分布式多无人机的时变编队非线性控制设计

研究了基于分布式通信网络的多无人机时变编队控制问题,考虑到外界扰动对多无人机协同编队系统的影响,提出一种新的连续非线性鲁棒编队控制方法.首先基于一致性方法构造了分布式无人机编队误差系统,降低了编队控制器对全局编队信息的要求;然后采用一种基于误差符号函数积分的鲁棒控制算法补偿未知外界扰动的影响,提高了无人机编队系统的鲁棒性,并基于Lyapunov分析的方法,证明了多无人机编队误差的半全局渐进收敛性;最后在四旋翼无人机编队实验平台上进行了多无人机时变编队的实时实验验证,实验结果表明,所提出的分布式编队控制算法可以实现多无人机时变编队控制,且具有较好的协同性能和抗干扰能力.     

存在时延的分布式无人机编队控制方法

多无人机协同是未来无人机应用的重要方式,多无人机编队作为多无人机协同的重要技术和研究热点也已引起越来越多关注,分布式无人机相较于集中式具有灵活性好、鲁棒性强,对通信及计算机性能要求低等优点;针对无人机的非线性动力学模型,在有向固定拓扑的条件下,运用高阶一致性理论解决无人机系统的分布式编队问题;基于Lyapunov稳定性原理,利用线性矩阵不等式(LMI),分别得出在具有时变时延导数信息及无导数信息情况下的稳定性充分条件;最后,仿真验证了这种编队控制方法的有效性;研究结果表明,利用文章所提出的方法控制无人机编队飞行,在满足稳定性的前提下,无人机系统能够形成稳定的编队,并达到预期速度。     

基于编队技术的无人机飞行控制策略研究

历经多年的发展,无人机(UAV)从无到有,相关技术也日益完善。同时,人们对无人机提出了越来越高的要求,需要无人机承担的任务越也来越复杂。单架无人机所具备的性能早已不能匹配各种新任务的要求,因此,多无人机协同编队成为了无人机技术最重要的发展趋势。相较于单个无人机,编队协同能够借助于多架无人机编队飞行,扩大作业范围、提高作业效率以及安全性,也使得无人机得到更加广泛的运用。     

无人机编队协同探测研究

未来战争是体系与体系的对抗;将多智能体技术和信息融合技术引入无人机编队系统中,构建出无人机编队协同探测任务规划体系和编队协同探测信息融合体系,并分析了该体系的结构.进而探讨了基于多智能体技术的无人机编队协同探测策略;此外,结合无人机编队面对突发威胁的应对措施,阐述了协同探测策略的具体应用;该研究成果对其他多作战平台系统的协同作战也有一定的借鉴意义。     

基于分布式一致性的无人机编队控制方法

多无人机系统中,系统状态的一致性是实现多无人机协同控制的基础,针对多无人机中存在的三维空间编队控制问题,提出一种分布式一致性的无人机编队协同控制方法。在主机-从机组成的多无人机系统的基础上,引入分布式结构,设计无人机控制系统模型并建立无人机编队协同机制。根据协同机制设计基于一致性算法的协同编队控制器、基于匈牙利算法的任务分配策略以及避障策略。分别在简易模拟器和基于ROS-Gazebo的实景模拟器中仿真验证了协同控制方法的有效性。结果表明：无人机群能够有效地完成协同编队任务,并且可以通过调整层次结构进行有效编队重构。     

基于一致性的多无人机编队算法研究

多无人机协同编队是无人机技术发展的重要方向,相比于单架无人机,编队协同能够增大搜索面积,提高无人机执行任务的效率;为了提高编队控制算法的控制效果和执行效率,以一致性理论为基础,针对无人机的特点和实际飞行情况,设计了改进的一致性编队控制算法,对一致性变量的边界问题进行平滑设计以及限幅处理,设计了σ-范数来调整合适的控制量,通过分段规划获得最佳的轨迹控制效果,并在控制协议中加入对目标点控制,同时对控制算法中的参数进行优化设计,从而实现无人机一致性的稳定控制;最后根据无人机领航—跟随的控制逻辑设计了一致性编队算法,实现了不同紧密编队队形任务;仿真结果表明了经过改进的一致性编队控制算法的有效性。     

无人机集群编队自组网可靠性评估

针对无人机集群编队自组网的可靠性评估问题,考虑无人机集群编队在执行任务时对信息交互的时效性需求,提出一种自组网可靠性评估方案.首先,分析消息传输的可用时间;其次,通过排队论建立消息传输延迟模型以计算消息传输所需时间;然后,以消息传输所需时间小于可用时间的概率作为评估指标建立消息传输可靠性计算模型,进而为无人机集群编队提供一个动态可靠性评估框架以适应集群编队体系配置和环境变化的随机性与时变特性;最后,仿真分析在不同传输任务需求下,编队构型、无人机数量、编队缩放因子、传输速率、信息交互强度以及环境干扰对消息传输可靠性的影响.仿真结果可以为集群编队的队形设计以及集群编队的体系配置提供一定参考依据.     

基于空中自组网的导调通信网络系统设计

近年来,随着无人机与无线自组网技术的不断发展,二者结合的无人机自组网作为空中自组网技术的一个重要组成,在越来越多的领域展现出了广泛应用前景。本文针对当前基地化训练中导调信息系统主要依托于固定基础设施,从而导致在向全域作战转型要求下基地化训练的广域延伸性和灵活机动性不足问题,通过分析研究空中自组网的技术特点及应用优势,结合提升基地化训练中全域全时导调评估能力的实际需求,提出一种基于空中自组网的机动导调通信网络设计构想,并探讨了空中自组网在机动导调通信保障中的几种典型应用场景,为丰富补充基地化训练中的机动导调通信保障手段提供参考与借鉴。     

基于多任务的无人机编队控制研究

考虑到多架无人机编队飞行的特点,将松散编队及协同思想应用到紧密编队控制中,提出了一个三架无人机协同作战编队的飞行控制系统设计方法;在编队飞行动力学模型的基础上,设计了基于特征结构配置的无人机横侧向控制律,进行指定航路的飞行控制;然后,设计编队控制器,两架僚机可紧紧跟随长机并保持队形稳定;仿真结果表明,设计的控制器可以控制多架无人机进行紧密编队飞行,具有一定的实用性和推广价值。     

基于改进势场法的无人机编队协同避障控制算法

为了解决多无人机存在的自碰撞与障碍碰撞及编队通信架构等问题,在二阶模型的编队系统基础上,提出一种由图论和人工势场理论相结合的分布式编队控制策略。依据运动学原理建立无人机模型,以固定无向的通信拓补结构为基础,引入分段思想、旋转力、机间势场力来改进势场合力函数,以解决可能出现的目标不可达、死锁、编队安全问题,精准实现编队避障、避碰与航迹预规划;根据一致性理论对无人机状态误差进行修正,设计编队协同避障控制律以实现期望状态一致与航迹规划;通过构造Hamilton函数与反证法进行稳定收敛性分析,证明所提出控制算法的收敛一致性。通过仿真结果表明,无人机编队能够有效进行避障并快速达到期望一致。     

Modeling and analysis of trust management with trust chain optimization in mobile ad hoc networks

We develop and analyze a trust management protocol for mission-driven group communication systems in mobile ad hoc networks using hierarchical modeling techniques based on stochastic Petri nets. Trust among mobile nodes is crucial for team collaborations with new coalition partners without prior interactions for mission-driven group communication systems in battlefield situations. In addition, ensuring a certain level of trust is also critical for successful mission completion. Our work seeks to identify the optimal length of a trust chain among peers in a trust web that generates the most accurate trust levels without revealing risk based on a tradeoff between trust availability and path reliability over trust space. We define a trust metric for mission-driven group communication systems in mobile ad hoc networks to properly reflect unique characteristics of trust concepts and demonstrate that an optimal trust chain length exists for generating the most accurate trust levels for trust-based collaboration among peers in mobile ad hoc networks while meeting trust availability and path reliability requirements.     

A survey of secure wireless ad hoc routing

Ad hoc networks use mobile nodes to enable communication outside wireless transmission range. Attacks on ad hoc network routing protocols disrupt network performance and reliability. The article reviews attacks on ad hoc networks and discusses current approaches for establishing cryptographic keys in ad hoc networks. We describe the state of research in secure ad hoc routing protocols and its research challenges.     

Cost-effective mobile ad hoc networks management

As there are more and more mobile devices in use, different mobile networking models such as ad hoc or mesh are attracting a large research interest. Self-organizing mobile ad hoc networks (MANET) allow devices to share their services and resources without any central administration or Internet support. In this respect they can become the backbone of the wireless grid or the gateway to existing grids. To achieve these goals, MANET management must be as effective as that of wired networks. This is, however, a challenging task due to network features like mobility, heterogeneity, limited resources of hosts and feeble communication. This paper presents a set of simple, cost-effective and resilient procedures for the basic tasks of MANET creation and management.     

数字家庭无线控制网络组网策略研究

在数字家庭中,传统移动自组网技术比较复杂.为此,提出一套适用于数字家庭无线控制网络系统的组网策略.分析数字家庭无线控制网络特点,引入一次成型机制和局部修复机制,利用硬件节点、指令帧格式完成组网策略的设计.实验结果表明,该策略的组网效果较好,能满足数字家庭的实用性要求.     

Reliable and Energy-Efficient Routing for Static Wireless Ad Hoc Networks with Unreliable Links

Energy efficient routing and power control techniques in wireless ad hoc networks have drawn considerable research interests recently. In this paper, we address the problem of energy efficient reliable routing for wireless ad hoc networks in the presence of unreliable communication links or devices or lossy wireless link layers by integrating the power control techniques into the energy efficient routing. We consider both the case when the link layer implements a perfect reliability and the case when the reliability is implemented through the transport layer, e.g., TCP. We study the energy efficient unicast and multicast when the links are unreliable. Subsequently, we study how to perform power control (thus, controlling the reliability of each communication link) such that the unicast routings use the least power when the communication links are unreliable, while the power used by multicast is close to optimum. Extensive simulations have been conducted to study the power consumption, the end-to-end delay, and the network throughput of our proposed protocols compared with existing protocols.     

基于签密的Ad Hoc网络密钥管理

AdHoc网络可以不依赖于现有网络基础设施,快速搭建起一个移动通信网络。然而它的灵活特性又使其安全性面临着严峻的挑战。文章首先分析了AdHoc网络的安全性,然后回顾了AdHoc网络安全性关键技术———密钥管理的研究现状,接着基于签密方案和门限密码方案给出一种新的AdHoc网络密钥管理方案。方案中不需要公钥证书的存在,用户以自己的身份标识作为公钥,极大地降低了用户终端计算、存储能力的需求和系统密钥管理的通信开销,而且可以实现用户的身份认证和私钥的周期性更新。     

Modelling and performance analysis of multi-hop ad hoc networks

Mobile ad hoc networks are becoming very attractive and useful in many kinds of communication and networking applications. Due to the advantage of numerical analysis, analytical modelling formalisms, such as stochastic Petri nets, queuing networks and stochastic process algebra have been widely used for performance analysis of communication systems. To the best of our knowledge, there is no previous analytical study that analyses the performance of multi-hop ad hoc networks, where mobile nodes move according to a random mobility model in terms of the end-to-end delay and throughput. This work presents a novel analytical framework developed using stochastic reward nets for modelling and analysis of multi-hop ad hoc networks, based on the IEEE 802.11 DCF MAC protocol, where mobile nodes move according to the random waypoint mobility model. The proposed framework is used to analyse the performance of multi-hop ad hoc networks as a function of network parameters such as the transmission range, carrier sensing range, interference range, number of nodes, network area size, packet size, and packet generation rate. The proposed framework is organized into several models to break up the complexity of modelling the complete network, and make it easier to analyse each model as required. The framework is based on the idea of decomposition and fixed point iteration of stochastic reward nets. The proposed models are validated using extensive simulations.     

Ad Hoc网络安全

Ad Hoc网络是针对移动主机提出的一种新型无线网络范例，与传统的移动无线网络不同，它不依赖任何固定设备。设计这种网络的一项主要挑战就是抵抗攻击的脆弱性。在这篇文章中，我们主要研究Ad Hoc网络所面临的威胁以及要达到的安全目标。我们找出这种新型网络环境下面临的新的挑战，并设计出新的方法以保证网络的正常通信。进一步地说，我们利用Ad Hoc网络内在的冗余(节点之间存在多条路线)来防止攻击。     

DEVS modeling of mobile wireless ad hoc networks

Ad hoc networks are self-organizing wireless systems conformed by cooperating neighboring nodes that conform networks with variable topology. Analyzing these networks is a complex task due to their dynamic and irregular nature. Cellular Automata (CA), a very popular technique to study self-organizing systems, can be used to model and simulate ad hoc networks, as the modeling technique resembles the system being modeled. Cell-DEVS was proposed as an extension to CA in which each cell in the system is considered as a DEVS model. The approach permits defining models with asynchronous behavior, and to execute them with high efficiency. We show how these techniques can be used to model mobile wireless ad hoc networks, making easy model definition, analysis and visualization of the results. The use of Cell-DEVS permitted us to easily develop new experiments, which allowed us to extend routing techniques for inter-networking and multicast routing, while permitting seamless integration with traditional networking models.     

超高速移动空 空宽带通信网及其物理层关键技术

随着航空事业的迅速发 展和空中通信终端的日益增加,构建支持超高速移动的空中宽带通信网络已成为未来航空通 信和军事通信发展的迫切需求。本文首先简要概述航空通信网络现状和发展趋势,在此基础 上指出实现超高速移动空 空宽带通信网络所面临的支持超高速移动、支持高数据传输速率 、支持远距离单跳链接、支持大规模自组网和多用户访问机制等挑战性问题,并分析其相互 制约关系。最后重点讨论空 空宽带通信网物理层关键技术及其研究现状,包括调制技术、 正交频分复用的峰均功率比抑制、频偏估计、信道估计与信道建模等。