上下料机器人关节速度规划

新兴的高新技术产业和智能化产业推动了上下料机器人的快速发展,但是其运动的平稳性限制着进一步的推广与应用.设计了一种4R上下料机器人.首先建立梯形、7段S曲线加减速控制算法,通过分析这两种算法对机器人运动平稳性的影响,提出了一种新型的S形加减速控制算法.利用ADAMS对三种算法进行仿真分析,结果表明新型的S形加减速控制算法在提高4R上下料机器人的运动平稳性方面更具优势并为4R上下料机器人后续的运动控制分析和优化奠定了基础.     

基于ADAMS的装车机器人运动分析

为了提高装车机器人的运动平稳性,采用UG和ADAMS软件联合仿真的方式,对装车机器人进行了运动分析。首先利用UG对机器人进行三维建模,并利用ADAMS建立机器人的虚拟样机模型。然后建立梯形曲线、S型曲线的速度模型,仿真分析这两种速度曲线对机器人运行稳定性的影响。针对S型曲线中加速段和减速段加加速度不连续,提出了一种三次S曲线加减速控制算法。仿真结果表明,三次S曲线加减速控制算法能够保证加速度和加加速度的平稳变化,避免产生大的冲击,使机器人运动更加平稳,为机器人的运动控制及优化提供了参考。     

三次均匀B样条在工业机器人轨迹规划中的应用研究

工业机器人在加工不规则工件时用直线和圆弧轨迹逼近工件外形的方法不能满足加工要求。为了解决这一问题,研究三次均匀B样条曲线拟合方法在工业机器人轨迹规划算法中的应用,目的是使机器人末端以三次B样条的曲线轨迹通工件上各加工点。首先,分析三次均匀B样条曲线的特性,给出了三次均匀B样条曲线的表达式。然后,在增加曲线自由端点条件后、使用追赶算法快速反算出控制点;使用预估校正的方法对速度进行规划,使机器人末端速度以梯形加减速规律变化。最后,以国产某型号工业机器人为本体,对所提算法进行仿真验证,给出了该型机器人的关节连杆模型和D-H参数。仿真效果良好,证明该算法具有可行性。     

基于粒子群优化的改进四次S型加减速控制算法

针对基于传统三次S型加减速算法在数控机床起止端加加速度不连续,存在柔性冲击,以及传统四次S型加减速算法模型繁复,时间复杂度高的问题,设计加加速度曲线在加速区间、减速区间的开始和结束阶段连续不断变化,提高了速度曲线变化的平滑性,减低了工件加工运行时间。同时,提出一种基于粒子群算法的速度规划方法,根据加减速控制模型构建其适应度函数,继而得到加减速规划所需的所有参数。最后通过MATLAB对所提算法进行仿真实验。结果表明：所提算法能有效降低系统的柔性冲击,并提高加工精度和运行效率。     

拱泥机器人避障运动分析及其系统仿真

路径规划问题是拱泥机器人研究中的一项关键技术。在概述拱泥机器人的基本构成,分析其规划策略的基础上,提出拱泥机器人避障运动控制器路径规划算法,并通过仿真实验得以验证,实现了局部规划与全局导航目标的有机结合。基于该规划策略及其算法,设计集数据接口、硬件接口、数学运算接口和图形化接口为一体的避障运动仿真系统。结果表明,该规划策略对拱泥机器人在未知泥土环境下实现动作稳定、轨迹平滑的避障运动具有良好的效果。     

基于改进TEB算法的阿克曼机器人运动规划系统

TEB(timed elastic band)算法通过修饰全局路径规划生成的初始轨迹来优化机器人轨迹,得到一条满足机器人运动学动力学约束,避开障碍物,时间较优的轨迹。加速度的变化率过大会使机器人底盘电机输出的力矩突变引起机器人受到冲击震荡,加加速度的约束可使加速度的变化率限定在一个合理的范围,在TEB方法中缺少加加速度约束的基础上,对原始TEB算法进行改进,在轨迹优化过程中构建了具体的加加速度的约束,并在Stage仿真平台对改进TEB算法进行了仿真和在真实的阿克曼机器人上进行了实现,实验结果表明:得到的轨迹满足运动学、动力学,避开障碍物的要求而且平滑,真实机器人运动平顺。可见,改进的TEB算法适用于阿克曼机器人,规划的轨迹效果较好。     

移动机器人运动规划研究综述

机器人运动规划是移动机器人导航的核心技术之一。40多年来，运动规划技术发展迅速，涌现出了许多规划算法，但因为环境描述方式差异巨大，技术差别大，实验比较难度较大。在总结机器人发展史上具有典型意义的规划算法的基础上，提出了路径规划算法的评价标准和形式化描述方式，介绍了每种算法的原理或技术，从搜索策略和环境建模的角度将它们分为四大类，分别是基于自由空间几何构造的规划算法、前向图搜索算法、基于随机采样的运动规划算法以及智能化规划算法，并按照提出的标准比较它们的性能。     

焊接柔性加工单元用数控变位机的研制

依据现有进口弧焊机器人的技术特点和工作要求 ,研制了 1台与之配套的数控焊接变位机 ,该机工作台可进行回转和倾斜两个运动 ,可使工件置于最佳的位置进行焊接 .这两个运动均采用交流伺服电机驱动、谐波减速器减速和工控机加模糊控制的方法进行控制 ,运动速度可在大范围内均匀调节 ,能满足不同焊接速度的需求 .     

一种新型柔性加减速算法

针对传统的直线加减速和指数加减速算法在进给过程中存在柔性冲击的问题，提出了一种适用于高速进给的新型柔性加减速算法，采用三角函数构造加减速曲线。对这种加减速模式进行了详细的分析和探讨，并提供了一种新型数控进给系统设计方法。     

多功能移动机器人分层路径规划研究

现有移动机器人规划算法生成轨迹目标单一,无法满足多样化的任务需求,为此,提出一种多指标维度反馈的路径规划策略。基于强化学习在线决策机制,寻求多条抵达目标的无碰撞路径;进而根据路径性能特征建立价值评估体系,动态更新机器人运动节点间的动作代价值,并且在不同权重配比下进行了仿真测试。结果表明：该算法能根据需求针对性提高全局路径相关性能,并结合全局路径信息,反馈控制局部运动决策,从而使得移动机器人能够在相同环境中解算出不同满足期望的运动决策。     

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).     

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.     

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.