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。     

多移动机器人编队运动中的避障控制

多移动机器人的编队运动是一类典型的多机器人协调问题.针对多移动机器人在编队运动中的避障问题,提出了基于监控模式的控制系统框架,解决了避障过程中可能出现的掉队问题.仿真实验验证了控制方法和控制系统的可行性.     

基于粒子滤波的微小型移动机器人红外定位研究

对微小型移动机器人之间的协作定位问题进行了研究.根据微小型机器人的结构特点,建立了它们之间的红外定位模型.在红外定位的基础上,将粒子滤波算法应用于微小型移动机器人的状态估计中.结合红外传感器信息更新各时刻机器人位姿信息的粒子集,并利用粒子集逼近机器人当前时刻的位姿状态.通过实验和误差分析,对所建立的基于粒子滤波的红外定位方法的可行性进行了验证.     

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。     

基于视觉里程计的移动机器人三维场景重构

研究移动机器人在不依赖GPS环境下的三维场景重构方法.在基于双目视觉的实时位姿估计中,使用基于最大团的内点选取方法对RANSAC算法进行优化,通过鲁棒的运动估计算法求解机器人的三维位姿.基于自主研发的全景三维激光系统来实现室内场景的三维点云数据采集,同时利用视觉里程计提供的移动机器人可靠位姿来完成多视点下的三维点云数据融合,从而保证了大范围三维场景重构的有效实现.利用SmartROB移动机器人平台在办公大厦的室内、走廊及大厅等多种环境进行了实验验证,实验结果表明本文所提方法的有效性和实用性.     

多假设跟踪的移动机器人SLAM算法

针对基于视觉定位的移动机器人自主定位过程中容易产生多种候选位姿.提出一种基于多假设跟踪的同时定位和地图创建方法.该方法通过提取图像SIFT特征进行视觉量测,修正里程计累计误差,再利用多假设跟踪方法获得当前时刻的最优位姿,实时产生环境的栅格地图,并且随着机器人的位姿变化实时更新.研究结果表明:此算法不仅能够较好地创建环境地图,而且能够有效解决机器人"绑架"问题,提高自主定位精度.     

多移动机器人保持队形路径规划

将多移动机器人的运动控制和路径规划有机结合,提出了多移动机器人的队形模型和保持队形的定义.在此基础上,以基于行为的导航算法为基础,将机器人队列的运动过程划分为正常运动、避障和恢复队形3个阶段.在避障阶段,引入虚拟机器人使队形保持部分完整;当队形被严重打乱时,规划机器人的局部目标位姿使队列快速恢复队形.仿真实验表明,该控制方法不仅使多移动机器人安全避障,而且队形保持较完好.     

多自由度机器人位姿稳定性控制方法研究

对于多自由度机器人位姿控制方法来说,机器人位姿稳定性受到各种因素的干扰,容易发生位姿失稳现象,为此,提出一种新的方法来解决此问题.采用扩展卡尔曼滤波算法实现多自由度机器人各个传感器数据的有效融合,获取多方位机器人位姿数据;通过传感器信号处理去除机器人位姿测量噪声,使用自适应扩展技术实现机器人参量与姿态角校正信息融合,通过反演积分项自适应调节姿态参量并弥补稳态误差,实现机器人的位姿稳定控制.仿真实验结果表明,该控制方法能够准确实现多自由度机器人位姿稳定性控制,即使引入扰动机制仍然不会出现控制失衡,具有较好的稳态控制效果.     

基于行为优先与任务协调的多移动机器人遥操作

针对单个操作者对多个移动机器人遥操作的困难,提出了基于行为优先和任务协调的多机器人遥操作方法. 通过引入机器人局部自主的概念,运用行为优先决策与任务协调模块使操作者和机器人共享运动控制. 建立了多机器人系统遥操作体系结构,设计了多通道人机交互接口界面. 室外实验表明,提出的方法可以实现人和机器智能的合理分配. 运用该方法,单个操作者可完成对多个移动机器人的遥操作.     

基于主动信标和航位推测法的多机器人位置最优估计

针对一种新的多机器人交替定位方式,研究基于主动信标和航位推测法的多机器人位置估计算法. 指定多机器人中的3个保持静止作为信标机器人(不一定始终是同样3个机器人),其它机器人作为移动机器人. 通过超声波测距得到移动机器人与3个信标机器人的距离,并通过IEKF(iterated EKF)算法将距离信息和移动机器人的航位推测信息相融合,实现移动机器人位置的最佳估计. 轮流交换机器人作为主动信标的角色,即可实现多机器人的位置估计. 实验验证结果表明,移动机器人的位置估计误差在±10 mm之内;该方法有效,且不需要在环境中设置固定信标,可应用于未知环境.     

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…     

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.     

Tracking data management using topology of moving object database system for moving object constrained trajectory in LBS application

Advances in wireless technologies and positioning technologies and spread of wireless devices, an interest in LBS (Location Based Service) is arising. To provide location based service, tracking data should have been stored in moving object database management system (called MODBMS) with proper policies and managed efficiently. So the methods which acquire the location information at regular time intervals then, store and manage have been studied. In this paper, we suggest tracking data management techniques using topology that is corresponding to the moving path of moving object. In our techniques, we update the MODBMS when moving object arrived at a street intersection or a curved road which is represented as the node in topology and predict the location at past and future with attribute of topology and linear function. In this technique, location data that are corresponding to the node in topology are stored, thus reduce the number of update and amount of data. Also in case predicting the location,because topology are used as well as existing location information, accuracy for prediction is increased than applying linear function or spline function.