一种基于局部感知的多机器人编队控制方法

针对未知环境下多机器人难以实现灵活、稳定的编队控制的情况,在分析领队-跟随法、基于行为方法以及虚拟结构法的编队控制方法基础上,提出了一种模拟人类社会中方队形成与变化的思想,将其应用在多机器人的编队中,进行多机器人的编队控制.机器人存储不同编队队形的相对位置信息,通过领航者发布队形控制信息,跟随者查找并匹配预先存储的队形...     

基于通信的多移动机器人编队控制系统

论述了一类通用的经过通信信道进行协调的多移动机器人编队控制系统.在分别获取自身位姿信息的前提下,各个机器人通过通信信道交换和共享同组成员的位姿信息,然后通过计算得到各机器人之间的相对位姿,进而完成编队协调任务.利用此技术,可实现一种不受环境限制的多机器人编队,其特点在于编队的完成主要依赖于通信系统,不论编队中各机器人是否能够彼此感知,编队都能进行,从而提高了多机器人编队对环境的适应性.采用闭环l-ψ编队控制算法验证此设计方法的有效性,在三台移动机器人上进行了实验,实验结果证明了该方案的可行性.     

未知环境中基于观察者的多机器人编队控制方法

结合领导-跟随法和VFH+ 避障法,提出一种基于观察者的多机器人编队控制方法,并利用Player/Stage机器人仿真平台,对编队控制方法进行了仿真实验.结果表明,编队控制方法可有效地将一组移动机器人以一定队形无碰地到达指定目的地.基于Player/Stage机器人仿真平台的特性,编队控制方法完全可以用于实际机器人上.     

基于仿生鱼群优化方法的非完整机器人队形控制(英文)

利用人工鱼群优化(AFSO)方法研究了多机器人的队形控制问题。机器人编队可视为寻迹问题,而编队寻迹是不断减小机器人与其期望编队位置之间的平移和角度误差的优化过程。每一个机器人的控制指令可看做是人工鱼群,通过一系列的控制实现期望队形。队形控制策略中包含机器人间的冲突规避行为。利用Matlab中的多机器人仿真器MRsim工具进行了仿真,结果表明,提出的方法具有很高的有效性和效率,适用于各种形式的队形,可以被广泛应用在没有精确系统模型的无线传感器网络中。     

基于仿生鱼群优化方法的机器人队形控制

本文利用人工鱼群优化（AFSO）方法研究了多机器人的队形控制问题。机器人编队可视为寻迹问题,而编队寻迹是不断减小机器人与其期望编队位置之间的平移和角度误差的优化过程。每一个机器人的控制指令可看做是人工鱼群,通过一系列的控制实现期望队形。队形控制策略中包含机器人间的冲突规避行为。本文利用Matlab中的多机器人仿真器MRsim工具进行了仿真,结果表明本文提出的方法具有很高的有效性和效率,适用于各种形式的队形,可以被广泛应用在没有精确系统模型的无线传感器网络中。     

基于干扰观测器的多移动机器人编队鲁棒控制

针对多移动机器人存在模型参数不确定性和外部扰动的编队控制问题,提出了一种多移动机器人编队的鲁棒控制方法。在运动学层面依据领航机器人和跟随机器人位姿的偏差,建立领航机器人和跟随机器人的编队误差动态模型,在此基础上为跟随机器人设计镇定编队误差的辅助速度控制器。以辅助速度控制器的输出作为跟随机器人动力学模型的速度给定信号,并在动力学层面设计基于干扰观测器的自适应滑模控制算法,从而改善普通滑模控制中抖振突出的问题,保证编队控制的稳定性和鲁棒性。对编队控制系统进行仿真验证,结果表明了所提控制方法的有效性。     

基于领航跟随法和星系动力学的多机器人编队控制

针对机器人常规编队控制方法编队精度低、机器人易掉队,且当队形进行大角度变换时跟随者不能快速适应的问题,提出了一种基于领航跟随和星系动力学(LF-GD)机器人编队控制方法.该方法结合了领航跟随法控制简单、编队快速和星系动力学法编队稳定和动态均衡的优点.实现了机器人快速编队和动态避障的性能要求,避免了队形大角度变换时机器人相互之间的碰撞和掉队问题,提高了整个编队系统的智能性和环境适应性.通过仿真验证了该方法的可行性和有效性.     

多智能体编队避障算法研究

利用势函数方法,研究了多智能体在障碍物环境下的追击编队控制.为解决单个智能体在势场中存在局部极小点与动态性能不好问题,引入速度势场建立新的势场函数.并研究了多智能体在不同环境下的编队控制,其中包括无障碍物环境,静态障碍物环境,以及静态障碍物和动态障碍物并存的复杂环境.通过选择与目标,障碍物和编队队形相关的势场函数,提出一种新的分布式编队避障控制算法.仿真结果表明所提算法能有效地解决多智能体编队避障问题.     

基于竞标机制的多移动机器人实时编队控制

研究了整体时间最优的多移动机器人实时编队控制问题。由于在多机器人编队围捕等一些任务中,存在任务时间或通信范围有限等约束,提出了基于竞标机制的时间最优控制策略。针对编队过程中机器人可能发生故障等问题,在实时编队控制策略中设置了监督机制,以保证任意时刻编队队形的完整。设计了与竞标和监督机制相适应的机器人编队及运动行为,使得移动机器人的运动时间最少。通过编队形成及编队改变等一系列实时编队仿真实验,结果表明:本文提出的编队控制策略灵活可行,且能满足编队控制中实时性的要求。     

基于相邻矩阵的多机器人编队容错控制

针对基于leader-follower模式的多机器人编队运动中可能出现的机械故障和网络故障,提出了一种基于相邻矩阵的容错控制方法,利用相邻矩阵表示编队中多机器人的相互位置关系,一旦在编队运动过程中出现故障,则利用调整队形搜索算法找到需要进行队形调整的机器人编号,根据相邻矩阵更新算法,这些编号所代表的机器人的相邻关系在相邻矩阵中得以调整,新的理想编队所对应的相邻矩阵产生,编队队形就可以依赖相邻矩阵重新得以恢复。从而实现多机器人编队的容错控制,仿真实验证明了该方案的有效性和可行性。     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3～4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰～ -7.8‰, PDB) and matrix dolomites (-6.6‰～ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084～0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078～0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.     

A computer generator for randomly layered structures

AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…     

An Index mechanism for multi-scale view in spatial databases

There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.     

海南岛地体及其毗邻陆缘晚中生代—新生代古地磁研究和构造演化

本文叙述了对海南岛及其毗邻大陆边缘白垩纪到第四纪地层岩石进行古地磁研究的全部工作过程。通过分析岩石中剩余磁矢量的磁偏角及磁倾角的变化,提出海南岛白垩纪以来经历的构造演化模式如下:早期伴随顺时针旋转而向南迁移,后期伴随逆时针转动并向北运移。联系该地区及邻区的地质、地球物理资料,对海南岛上述的构造地体运动提出以下认识:北部湾内早期有一拉张作用,主要是该作用使湾内地壳显著伸长减薄,形成北部湾盆地。从而导致了海南岛的早期构造运动,而海南岛后期的构造运动则主要是受南海海底扩张的影响。海南地体运动规律的阐明对于了解北部湾油气盆地的形成演化有重要的理论和实际意义。     

Exciton Seebeck in Molecular Systems

Various applications relevant to the exciton dynamics,such as the organic solar cell,the large-area organic light-emitting diodes and the thermoelectricity,are operating under temperature gradient.The potential abnormal behavior of the exicton dynamics driven by the temperature difference may affect the efficiency and performance of the corresponding devices.In the above situations,the exciton dynamics under temperature difference is mixed with     

Achieving Unusual States of Matter Under High Pressure

The elongation method,originally proposed by Imamura was further developed for many years in our group.As a method towards O(N)with high efficiency and high accuracy for any dimensional systems.This treatment designed for one-dimensional(ID)polymers is now available for three-dimensional(3D)systems,but geometry optimization is now possible only for 1D-systems.As an approach toward post-Hartree-Fock,it was also extended to     

《Chinese Science Bulletin》SUBJECT INDEX TO VOLUME 59(2014)

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An on-line scaling method for improving scalability of a database cluster

The explosive growth of the Internet and database applications has driven database to be more scalable and available, and able to support on-line scaling without interrupting service. To support more client's queries without downtime and degrading the response time, more nodes have to be scaled up while the database is running. This paper presents the overview of scalable and available database that satisfies the above characteristics. And we propose a novel on-line scaling method. Our method improves the existing on-line scaling method for fast response time and higher throughputs. Our proposed method reduces unnecessary network use, i.e. , we decrease the number of data copy by reusing the backup data. Also, our on-line scaling operation can be processed parallel by selecting adequate nodes as new node. Our performance study shows that our method results in significant reduction in data copy time.     

An improved R-tree based on childnode''s probability

R-Tree is a good structure for spatial searching. But in this indexing structure,either the sequence of nodes in the same level or sequence of traveling these nodes when queries are made is random. Since the possibility that the object appears in different MBR which have the same parents node is different, if we make the subnode who has the most possibility be traveled first, the time cost will be decreased in most of the cases. In some case, the possibility of a point belong to a rectangle will shows direct proportion with the size of the rectangle. But this conclusion is based on an assumption that the objects are symmetrically distributing in the area and this assumption is not always coming into existence. Now we found a more direct parameter to scale the possibility and made a little change on the structure of R-tree, to increase the possibility of founding the satisfying answer in the front sub trees. We names this structure probability based arranged R-tree (PBAR-tree).     

Integrating GIS Web services based on mediating architecture

The geographic information service is enabled by the advancements in general Web service technology and the focused efforts of the OGC in defining XML-based Web GIS service. Based on these models, this paper addresses the issue of services chaining,the process of combining or pipelining results from several interoperable GIS Web Services to create a customized solution. This paper presents a mediated chaining architecture in which a specific service takes responsibility for performing the process that describes a service chain. We designed the Spatial Information Process Language (SIPL) for dynamic modeling and describing the service chain, also a prototype of the Spatial Information Process Execution Engine (SIPEE) is implemented for executing processes written in SIPL. Discussion of measures to improve the functionality and performance of such system will be included.