点S平面运动机械手的位置精度可靠度

为开发大臂回转中心在原点，手部(简化为点S)做平面运动且有位置精度可靠度要求的关节式机器人时实控制系统，用矢量算法取代D—H矩阵变换导出了该机器人位置和关节变量计算式，提出了位置精度可靠度概念，探讨了用概率设计方程解决其可靠性设计问题，用泰勒级数估计了有关函数离差系数，通过实例说明了该方法的应用。     

喷涂机器人关节的PID自适应模型

针对喷涂机器人各关节传递函数的时变性,建立了一种比例积分微分(PID)控制器参数自整定模型.首先,对喷涂机器人进行动力学分析,应用数值法简化关节动力学方程,建立各关节的传递函数;在此基础上,通过试验,设计在不同位置的PID控制器,获取相应的PID参数,并应用最小二乘法建立PID参数与关节转角位置的数学模型;最终利用该模型设计了下一时刻关节的PID控制器,并进行了仿真试验.结果表明,基于该模型设计的PID控制器响应速度快,机器人的位置精度小于±0.1mm,基本可满足喷涂作业要求.     

一种新型机器人关节位置传感器的研制

为了满足机器人小型化、轻型化的要求,利用磁钢霍尔元件体积小、质量轻和非接触的特点,将其作为机器人关节和电机角度的测量单元,并采取特殊的机械结构,研制了一种新型的关节位置传感器。传感器具有2个测量单元,能够同时测量关节和电机的角度,关节位置测量单元可以用较高精度的电机位置测量单元实现动态标定,标定试验得到传感器精度为±3.08%,重复精度为±1.95%。传感器的2个测量电路安装在同一印刷电路板上,共用电源和A/D电路,具有较高的集成度和可靠性。     

平面关节型装配机器人的计算机控制

介绍了一种平面关节型机器人的计算机系统的组织结构、示教系统、伺服系统以及系统软件。该系统结构简单、价格便宜。脉冲分配电路和读位置电路所用硬件最少。合理的系统设计确保了机器人高的位置精度。     

基于机器人操作系统的液压机器人自主导航系统设计与实现

在机器人两轮差速运动模型分析的基础上,根据运动模型的航迹演算公式可实时计算机器人轨迹姿态。基于机器人操作系统架构平台设计了机器人本体、机器人底座、驱动液压马达、导向轮、激光雷达等7个关节和连接的结构模型。各机器人关节坐标系变换关系经过Tf实时发布,用于计算机器人位置坐标信息。针对液压机器人没有配备编码器和视觉系统的不足,系统采用2D平面激光里程计模型(RF2O),通过建立连续激光扫描点对距离的流约束方程获得机器人平面运动估计,进而得出激光雷达的速度和机器人实际运行轨迹。设计了自主导航软件系统,实现了导航地图构建、定点任务导航和多机器人管理等功能,并对机器人定位导航精度进行了测试,分析对比多次指定位置和导航位置的数据差异,结果表明机器人导航定位精度达到设计要求。     

多关节型机器人的控制运动学及其结构参数的综合

本文用回转变换张量法,建立了供电子计算机对工业机器人进行轨迹或速度控制的数学模型.同时,还建立了多关节型机器人结构参数的综合设计公式.在已知机器人手末所要求的位置座标和被夹持工件姿态时,该公式可求出机器人的所有结构参数.     

利用姿态约束的并联机器人运动学标定方法

为了提高并联机器人运动精度,提出了一种利用姿态约束的运动学标定方法.借助一个双轴倾角仪,建立了机器人末端2个姿态角恒定约束,根据这种约束构造了相应的辨识模型和标定算法.标定算法得益于倾角仪重复精度和分辨率高于位置精度的特点,不受其位置精度和量程的限制,同时可避免施加机械约束给并联机器人主动关节带来特殊要求.仿真计算表明,在杆长测量精度为2μm、倾角仪重复精度为0.001°的条件下,经过标定后并联机器人的位置精度可达0.1 mm,姿态精度可达0.01°.     

冶炼机器人位姿标定及运行可靠性

对冶炼用CS-1双臂工业机器人现场使用中的位姿标定及运行可靠性进行了研究．提出了一种简便有效的现场标定计算模型和标定方法对机器人进行位姿标定,由标定变换矩阵补偿同一测点的实际值和计算值的误差,可同时减少机器人定位误差和由臂杆几何参数偏差所引起的运动误差,显著提高需进行连续路径控制的机器人的现场定位精度和位置跟踪精度．此外,提出了用增加机器人现有硬件的冗余功能和设置敏感器件的替代功能以提高机器人现场运行可靠性的方法．实践证明,该方法能提高恶劣环境下易失效部件的可靠度,进而提高机器人的整机使用性能     

基于偏置补偿的6自由度腕部偏置机器人逆解算法

串联6自由度腕部偏置机器人一般没有实用的封闭形式位置逆解.根据几何特征分析,以对应的腕部无偏置机器人的封闭解为基础,通过对腕部偏置量的平移补偿和对手腕位置点坐标的迭代修正,得到了腕部偏置机器人位置逆解的数值解.算法保证了末端姿态的正确性.根据末端位置精度要求控制迭代次数,可以得到任意精度的位置逆解.逆解过程中各关节变量的计算采用腕部无偏置机器人的封闭解,使得程序具有通用性.大量的数据试验表明,该算法可以满足实时控制要求.     

基于单维拉线测量系统的码垛机器人定位误差分析及运动学标定

以四自由度码垛机器人为研究对象,基于单维拉线测量系统对该机器人的运动学标定方法进行了研究.采用环路增量法构造了码垛机器人平行四连杆的误差模型,并建立了带关节变量比例系数的运动学误差模型,从而对关节传动误差进行补偿.通过对影响机器人末端位置精度的几何误差参数进行敏感性分析,将几何误差源简化为11项,可有效提高辨识效率.结合单维拉线测量系统的特点,建立了末端运动误差与几何误差源的映射关系,进而提出了一种基于距离测量的参数辨识模型.通过计算机仿真和标定试验对该方法的有效性进行了验证.试验结果表明,标定后码垛机器人位置误差3?值由11.73,mm减小至1.79,mm,运动精度提升84.7%,.     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the     

Call for Papers

<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with     

Journal of Donghua University ( English Edition) Contents of Volume 31

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