基于距离误差的机器人运动学标定

基于机器人的DH运动学模型,建立了机器人各坐标系间的齐次变换误差模型.为避免因轴线的微小偏差引起连杆距离的较大变动,利用修正的DH运动学模型,建立了平行关节的齐次变换误差模型;用空间两点间的距离误差衡量机器人的绝对定位精度,并结合所建立的齐次变换误差模型,推导了基于距离误差的运动学标定模型,距离误差的引入避免了坐标系的...     

平面二自由度并联机器人运动学参数的快速估计方法

以闭链约束方程为基础,建立了平面二自由度并联机器人的运动学误差模型,并进一步提出了基于两步迭代的运动学参数校准方法.通过先估计被动关节角度误差和运动学参数误差,实现了对并联机器人运动学参数的估计.该方法通过对并联机器人12个运动学参数的校准仿真实验,对所提参数估计方法进行了验证,得到了准确的参数估计结果.     

基于改进模拟退火算法的工业机器人绝对定位精度提高

工业机器人在抛光大口径光学元件时由于其较低的绝对定位精度,使得加工元件较难达到较高的面形精度．本文提出一种通过考虑测量坐标系与机器人基坐标系之间的转换误差、机器人的运动学误差以及机器人法兰端到工具坐标系的测量误差等多误差源构建工业机器人综合误差模型的校准方法．通过仿真实验与PSO、AFSA、SA算法进行对比,证明改进后的Be-SA算法在辨识误差参数时具有更快的收敛速度和更高的精度．实验结果表明通过Be-SA算法辨识后的KUKAKR120R3900的平均绝对定位误差由2.497 mm降低为0.321 mm,最大绝对定位精度由3.358 mm降低为0.961 mm,构建的综合误差模型在辨识运动学误差参数时具有良好的适用性,改进后的Be-SA算法能有效提高机器人的绝对定位精度,对于磨抛大口径光学元件的性能提升具有重要参考价值．     

喷印机器人工具坐标系标定

提出一种利用激光跟踪仪标定机器人工具坐标系的方法。利用激光跟踪仪确定机器人的基坐标系,将机器人基坐标系与激光跟踪仪的测量坐标系统一。通过机器人运动学方程获得机器人末端连杆坐标系相对基坐标系的变换关系,利用激光跟踪仪测量拟合得到机器人工具坐标系,利用坐标变换初步确定机器人工具参数。通过机器人单轴旋转运动对工具坐标系原点进行修正,最终确定工具参数。最后通过机器人重定位运动对误差进行计算。实验结果表明,修正后x,y,z坐标的RMS(root mean square,均方根)误差分别为0.127 1,0.141 3和0.117 4mm,精度是修正前的2.5倍。     

基于Matlab的ER50A型拆捆机器人运动特性分析

以ER50A机器人为研究对象,通过MDH参数法建立机器人连杆坐标系,根据连杆坐标系之间的矩阵变换关系推导出机器人正逆运动学方程,通过五次多项式插值算法对机器人末端进行点到点运动轨迹规划.在Matlab中利用Robotics工具箱对机器人进行建模和正逆运动学仿真分析,根据蒙特卡洛算法对机器人工作空间进行模拟,通过轨迹仿真...     

六自由度串联工业机器人运动学标定与实验研究

为了提高机器人的绝对定位精度,以RB08型六自由度串联工业机器人为研究对象,在修正Denavit-Hartenberg(D-H)运动学理论的基础上加入减速比和耦合系数建立新的运动学模型,通过机器人末端法兰盘中心的空间位置误差推导出机器人参数误差模型;运用Levenberg-Marquardt算法辨识出误差模型中的误差参数并补偿至机器人控制系统,利用激光跟踪仪设计标定实验,验证标定算法的可行性和准确性。结果表明,标定后机器人末端工具中心点的平均位置准确度提高了80.2%,平均距离准确度提高了74.55%。     

五自由度搬运机器人系统设计与运动学分析

设计了一种用于冲压生产线上下料操作的新型五自由度搬运机器人.首先,结合冲压生产线的应用需求设计了机器人的机械结构,并进一步构建了其控制系统;然后,对机器人运动学进行分析,建立机器人连杆坐标系,利用D-H法描述机器人正向运动学模型,并求解机器人逆运动学;最后,对机器人工作空间和运动精度进行描述,将工作空间分别投影到xy,xz,yz三个平面得到其具体参数,利用雅可比矩阵求解各关节最大容许误差,对机器人的参数设计和轨迹规划具有指导意义.     

UR5机器人运动学及奇异性分析

为了解决UR5机器人用户建立的机器人坐标系与厂家建立的机器人坐标系不一致,机器人内部有关力、角速度、角加速度等数据信息难以被直接使用的问题,在分析UR5机器人结构特点的基础上,建立与厂家数据匹配的坐标系。采用D-H参数法建立UR5机器人的运动学方程,描述机器人各杆件的相对位姿关系,依据UR5机器人满足Pieper准则的结构特性,采用分离变量法求取UR5机器人的运动学反解,并利用微分变换法完成UR5机器人奇异位形分析,奇异性分析与仿真结果表明了UR5机器人位置奇异时各关节变量之间的关系。使用MATLAB软件编写运动学程序,并利用机器人系统对程序进行实验室测试与工程实践验证,MATLAB运动学程序实验结果与UR5系统内部数据一致,验证了运动学分析的正确性。研究结果对进一步开展UR5机器人连续轨迹规划研究具有参考价值。     

基于主动视觉的机器人末端姿态测量

采用平面校准形及移动摄像机到不同形位摄取图像的方法来进行摄像机校准，由灭点正交性和单对应矩阵的固有特征估计摄像机内、外参数初值，通过非线性优化来最小化投影误差；利用遗传算法求解机器人手眼矩阵，避免了初值估计，可容易地得到机器人执行器末端相对于绝对坐标系的姿态．实验和计算验证表明，这种测量方法是有效的，可以用于机器人校准、机器人辅助测量以及机器人辅助手术等领域．     

刚体绕定点运动的等效转轴及转角

根据刚体运动学中的欧拉定理：刚体绕定点运动时的任何位移，可以绕通过定点的某一轴转动一次实现。本文用矢量绕与其相交的轴的转动公式及动坐标系绕原点转动时的坐标变换公式，导出了刚体绕直角坐标系的三个轴转动时对应的等效转轴的计算方法及转角的计算方法。     

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.     

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     

An affordable accurate evaluation of the binding conformations predicted by molecular docking studies in bio-system

Franck-Condon factors bridge the gap between theoretical modeling and experimental observations for molecular electronic spectroscopy and electron transfer.Under the displaced harmonic oscillator approximation,multidimensional Franck-Condon factors are decomposed into a product of many one-dimensional(1D)Franck-Condon(FC)factors,and each 1D-FC factor is associated with one Huang-Rhys factor that determines the leading contribution of     

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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