大气信道对紫外光通信的影响,并在不同参数条件下,对大气信道所产生的时间延迟进行了定量仿真。仿真结果表明：时,可延迟／疃通信距离的增加而迅速增大,通信距离增加1km,时间延迟增加约2倍;时间延迟随发射和接收仰角的增加而增加,且发射仰角对时间延迟的影响大于接收仰角;时问延迟压壅发射束散角和接收视场角的增咖而减小。因此,为减小通信系统的时间延迟,在紫外光通信系统设计时,应尽量减小系统的发射仰角和接收仰角,增加系统的发射束散角和接收视场角。     

Generalized Consensus of Discrete-Time Multi-Agent Systems with Directed Topology and Communication Delay

Journal of Systems Science and Complexity - Compared with traditional consensus, this paper studies the generalized consensus problem for discrete-time multi-agent systems with directed topology...     

The Irregular Linear Quadratic Control Problem for Deterministic Case with Time Delay

This study deals with the irregular linear quadratic control problem governed by continuous time system with time delay. Linear quadratic(LQ) control for irregular Riccati equation with time delay remains challenging since the controller could not be solved from the equilibrium condition directly. The merit of this paper is that based on a new approach of ‘two-layer optimization', the controller entries of irregular case with time delay are deduced from two equilibrium conditions in two different layers, which is fundamentally different from the classical regular LQ control. The authors prove that the irregular LQ with time delay is essentially different from the regular case. Specifically,the predictive controller bases on the feedback gain matrix and the state is given in the last part. The presented conclusions are completely new to our best knowledge. Examples is presented to show the effectiveness of the proposed approach.     

虚拟时间反转镜Pattern时延差编码水声通信

提出虚拟时间反转镜(VTRM)算法,并基于Pattern时延差编码(PDS)水声通信体制,研究了VTRM在水声通信中的应用。PDS水声通信体制利用Pattern码元出现在码元窗的时延差值进行时延编码,具有稳健的通信性能。虚拟时间反转镜技术具有空间聚焦和信道均衡的性质,将其应用于PDS体制水声通信中,较时间反转镜(TRM)简单易行却又具有TRM的性质。计算机仿真结果表明,VTRM有效地抑制了水声信道严重的多途扩展对Pattern波形的畸变,提高了通信质量。     

虚拟现实系统中的时间延迟问题研究

研究了基于头盔显示器(HMD)的虚拟现实系统中的时间延迟问题。分析了延迟产生的原因,以及其对系统产生的影响。提出利用神经网络预测头部运动,由预测结果更新HMD显示,消除延迟。定义八种类型的头部运动,并选取头部的六自由度数据作为神经网络的训练样本。利用该方法,可以有效地补偿HMD系统中的时间延迟,消除使用者的眩晕感。     

时间依赖型多时间窗车辆路径问题研究

针对一类考虑城市交通拥堵情况的时间依赖型多时间窗车辆路径问题(time-dependent vehicle routing problem with multiple time windows,TD_VRPMTW),提出一种混合离散灰狼算法(hybrid discrete grey wolf optimizer,HDGWO)进行求解。在HDGWO中,设计了新的灰狼个体更新公式,采用基于客户排列的整数编码方式,使算法可直接在离散问题解空间中执行基于标准灰狼算法个体更新机理的全局搜索;设计了基于问题性质的种群初始化策略,用于生成具有高质量和多样性的初始种群;引入头狼信息交流公式,用于探索头狼形成的优质解空间;构造具有多种局部搜索操作的自适应变邻域局部搜索策略,用于增强算法的局部搜索能力。结果表明：HDGWO可有效求解TD_VRPMTW。     

S-TDMA协议点到点通信的仿真研究

介绍了自组织时分多址（S-TDMA）数据链协议中长传输过程和短传输过程两种点到点通信方式。利用网络仿真工具OPNETModeler，构建了S-TDMA数据链网络的仿真平台。在不同的业务量及重传参数下，对长传输过程和短传输过程的吞吐量、平均报文时延和平均报文丢弃率三种性能指标进行了仿真，并分析了仿真结果。     

Event-Triggered Consensus for Multiple Nonholonomic Systems

The paper investigates the consensus problem of multiple nonholonomic systems. Two event-triggered control strategies, one centralized and the other distributed, are developed, which can reduce the frequency of control updating. Under the proposed protocols, the multiple nonholonomic systems can achieve consensus, and the bound of inter-event time intervals is provided to illustrate that no Zeno behavior exists. Finally, numerical simulations are also provided to demonstrate the effectiveness of the proposed control strategies.     

一种低复杂度的频率、时延联合估计新方法

提出了一种基于子空间的正弦信号的频率、时延联合估计快速算法。首先给出一个PM(propagatormethod)算子 ,再由其分块矩阵构造一特殊的矩阵。由该矩阵的特征分解所得的特征矢量给出频率估计 ,而由其特征值及估计的频率得到时延估计。与现有的方法相比 ,由于该算法减少了一次特征分解 ,因而具有较低的计算复杂度。最后 ,用正弦信号及实测语音数据验证了该方法的性能     

Consensus of Heterogeneous Multi-Agent Systems with Intermittent Communication

This paper studies consensus of a class of heterogeneous multi-agent systems composed of first-order and second-order agents with intermittent communication. For leaderless multi-agent systems, we propose a distributed consensus algorithm based on the intermittent information of neighboring agents. Some sufficient conditions are obtained to guarantee the consensus of heterogeneous multi-agent systems in terms of bilinear matrix inequalities(BMIs). Meanwhile, the relationship between communication duration and each control period is sought out. Moreover, the designed algorithm is extended to leader-following multi-agent systems without velocity measurements. Finally, the effectiveness of the main results is illustrated by numerical simulations.     

时延优化的多信道MMSE均衡

无线通信系统中的接收机通过分数采样得到一个单输入多输出的多信道模型。研究了此多信道系统的均衡问题，给出了基于最小均方误差的多信道均衡器结构，其中每个子信道都对应一个最佳时延参数，理论分析给出了此最佳时延的一个较窄的取值范围。仿真与分析表明，在此范围内，各子信道时延取为子信道阶数加一时，系统性能并没有大的损失，可以接受，同时在这种情况下均衡器的实现结构大为简化。     

具有不同输入时延的二阶多智能体系统一致性

研究了具有不同时变输入时延的二阶连续多智能体系统的一致性问题。首先,通过变量转换,将系统的收敛性问题转化为误差系统的稳定问题;然后,通过对系统进行变换,将二阶系统稳定性问题转换为等价系统的稳定性问题。通过构造李雅普诺夫函数,基于线性矩阵不等式(LMI)的方法,给出在无向固定拓扑条件下,系统达到一致的充分条件。最后,仿真实例证明了结果的有效性。     

Global Practical Exponential Stabilization for One-Sided Lipschitz Systems with Time Delay

This paper addresses the practical stabilization problem for a class of one-sided Lipschitz nonlinear time delay systems with external disturbances. In case there is no perturbation, the exponential convergence of the observer was confirmed. When external disturbances appear in the system, a separation principle is established, and the authors show that the closed loop system is exponentially practical stable. By choosing a suitable Lyapunov-Krasovskii functional, the authors derive new sufficient conditions to guarantee the exponential stability of the systems. Finally, a physical model is performed to prove the efficiency and applicability of the suggested approach.

     

RHC-Based Consensus of Multi-Agent Systems with Simultaneous Packet Dropout and Input Delay

This paper is concerned with the multi-agent systems with both packet dropout and input delay. A novel receding horizon control (RHC) based consensus protocol is proposed by solving a distributed RHC based optimization problem. The novelty of the optimization problem lines in the involvement of the neighbours’ predictor information in the cost functions. Based on the derived RHC based consensus protocol, the necessary and sufficient condition for the mean-square consensus is obtained. In addition, the authors give a specific sufficient condition to guarantee the mean-square consensus.

     

Anti-synchronization of Chaotic Neural Networks with Time Delay

In the paper, the anti-synchronization problem of the general delayed chaotic neural networks is investigated. For the master and slave systems, we obtain a control law to achieve the state anti-synchronization of two identical chaotic neural networks. By using the Halanay inequality lemma and Lyapunov stability method, we derive a delay indepen- dent sufficient exponential anti-synchronization condition relative to the parameters of the systems and controller gain matrix. The condition is easily verified in practice. Finally, the theoretical results are applied to two delayed chaotic neural networks, and numerical simulations are given to demonstrate the performance of the proposed scheme throughout some examples.     

遗传算法在有时间窗车辆路径问题上的应用

本文用遗传算法求解有时间窗车辆路径问题,获得其近优解或最优解．传统的交叉算子如ＰＭＸ,ＥＲ和ＣＸ等对多约束问题的适用性受到限制,本文使用一种直观的编码方法,并提出基于优先关系的交叉算子．实验表明这种遗传算法能够有效地解决复杂的优化问题     

免疫算法在带时间窗的车辆路径问题中的应用

根据带时间窗的车辆路径问题的实际情况,提出了一种基于分组匹配的亲和力的计算方法.实验结果表明,免疫算法能有效地解决带时间窗的车辆路径问题.计算结果优于节约算法、分派算法、遗传算法.     

全系统网络延迟分析方法

针对飞行仿真系统实时性要求高的特点,构建了以以太网、实时反射内存网及现场总线技术等多种技术为主的飞行仿真系统分布式网络结构。分析了影响系统延迟的因素及其改进的方法,提出并建立了以太网、实时反射内存网及现场总线技术的延迟计算的数学模型,并提出了一种综合估算全系统时间延迟的方法。这些方法在相关的产品研发中得以运用并取得很好的实时性效果。     

Stochastic Optimal Control Problem in Advertising Model with Delay

This paper investigates the optimal control problem arising in advertising model with delay. The authors reformulate the problem in Hilbert space by stochastic evolution equation and consider the optimal control problem of controlled stochastic evolution system. The necessary and sufficient optimality conditions of the control are established. The proposed approach is different from most existing studies of optimal advertising policy problem with delay. These results are applied to the optimal advertising policy problem under two different structures and the optimal advertising strategies are obtained.