非球型手腕6R机器人实时逆运动学算法

针对非球型手腕6R机器人,设计并实现了满足工业实时性和高精度要求的逆运动学算法.采用基于Liu方法的析配消元过程和雅可比伪逆法相结合的逆解方法,析配消元过程中引入矩阵条件数来确保选出更"好"的矩阵作进一步计算,对于矩阵条件数过大或矩阵无实数域特征值的情况,切换到雅可比伪逆法,使得原Liu方法不可解的位置(即关键矩阵均不满秩的情况)可以求解.对任一型号的6R机器人只需要一次符号计算得到各关键矩阵,然后将一元16次方程的求解转化为矩阵特征值的求解,减少了累积误差,提高了运算精度.实验结果表明:提出的算法平均计算时间为0.37ms,描述机器人末端位姿误差的综合指标达到1×10-10以内.     

基于Groebner基法的一般串联6R机器人机构逆运动学分析

基于Groebner基法，仅用Duffy的含3个未知变元的4个运动学方程，附加3个正余弦恒等式，不增加其他几何约束方程，对一般6R机器人机构逆运动学进行符号解分析，并得出一般串联6R机器人机构逆解最多为16解的结论．本文使用的数学机械化方法可推广到涉及非线性代数方程组的其他机构学问题的求解．     

阀体喷涂机器人运动学分析及能效匹配设计

针对管道阀门喷涂作业需求,提出了非球形手腕6R喷涂机器人构型和双工位机器人自动喷涂生产线方案;完成喷涂任务的无冗余工作空间及相应的杆长、关节转角范围.基于ADAMS和MATLAB软件的联合仿真,求解了机器人以折线轨迹喷涂阀体时的运动学逆解;提出了喷涂生产线的能效匹配设计方法,以确保机器人喷涂效率和生产线工序节拍达到无缝对接,并通过机器人自动喷涂测试进行了验证.     

基于四元数矩阵与Groebner基的6R机器人运动学逆解算法

为促进一般6R机器人运动学逆解的应用,提出了一种四元数矩阵和对偶四元数矩阵算法,该算法把四元数应用于平面旋转的特殊情况,把旋转角度的正弦、余弦改写为矩阵形式,可以导出平面四元数的2个矩阵形式的基,建立了四元数矩阵形式的串联6R机械手运动学方程,再通过线性消元和2次应用分次字典序Groebner基消去5个变元,最后采用Dixon结式进行消元,得到没有增根的一元16次方程。这种算法得出的结果通过与过去得出的6R机器人逆解算法进行对比,表明所提出的算法可行性和正确性。     

基于分块矩阵的6R机器人实时逆解算法

为提高6R机器人逆运动学求解的强实时性,提出了一种基于分块矩阵相乘来求解逆运动学的方法。将复杂的6个矩阵方程转换为含有6个未知变量的8个纯代数方程来进行求解,并在方程简化过程中引用符号运算预处理,避免了大量浮点运算带来累积误差。通过方程组的优化,可避免第3关节变量求解中产生增根的情况。试验结果表明,在同等精度要求下,该逆解算法相比于其他算法具有更强的实时性,得到精确的8组封闭解平均仅需0.009 7 ms,能够满足机器人的在线控制要求。     

5 自由度机器人操作器运动学逆问题的解析解

为求解5自由度机器人操作器的运动学逆问题,本文提出了一个完整的简化求解方程组,并利用此方程组求得具有解析解的5自由度操作器的8类结构形式及具有球型手腕的6自由度操作器的运动学逆问题的解析解.     

连续3R斜交非球型手腕的设计与运动学分析

针对机器人手腕结构类型和轿车喷涂作业要求，提出一种中空结构的斜交非球型3R手腕的概念设计．手腕外壳由两段变径管和一个法兰构成，内部是由中空的锥齿轮、直齿轮和轴组成3个机械传动链；手腕整体结构紧凑，灵活度大，能实现三维空间内的任意姿态；同时用矩阵分析的方法对这种手腕进行了运动学建模和工作空间分析，并用ADAMS软件进行了运动学仿真，仿真结果和理论计算值一致，表明手腕的结构设计方案可行．     

利用共形几何代数的串联机器人位置逆解求解方法

为获得串联机器人位置逆解的解析解,使用共形几何代数对串联机器人位置逆解进行了研究。利用共形几何代数中基本几何元素的内积和外积运算,获得串联机器人各关节点的位置,然后通过构造经过关节点的直线与直线以及平面与平面的内积,求解出机器人所有关节转角,从而直接获得了串联机器人位置逆解的解析解。该方法求解简捷,几何直观性好,避免了经典机器人运动学理论中欧拉角、矩阵的运算以及复杂的多元高次非线性方程组求解,求解过程和结果可以明显地反映机器人几何结构与机器人运动之间的几何关系。以一种空间6R串联机器人位置逆解为例进行了求解,算例计算表明该方法正确、有效,计算效率提高了近44倍。     

一种6自由度关节机器人逆运动学共形几何代数法

为获得一种6R(R为转动副)焊接机器人运动学逆解,使用共形几何代数(CGA)对焊接机器人运动学进行研究.利用共形几何代数中基本几何元素的表达以及几何形体的内积和外积运算,获得了焊接机器人各关节点的位置;通过构造经过关节点的直线与直线以及平面与平面的内积,得出机器人所有关节转角余弦表达,从而获得了焊接机器人位置逆解所有解析解.最后,以一种空间6自由度关节机器人为例求解运动学逆解,结果表明,新方法正确有效,几何直观性好.     

机器人逆运动学的微分进化与粒子群优化BP神经网络求解

针对采用传统反向传播(BP)神经网络算法进行逆运动学求解收敛速度慢的问题,提出将微分进化(DE)与粒子群优化(PSO)算法相结合,对用于机器人逆运动学求解的BP神经网络进行优化。基于机器人正解映射建立优化算法的目标函数,在PSO过程中,引入DE操作优化粒子进化方向,并将此混合算法用于BP神经网络权值与阈值的优化。对KUKA机器人进行仿真实验,结果表明:采用该文方法对机器人逆运动学问题的求解精度高,求得的关节角度误差小于0.1°;逆运动学求解结果所对应位姿矩阵的位置误差在0.1 mm数量级,具有较好的泛化能力。该文方法满足机器人位置和姿态方面的精度要求。     

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.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

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