Cooperative Target Tracking of Multiple Autonomous Surface Vehicles Under Switching Interaction Topologies

This paper is concerned with the cooperative target tracking of multiple autonomous surface vehicles(ASVs)under switching interaction topologies.For the target to be tracked,only its position can be measured/received by some of the ASVs,and its velocity is unavailable to all the ASVs.A distributed extended state observer taking into consideration switching topologies is designed to integrally estimate unknown target dynamics and neighboring ASVs'dynamics.Accordingly,a novel kinematic controller is designed,which takes full advantage of known information and avoids the approximation of some virtual control vectors.Moreover,a disturbance observer is presented to estimate unknown time-varying environmental disturbance.Furthermore,a distributed dynamic controller is designed to regulate the involved ASVs to cooperatively track the target.It enables each ASV to adjust its forces and moments according to the received information from its neighbors.The effectiveness of the derived results is demonstrated through cooperative target tracking performance analysis for a tracking system composed of five interacting ASVs.

Parametric formation control of multiple nanosatellites for cooperative observation of China Space Station

This study proposes a parametric formation control method for the cooperative observation of the China Space Station(CSS)using multiple nanosatellites.First,a simplified geometrical model of the CSS is constructed using fundamental solids,such as the capsule body and cuboid.Second,the spacecraft formation configuration for the observation mission is characterized by a three-dimensional(3D)Lissajous curve using related design parameters under the full-coverage observation requirements of specific parts,such as the CSS connecting section and collision avoidance constraints.Third,a double-layer control law is designed for each nanosatellite,in which the upper layer is a distributed observer for recognizing the target formation configuration parameters,and the lower layer is a trajectory-tracking controller to make the nanosatellite converge to its temporary target position calculated from the upper layer’s outputs.The closed-loop control stability is proven under the condition that the communication network topology of the nanosatellite cluster contains a directed spanning tree.Finally,the control method is verified by numerical simulation,where the CSS connecting section is selected as the observation target,and ten small nanosatellites are assumed to perform the cooperative observation mission.The simulation results demonstrate that the double-layer control law is robust to single-point communication failures and suitable for the accompanying missions of large space objects with multiple nanosatellites.

Networked Cooperative Distributed Model Predictive Control Based on State Observer

Although distributed model predictive control has caused significant attention and received many good results, the results are mostly under the assumption that the system states can be observed. However, the states are difficult to be observed in practice. In this paper, a novel distributed model predictive control is proposed based on state observer for a kind of linear discrete-time systems where states are not measured. Firstly, an output feedback control law is designed based on Lyapunov function and state observer. And the stability domain is described. Furthermore, the stability domain as a terminal constraint is added into the constraint conditions of the algorithm to make systems stable outside the stability domain. The simulation results show the effectiveness of the proposed method.

Satellite SAR observation of shallow bottom topography of the east Australia Sea

A preliminary account of synthetic aperture radar (SAR) imaging mechanisms of oceanic bottom topographic features and a description of the principles of the information extracted from SAR images and the processing and the analysis technology of SAR images are made. Some results were obtained from researching shallow topography and its bathymetric features of the regions of offshore in the east Australia Sea by ERS-1 SAR images. The preliminary research indicates that these features covered with SAR have never been reported before and some results of them are yielded for the first time in Australia. This information is very valuable in a great number of applications to oceanic engineering, shipping navigation, marine fishery and environment, as well as oceanographic research and development. The paper comes to the conclusion that SAR remote sensing of oceanography and its applications are of great potential.

Boundary Control Problems for 2 ×2 Cooperative Hyperbolic Systems with Infinite Order Operators

In this study, boundary control problems with Neumann conditions for 2 × 2 cooperative hyperbolic systems involving infinite order operators are considered. The existence and uniqueness of the states of these systems are proved, and the formulation of the control problem for different observation functions is discussed.

An Optimization Problem of Boundary Type for Cooperative Hyperbolic Systems Involving Schrodinger Operator

In this paper, we consider cooperative hyperbolic systems involving Schr?dinger operator defined on ?Rn. First we prove the existence and uniqueness of the state for these systems. Then we find the necessary and sufficient conditions of optimal control for such systems of the boundary type. We also find the necessary and sufficient conditions of optimal control for same systems when the observation is on the boundary.

Cooperative output tracking of multi-agent systems under finite time

The cooperative output tracking problem of multi-agent systems in finite time is considered.In order to enable the agents to quickly track and converge to external system within a finite time,a novel distributed output feedback control strategy based on the finite-time state observer is designed.This distributed finite-time observer can not only solve cooperative output tracking problems when the agents can not get external system signal,but also make the systems have a faster convergence and a good robustness.The stability of the system in finite time is proved based on Lyapunov function.Numerical simulations results have been provided to demonstrate the effectiveness of the proposed protocol.

Adaptive Fractional-Order PID Control for VSC-HVDC Systems via Cooperative Beetle Antennae Search with Offshore Wind Integration

Since the voltage source converter based high voltage direct current(VSC-HVDC)systems owns the features of nonlinearity,strong coupling and multivariable,the classical proportional integral(PI)control is hard to obtain content control effect.Hence,a new perturbation observer based fractional-order PID(PoFoPID)control strategy is designed in this paper for(VSC-HVDC)systems with offshore wind integration,which can efficiently boost the robustness and control performance of entire system.Particularly,it employs a fractional-order PID(FoPID)fra-mework for the sake of compensating the perturbation estimate,which dramatically boost the dynamical responds of the closed-loop system,and the cooperative beetle antennae search(CBAS)algorithm is adopted to quickly and effi-ciently search its best control parameters.Besides,CBAS algorithm is able to efficiently escape a local optimum because of a suitable trade-off between global exploration and local exploitation can be realized.At last,comprehensive case studies are carried out,namely,active and reactive power tracking,5-cycle line-line-line-ground(LLLG)fault,and offshore wind farm integration.Simulation results validate superiorities and effectiveness of PoFoPID control in com-parison of that of PID control and feedback linearization sliding-mode control(FLSMC),respectively.

On the Deviation of Cooperative Principle in Business Negotiation

Business negotiation is a delicate art and can be a very trying process of confrontation and concession.Cooperative principle is ac knowledged as a principle of conversation of enhancing the mutual trust and understanding for the purpose of increasing the odd for com munication success.This thesis attempts to highlight the cooperative principle and analyze its inconsistence in business negotiation scenarios.In this paper,whether Cooperative Principle is applicable in business negotiations is the main research question.

基于事件触发机制的多自主水下航行器协同路径跟踪控制

针对考虑外部海洋环境扰动和内部模型不确定性的多自主水下航行器(Autonomous underwater vehicle,AUV),研究其在通信资源受限和机载能量受限下的协同路径跟踪控制问题.首先,针对水声通信信道窄造成的通信资源受限问题,设计一种基于事件触发机制(Event-triggered mechanism,ETM)的协同通信策略;然后,针对模型不确定性和海洋环境扰动问题,设计一种基于事件触发机制的线性扩张状态观测器(Extended state observer,ESO)来逼近水下航行器的未知动力学,并降低了系统采样次数;最后,针对机载能量受限问题,设计一种基于事件触发机制的动力学控制律,在保证控制精度的前提下,降低了执行机构的动作频次,从而节省了能量消耗.应用级联系统稳定性分析方法,分别验证了闭环系统是输入状态稳定的且系统不存在Zeno行为.仿真结果验证了所提基于事件触发机制的多自主水下航行器协同路径跟踪控制方法的有效性.

针对机动目标的三维领从协同制导律

针对多飞行器协同拦截机动目标的实际需求,提出一种三维领从时空协同制导律。在视线方向上,基于齐次度理论和固定时间稳定理论设计一种领从协同制导律,确保从飞行器与领飞行器的相对距离和相对速度在固定时间内趋于一致,并且给出一致性误差收敛时间的上界,实现多飞行器的同时刻拦截。在视线法向上为实现以特定的碰撞角度拦截目标,设计一种固定时间收敛的非奇异终端滑模制导律,实现攻击角度的固定时间收敛,并避免了制导指令奇异引起的控制饱和问题。考虑到目标的机动对制导系统产生的不利影响,引入固定时间扰动观测器对目标加速度进行前馈补偿。运用李雅普诺夫稳定性理论来证明系统的固定时间稳定特性。通过仿真实验验证所设计制导律可以有效控制多飞行器在领从框架下同时打击机动目标,并以期望的终端角度攻击目标。

基于自适应分布式滤波观测器的多智能体系统编队控制

本文考虑了全局指令系统输出信息受到信道扰动情况下线性多智能体系统的编队控制问题.首先,基于协作式输出调节理论框架对线性多智能体系统的编队控制问题进行数学建模.其次,针对受到信道扰动的全局指令系统输出信息,提出了一类基于受扰输出的自适应分布式滤波观测器,在降低网络信息交换量的同时消除扰动的影响.最后,设计了输出反馈确定等价控制律,解决了线性多智能体系统的分布式编队控制问题.给出了数值仿真结果检验控制性能.

通信速率约束下一体化角度协同制导控制方法

针对多飞行器协同拦截过程中的角度协同问题,设计了一种基于量化编码器的分布式一体化协同制导控制律。首先建立多飞行器协同制导与控制数学模型,并基于扩张状态观测器理论,对单个飞行器各状态进行观测。在此基础上考虑各飞行器间单次传输数据的字长、两次传输数据间隔的通信速率约束,采用量化器-编码器-解码器实现限制通信速率情况下的协同一体化制导控制设计。之后,通过严格的理论分析证明了满足强连通图有向通信网络下,多飞行器系统能够达成一致性且收敛到期望的相对视线角,并给出了满足收敛条件的参数选择范围。最后,通过数学仿真校验,验证了所提出的方法在较低的通信速率下能够完成协同。

延安时期中国共产党与美军观察组的气象合作

太平洋战争爆发后,美国政府出于轰炸日本本土、执行“马特霍恩计划”的现实需要,主动寻求与中国共产党进行军事气象合作。1944年6月下旬,美国副总统华莱士来华与国民党协商军事合作问题,气象情报需求成为美军观察组得以赴延安的重要因素之一。中国共产党从统一战线和加快对日作战的实际情况出发,秉持平等友好的态度,对美军观察组表示欢迎。双方曾在建立气象站、搜集和传递信息、培训气象人员等方面进行全面合作,后因美国政府对华政策的转变使双方合作告终。延安时期中国共产党与美军观察组的气象合作不仅有助于美军对日轰炸行动,也为后来中国共产党独立自主地开展气象工作积累了技术经验。总结这一时期双方气象合作的历史经验,对于新时代更好地推进中美关系良性发展具有一定的借鉴意义。

多站联合观测非合作目标的定位批号关联算法

在多站联合对非合作多目标进行定位场景中,提出了一种批号关联算法。该方法利用模糊数学理论描述已关联集和待关联量测中方位信息、连续谱特征信息和线谱特征信息之间的模糊隶属度,构建综合模糊关系矩阵进行二维关联,通过设置隶属度门限消除低隶属度关联的影响。仿真结果表明,所提算法克服了传统算法在目标增多关联成功率下降的问题,在一定的漏报虚警时关联结果召回率可达到0.8以上,关联结果精度也保持在较高水平。仿真结果及试验数据均验证了该方法在复杂水下环境中较好的目标关联定位性能。

协作机械臂碰撞环境下的安全控制

针对人机协作过程中机械臂末端与操作者之间可能存在物理碰撞的问题,本文提出一种基于自适应导纳和滑模控制的机械臂安全控制方法.首先,采用基于广义动量的干扰观测器估计机械臂各关节和末端执行器上的干扰力.然后,设计一个双环控制结构,内环是基于干扰观测的双幂次趋近律滑模轨迹跟踪控制器,用以克服外界干扰的影响,达到期望的轨迹跟踪精度;外环是自适应导纳控制器,依据碰撞外力的大小和方向更新期望轨迹,以保证机械臂碰撞发生时的柔顺性和碰撞解除后迅速恢复工作状态的能力.最后,对所提算法进行仿真和实验验证.实验结果表明,协作机械臂碰撞环境下的安全控制算法能保证人机协作的安全性和机械臂工作的连续性,满足人机协作过程中的工作需求.

对地观测卫星编队协同容错姿轨耦合控制

面向对地观测场景下卫星编队的姿轨耦合特性和完全失效故障,提出了基于空间构型重构的协同容错控制方法。首先,根据对地观测的任务需求,分别建立了无故障情况下的卫星编队构型,以及故障发生后将故障卫星移出编队的构型重构方案,包括拓扑网络重构、卫星编号更新和编队构型重构算法;其次,根据上述构型,考虑外部干扰和姿态轨道耦合特性,设计了基于非奇异终端滑模控制的分布式控制律,使得编队在有限时间内稳定,即在故障发生前后卫星编队都可以实现对观测区域的协同覆盖;最后,分别通过数值仿真和实验验证表明了所提方法的有效性。

一种基于扰动补偿的机弹协同LOS主动防御制导律

随着无人技术和军事科技发展,无人近距空战引起了世界军事强国的广泛关注。面临高速大机动能力来袭导弹的威胁,传统的抛洒箔条或释放热焰弹等被动防御措施无法确保目标飞行器安全逃逸,通过发射拦截弹协同目标飞行器机动实施的主动防御是一种可行的方法。由于来袭导弹机动能力较强且加速度信息未知,是目标飞行器-拦截弹制导律协同设计的难点。提出一种基于扰动补偿的LOS主动防御拦截制导律,通过设计一种非线性扰动观测器来估计来袭弹产生的机动的影响,并在机弹协同LOS主动防御制导律设计中补偿。通过仿真算例验证了所提方法能够有效拦截具有未知机动能力的来袭导弹,为研究三体攻防问题提供了一定的参考。

增强探测信息可观测性的主动防御滑模协同突防制导律

针对敌方来袭拦截弹制导策略未知的主动防御协同突防场景,考虑目标弹-防御弹单向和双向协同配合模式,采用滑模控制方法提出了兼顾拦截弹探测信息可观测性和防御弹反拦截精度的协同突防制导律。构建了融合空间探测构型需求和拦截成功必要条件的滑模面,分别应用双幂次趋近律和带状态反馈的指数型趋近律,推导了目标弹-防御弹的单/双向协同制导律。相较于单向协同,双向协同通过引入加速度代价函数,应用最优化方法优化了协同突防制导律,目标弹通过协作机动帮助防御弹降低打击来袭拦截弹的过载需求。仿真结果表明,协同滑模突防制导律可确保目标弹和防御弹达到期望的空间探测构型,并能够精准地打击来袭拦截弹。

基于观测重构的多智能体强化学习方法

共同知识是多智能体系统内众所周知的知识集。如何充分利用共同知识进行策略学习,是多智能体独立学习系统中的一个挑战性问题。针对这一问题,围绕共同知识提取和独立学习网络设计,提出了一种基于观测重构的多智能体强化学习方法IPPO-CKOR。首先,对智能体的观测信息进行共同知识特征的计算与融合,得到融合共同知识特征的观测信息;其次,采用基于共同知识的智能体选择算法,选择关系密切的智能体,并使用重构特征生成机制构建它们的特征信息,其与融合共同知识特征的观测信息组成重构观测信息,用于智能体策略的学习与执行;最后,设计了一个基于观测重构的独立学习网络,使用多头自注意力机制对重构观测信息进行处理,使用一维卷积和GRU层处理观测信息序列,使得智能体能够从观测信息序列中提取出更有效的特征,有效缓解了环境非平稳与部分可观测问题带来的影响。实验结果表明,相较于现有典型的采用独立学习的多智能体强化学习方法,所提方法在性能上有显著提升。