1R2T绳索牵引并联康复机器人绳索弹性研究

该文以平面三自由度(1R2T型)绳索牵引康复机器人为对象,分析了绳索弹性和绳索拉力对骨盆(动平台)静态刚度的影响,发现不同绳索弹性时,相同绳索拉力对动平台静态刚度影响不同。利用ADAMS软件对绳索拉力和绳索刚度的影响情况进行了机构仿真,发现绳索弹性对系统静态刚度的影响比绳索拉力大。分析并仿真了系统受外界干扰后的振动状态,结果表明,增大绳索拉力可以提高系统的抗干扰性。建立了考虑绳索弹性的动力学方程,以期望轨迹通过逆动力学方程计算出的绳索拉力作为系统动力学的输入,用ADAMS和MATLAB进行系统动力学仿真和实验,结果表明,绳索的弹性使骨盆的实际运动范围变小,且出现了位姿误差,距起始点越远该误差越大。     

基于虚拟样机的双足机器人步行联合仿真

为了提高双足机器人设计的效率与可靠性,利用机械系统动力学仿真软件ADAMS建立双足机器人的机械动力学模型,利用Matlab建立控制系统,通过ADAMS与Matlab的接口模块,实现了基于ADAMS与Matlab联合步行双足机器人仿真平台的建立.结果表明,仿真得出机器人在平地行走过程中各关节的力矩变化情况,获得了最高转速、有效转速、最大转矩、有效转矩等机器人运动的关键参数,为双足机器人物理样机的电机和减速器选型提供了理论依据.     

绳索牵引康复机器人控制及仿真研究

康复机器人是典型的人机合作系统．人与机器人在同一物理空间,因此对机器人的柔顺性、安全性提出了严格要求．绳索驱动具有柔顺性好、占空间小、重量轻等特点,不会与人体产生刚性碰撞、冲击,非常适合于康复机器人的驱动控制．由于绳索的柔性使其只能承受拉力,其牵引构成冗余驱动系统,因此绳索位置伺服系统须引入力控制,保证工作时绳索具有一定的张力．针对康复训练机器人的人体骨盆控制问题,设计了基于绳索驱动的伺服控制系统,通过Matlab提供的sisotool进行PI和PD控制器的设计,并对张紧力、位置和二者之间的相互影响进行了仿真分析,证明了绳索驱动适合对骨盆规律的控制,并且可以在其他绳索牵引控制技术上得到应用和推广．     

蠕动转向关节动力学建模与分析

为确立拱泥机器人蠕动转向关节的运动关系,提出了可实现直行和转向运动的3自由度并联机构动力学模型.基于对3-UPS并联机构运动特性的分析吗,首先建立了3-UPS运动学模型,得出3-UPS并联机构动平台和各支链的速度以及加速度关系式.基于Lagrange方程建立3-UPS并联机构的动力学模型,确立了系统的驱动力、驱动力矩以及各个支链主动杆的驱动力.利用Matlab软件对其动力学模型进行仿真分析,得到的驱动力和驱动力矩变化曲线为拱泥机器人控制系统设计提供了技术支撑.也为少自由度并联机构动力学分析提供参考.     

一种混合驱动的上肢康复外骨骼机器人设计

针对现有上肢康复外骨骼机器人的驱动问题,设计一种混合驱动的上肢康复外骨骼机器人,肩关节由电机直接与关节相连驱动,肘关节与腕关节由电机与绳索配合驱动。按照人体上肢解剖学结构设计出外骨骼机器人的本体结构和基本属性,分析肘关节运动原理,进行绳驱动关节张力分析,运用D-H法建立机器人的运动学模型,分析正运动学,通过ADAMS软件对机器人进行动力学仿真,运用CUBSPL函数作为驱动得出各关节的力矩变化,为后面各个关节电机的选型提供依据。     

球形机器人水下系泊状态水流干扰运动分析

为了使球形机器人能在复杂水域安全工作和利用能量,对其锚定状态下受水流干扰的运动规律进行分析.首先针对机器人的形体结构特点,应用线性波理论和Morision方程对流体载荷进行描述,并以机器人锚定系统方程为基础,引入波浪水动力、重摆扰动力和绳索弹性力项,建立了球形水下机器人锚定状态波流联合激励的动力学模型.然后在搭建的虚拟仿真验证系统中对机器人的位移、绳索拉力和重摆摆角进行仿真和验证,总结出绳索锚定角和拉力随流速增加呈非线性变化规律及机器人在波浪幅值影响下的波动特性,结合绳索张紧和松弛状态交替现象分析绳索拉力和重摆摆角异常波动原因.研究结果为球形机器人对流体波浪能的吸收和转化提供理论基础.     

跳跃机器人各关节的动力学仿真分析

基于跳跃机器人在越障方面优于轮动或爬行机器人的特点,设计了一个三关节跳跃机器人,并建立了简化的机构模型.从分析力学的角度对机器人进行运动分析,采用拉格朗日法建立了站立相和腾空相的动力学方程,并用Matlab对动力学方程进行了数值仿真.仿真结果表明各关节在电机驱动下有小幅度振动.这一结果说明在研究跳跃机器人的稳定性时,要解决各关节小幅度振动问题.     

采用Matlab的六自由度机器人三维运动学仿真

对SA1400型六自由度工业机器人进行三维的运动学建模与仿真,建立机器人的正逆运动学方程,并得到正逆解.为验证方程及所求解的正确性,首先,使用Solidworks建立机器人各个部件三维模型;然后,用Matlab将所求得的正逆解编写为程序,导入机器人各部件,利用Matlab的三维绘图功能,以显示机器人的三维模型,并对机器人按轨迹运动的过程进行动态仿真,记录运动过程中机器人各关节角度值的变化,提示求解得到的不合理角度值和奇异点.结果表明:仿真过程较真实地模拟了实际机器人的运动情况,仿真结果达到预期目标,证明根     

6自由度绳索牵引并联机器人的悬链线建模与动力学分析

针对6自由度大跨度绳索牵引并联机器人存在绳索悬链线效应的问题,分别建立了绳索的直线模型和绳索的悬链线模型,在此基础上推导了并联机器人的动力学模型,并对二者进行分析和比较.在绳索牵引并联机器人逆动力学的求解过程中,采用带约束的非线性优化方法作为求解工具来计算满足绳索单向力约束的绳索张力.仿真结果表明,考虑绳索的悬链线模型时,并联机器人逆动力学解得到的绳索末端张力与绳索的线性模型相比有很大的变化,故绳索悬链线效应不可忽略,动力学分析中必须加入绳索的悬链线模型.     

绳驱动仿腕关节绳拉力分布和可控刚度特性分析

为模拟人臂腕关节的结构功能,提出了有别于传统仿生关节的3自由度绳驱动并联结构,即通过球副连接动平台与静平台实现腕关节的转动功能。考虑绳驱动的冗余特性和绳索的单向受力性,对机构的位姿结构进行静力学分析,获得绳索张力表达式,同时建立绳张力分布优化模型,通过遗传算法得到绳拉力分布情况。通过建立运动学和静力学方程对机构进行受力分析,并引入线矢量和微分变换的方式,推导出机构的固有刚度和可控刚度,建立了腕关节静态位姿结构刚度模型,并给出刚度评价指标。分析绳索张力与机构刚度的关系和可控刚度对整体刚度的影响,数值仿真分析得出腕关节机构的位姿结构刚度在工作空间中的分布规律。     

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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