冗余驱动并联机械手的混合位置/力自适应控制

针对冗余驱动并联机构研究一种自适应的混合位置/力控制算法.基于并联机构中约束 子流形的几何性质,将冗余驱动并联机构的逆动力学自然投影到位形空间和约束力空间.基于投 影方程,提出一种统一的具有渐进稳定性的自适应混合位置/力控制算法.采用最小二范数准则 求解冗余解问题,实现了实际驱动关节力矩的优化.仿真结果验证了控制方法的有效性.     

5自由度并联机器人设计方法

本论文以螺旋理论为基础,提出一种系统的结构综合方法.根据各条支链对运动平台所提供的反螺旋 约束的线性关系,研究了构成五自由度并联机器人机构的各条支链所有可能的运动副组合以及它们的空间几何条 件.利用这一方法,设计出一组结构对称的五自由度并联机器人.     

柔索驱动三自由度球面并联机构运动学与静力学研究

柔索驱动并联机器人采用柔索代替连杆作为机器人的驱动元件,它结合了并联结构和 柔索驱动的优点．文章提出了一种新型带有约束机构的并联柔索驱动机器人，采用四根柔索 驱动．由于约束机构的引入，机器人可实现在空间的三维转动．介绍柔索驱动并联机器 人的机构构型，给出了位姿逆解，建立了静力平衡方程和运动学方程，讨论了柔索拉力的确 定方法．研究结果证明在加入了约束机构后，柔索机器人可以实现更多的运动形式，这就为 更广泛的应用柔索驱动成为可能．     

并联2-RRR/UPRR 踝关节康复机器人机构及其运动学

在分析现有踝关节康复机器人机构特征的基础上,提出了一种具有远程转动中心的2-RRR/UPRR 并联 踝关节康复机构．该机构可以实现踝关节康复运动所需的三自由度转动,即内翻／外翻,背屈／跖屈,外展／内收运 动．采用关节轴线的运动副螺旋矢量表示法分析了该机构在整个工作空间内任意位姿都可以实现3 维转动的机构学 原理．计算了其自由度,并讨论了选取与定平台相连接的3 个转动副作为输入的合理性．应用球面几何方法给出该 机构的位置反解,同时推导出机构位置正解表达式,并给出了数值算例,验证了其工作空间满足踝关节康复运动的 要求．     

智能材料DE 驱动的两态串并联机器人系统的运动特性

本文利用电活性绝缘弹胶体DE 的机电驱动特点,结合两态驱动的概念,设计了一种包含3 个两态驱 动器件的并联机构,将其作为串—并联离散驱动机器人系统的基本单元,并据此构建多个单元串联组成的多级离散 驱动系统．文中首先利用智能DE 材料制作满足这一驱动特性的圆柱形两态驱动器件,先测试其直线驱动特性,即 变形值．其次,将该变形值作为并联机构数学模型的驱动值,分析单级及多级并联机构的运动状态、特性及工作空 间的特点．最后,利用数学工具Mathematica 描绘出上述两态驱动并联机构系统所能达到的工作空间分布点云图, 分析了结构参数与驱动量对系统工作空间的范围、精度的影响．     

耦合型3自由度并联稳定平台机构及其运动特征

基于舰船摇荡运动的耦合特征,采用耦合型3-SRR/SRU 3自由度并联机构作为舰载稳定平台机构,实现了稳定平台三轴驱动、动平台五轴联动补偿的目标．运用螺旋理论分析了机构的自由度和运动特征, 并讨论了输入关节选取的合理性|采用坐标等效运动的方法,建立机构耦合运动约束方程,得到了位置解及工作空间．本文将耦合型3-SRR/SRU 3自由度并联机构用于舰载稳定平台五轴联动补偿,拓展了少自由度并联机构的应用领域．     

平面并联机构工作空间的三维螺旋扫描CAD求解

针对平面并联机构无奇异位置工作空间求解困难、过程繁琐、计算量大等问题，提出了基于CAD求解平面并联机构工作空间的三维螺旋扫描方法。将[n]自由度平面并联机构分解成[n]条支链进行独立分析，得到每条支链下末端执行器的可达区域，再将所有支链可达区域取交集即为平面并联机构工作空间。应用SolidWorks软件建立平面并联机构模型，进行几何特征处理，通过自动求解器求解，将求解过程图形化，快速得到同轴布局5R机构和平面3-RPR并联机构的无奇异位置工作空间。通过同轴布局5R机构的运动学实验，验证了该求解方法的可行性。     

三分支机器人协调操作及关节力矩优化

针对三分支机器人协调运动，采用分离影响系数法分离各个分支的雅可比矩阵和惯性矩阵，再重新组合成整个系统的雅可比矩阵和惯性矩阵，建立三分支机器人运动学和动力学方程．应用乘子罚函数方法，对三分支机器人基于最小关节驱动力矩优化设计,避免矩阵的奇异值分解，提高计算的稳定性，应用迭代方法，简化了问题的求解．     

平面全柔性3-DOF过驱动并联机构的最优综合

以设计全柔性多自由度过驱动并联机构为目标，研究了平面3-DOF 4RRR过驱动并联机构的最优综合问题．从一般四分支3-DOF平面并联机构出发，建立了机构的运动学模型；给出了机构的4种可能拓扑结构分类，对不同拓扑结构类型机构的运动学和力学性能进行了分析比较．建立了并联机构全工作空间操作性改善优化模型，采用遗传算法进行优化设计并给出了实例，根据优化实例的结果设计制造了平面全柔性三自由度过驱动并联机构．以上方法对其它全柔性并联机构的优化设计具有参考价值．     

生物融合式康复机构及其应用

按照机械与人体不同的相互作用关系对康复器械的机构进行分类，提出了生物融合式康复机构的概念 并介绍了其特征．在分析踝关节及其现有康复器机构特征的基础上，应用生物融合式康复机构的概念设计了一种含 有弹性元件的并联踝关节康复机构，该机构可以实现踝关节内翻／外翻、背屈／跖屈、外展／内收康复运动，还可以对 踝关节进行牵引．分析了该机构的输出自由度、结构自由度和驱动合理性．计算了踝关节在康复运动过程中机械驱 动和生物驱动的输入量，以及两组驱动给定后踝关节的姿态．以对踝关节进行背屈／跖屈康复训练为例，给出该机构 机械分支受力和机械驱动随踝关节姿态变化的曲线．     

Analytical Identification of Limb Structures for Translational Parallel Manipulators

A systematic analytical method, based on the theory of screws, is presented for identification of limb structures of general and over‐constrained 3‐degree‐of‐freedom (DOF) translational parallel manipulators. Given a system of wrenches of constraint, the corresponding reciprocal basis screws are determined. Then, the joint screws of a limb are obtained by a linear combination of these basis screws. Feasible limbs that can be used for construction of translational platforms are enumerated according to the type of constraint and the number of joints making up the limbs. © 2004 Wiley Periodicals, Inc.     

Reconfigurability and unified kinematics modeling of a 3rTPS metamorphic parallel mechanism with perpendicular constraint screws

This paper investigates reconfigurability and unified analytical kinematics analysis of a new 3rTPS metamorphic parallel mechanism consisting of three reconfigurable rTPS limbs in perpendicular base planes. Constraint screw systems show that in one phase the rTPS limb has no constraint to the platform and in the other phase obtained by altering the reconfigurable Hooke joint, it provides a constraint force. The two phases of the limb qualify the 3rTPS metamorphic parallel mechanism to have four topologies with ability of mobility change among 3R (three rotations), 3R1T (three rotations one translation), 3R2T and mobility 6. By considering the difference of the two phases of the limb, a unified kinematics modeling is proposed based on the actuation scheme analysis by taking one phase as a special case of the other. Following this, a unified kinematics modeling of the 3rTPS metamorphic parallel mechanism is obtained by covering all its four topologies. Both inverse and forward kinematics analysis are solved analytically and numerical examples confirm these theoretical results.     

A Linear Algebraic Procedure in Obtaining Reciprocal Screw Systems

This paper presents a linear algebraic procedure in obtaining (6?n) reciprocal screws from an n‐screw system of a robotic manipulator. The procedure starts by formulating the reciprocal relationship between a screw system and its reciprocal screw system in matrix form, and augmenting the screw matrix which is assembled with n screws in the screw system. Vectors of cofactors of the augmented row are then produced and the partitioning of the screw matrix is implemented to generate each of the (6?n) reciprocal screws. The theory developed in this paper provides a novel and simple procedure to obtain reciprocal screws from any screw system. The paper illustrates applications to cases with different screw systems. © 2003 Wiley Periodicals, Inc.     

基于螺旋理论的新型三自由度移动并联机器人奇异性分析

采用螺旋理论及线性几何学方法对具有3支链5关节（P-4R）的三自由度纯移动并联机器人的奇异性进行了分析和总结．研究了该并联机器人的结构奇异性以及主动关节（驱动关节）的配置的奇异性，并采用线性几何学图解形式直观地给出其处于奇异时的形位，为进一步研究其动力学、运动学性质奠定了基础．     

Translational Parallel Manipulators: New Proposals

Translational parallel manipulators are parallel manipulators wherein the end‐effector performs only spatial translations. This paper presents a new family of translational parallel manipulators. The manipulators of this family are independent constraint manipulators. They have three limbs that are topologically identical and have no rotation singularity. The limbs of these manipulators feature five one‐degree‐of‐freedom kinematic pairs in series. Four joints are revolute pairs and the remaining one, called T‐pair, is a kinematic pair that can be manufactured in different ways. In each limb, three adjacent revolute pairs have parallel axes and the remaining revolute pair has an axis that is not parallel to the axes of the other revolute pairs. The mobility analysis of the manipulators of this new family is addressed by taking into account two different choices for the actuated pairs. One of the results of this analysis is that the geometry of a translational parallel manipulator free from singularities can be defined for a particular choice of the actuated pairs. © 2002 Wiley Periodicals, Inc.     

Review: Don't Cross‐Thread the Screw!*

The screw is a geometrical element. As Sir Robert Ball stated a century or more ago, the screw joins the company of point, plane, and line. In mechanics, especially instantaneous kinematics and statics of rigid bodies, angular and translational velocity of a body combine as a twist on a screw; precisely analogously a force and a couple combine as awrench on a screw. In three dimensions screw theory provides essential and simple insight into the behavior of systems of jointed bodies. And screw theory can also play a leading role in the systematic selection of suitable geometrical patterns that should relate to such jointed systems. Yet the mechanics of robots—the prime example today of systems of jointed bodies—has developed with little respect for the screw, even at the most elementary level. Here I focus mainly on robot performance, the study of which has, to an excessive extent, been proceeding blindly in territory where there is an abundance of screws and systems of screws, all, as it were, shouting to be taken on board to show the way. Failure to recognize the screw, and an unwillingness to use it properly, has led to the screw's being violently abused—“cross‐threaded.” There are far too many examples of “cross‐threading” that have, regrettably, appeared in recent years in several well‐known journals. Offenses have been perpetrated and yet left unchallenged. Here I try to remove any mystery that some may see surrounding, and even concealing, the screw. I then venture to deal critically with a small selection of the many instances of cross‐threading. However, this symposium has as a main objective the celebration of a Centenary. So it betokens an element of light‐heartedness that I resort to at times within the pages that follow. © 2003 Wiley Periodicals, Inc.     

基于静电力的微液滴驱动芯片

为了精确操控微流体,设计并制作了一种基于静电力的微液滴驱动芯片.介绍了驱动原理和工艺流程,搭建了驱动检测实验平台.芯片采用开放式的结构,只需单层共平面控制电极,以硅作衬底,氧化硅和多晶硅作绝缘层,重掺杂多晶硅为驱动电极阵列,高质量Si3N4作介质层,碳氟聚合物为疏水层.实验表明:微液滴可在芯片上按程序设定方式在二维平面...     

Effects of two ergonomic aids on the usability of an in-line screwdriver

We assessed the effects of two ergonomic aids on the usability of an in-line screwdriver. The simple aids considered were a hand support and a sleeve which softened the handle. In an experiment, 15 subjects drove screws into horizontal plywood plates with four combinations of a screwdriver and an ergonomic aid. The activities of four forearm muscles (EMG) and the force acting on the screw were measured. The subjects rated the properties of the tools as regards physical exertion, the ease of taking hold of the tool, comfort of the grip, and the surface texture. The hand support and the sleeve had positive effects on the subjective perception of exertion and the surface texture, respectively. Differences in EMG and thrust force along the shaft of the screwdriver handle were found to be too small for reliable deductions in the effects of the ergonomic aids.     

Singularity condition of six-degree-of-freedom three-legged parallel robots based on grassmann-cayley algebra

This paper addresses the singularity condition of a broad class of six-degree-of-freedom three-legged parallel robots that have one spherical joint somewhere along each leg. First, the actuator screws for each leg-chain are determined. Then Grassmann-Cayley algebra and the associated superbracket decomposition are used to find the condition for which the Jacobian (or rigidity matrix) containing these screws is rank-deficient. These tools are advantageous since they facilitate manipulation of coordinate-free expressions representing geometric entities, thus enabling the geometrical interpretation of the singularity condition to be obtained more easily. Using these tools, the singularity condition of (at least) 144 combinations of this class is delineated to be the intersection of four planes at one point. These four planes are defined by the locations of the spherical joints and the directions of the zero-pitch screws.