一种新型3P6R混联机械臂及其位置分析

提出了一种新型3P6R混联机械臂--平面3自由度串并混联机构,基于这种混联机械臂的结构布局形式,建立了其位置正、反解方程式,并得知其位置正、反解均有唯一封闭解,在满足其结构约束条件的情况下,绘制了其工作空间轮廓图,给出了末端件极限姿态角在工作空间内的分布情况,为这种混联机械臂的实用化提供了理论基础.这种混联机械臂具有工作空间大、刚度大、惯性小和工艺性好等优点,可应用于汽车、造船、航空等现代工业领域.     

工作空间测量定位系统加权问题研究

工作空间测量定位系统(workspace Measuring and Positioning System,简称wMPS)是一种基于旋转激光扫描平面定位技术的室内大尺寸定位系统。它可实现计量精度的三维坐标测量,主要应用于制造加工及装配领域。作为一种分布式系统,工作空间测量定位系统也存在着为不同测量节点分配权重的问题。考虑到在定位过程中误差的复杂性,提出一种根据不同测量区域,利用统计数据对不同测量节点动态分配权重的分权方法。为验证此方法,设计了对比实验,实验结果表明:文中提出的加权方法可显著提高工作空间测量定位系统的测量精度。     

求解并联机床工作空间的算法分析和研究

本文针对三自由度并联机床的机构进行了分析,并求出了其位置逆解。在此基础上对求解其工作空间所采用的算法进行了研究和分析,重点给出了边界搜索法的设计方法,并进行了相关算法的分析。结果表明,在机构没有空洞的情况下,边界搜索法是一种理想的求解工作空间的算法     

Extreme reaches and maximal reachable workspace for rotary tools mounted on a Stewart platform manipulator

Abstract

A new type of problem associated with the extreme reaches of the Stewart platform manipulator is dealt with in this paper. Given a specified orientation of the tool axis, the problem involves finding the extreme distance that the tool bit mounted on the mobile platform can reach from its home position along any specified direction. During the motion, the mobile platform is allowed to be rotated about the tool axis to adjust the configuration of the driving mechanism to prevent premature activation of the kinematic constraints. A numerical optimization algorithm based on the concept of the cyclic coordinate descent method is developed for solving this problem, in which all three types of kinematic constraints, namely the actuator stroke constraint, the passive joint limitations, and the link interference conditions, have been taken into account. In addition, a numerical example is presented to demonstrate the ability of the proposed method to find the optimal reachable workspace of the robot.     

Optimization of a planar tendon-driven parallel manipulator for a maximal dextrous workspace

In this article, new methodologies for determining the tension distribution and optimal configurations of planar tendon-driven parallel manipulators (TDPMs) are presented. TDPMs are characterized by the use of cables in place of the linear actuators used in most parallel manipulators. Three separate, but inter-related topics are examined in this article, and methodologies for addressing them are proposed. The first is the determination of cable forces for overconstrained tendon-driven manipulators, which is necessary in order to address the second topic, namely, the development of a methodology for workspace determination of tendon-driven manipulators. The final topic examined is the dimensional synthesis of tendon-driven manipulators for a large dextrous workspace. The numerical methodologies developed here have potential for easy application to more complex spatial cases.     

A method for analytically generating three-dimensional isocomfort workspace based on perceived discomfort

The purpose of this study was to develop a new method for analytically generating three-dimensional isocomfort workspace for the upper extremities using the robot kinematics. Subjective perceived discomfort scores in varying postures for manipulating four types of controls were used. Fifteen healthy male subjects participated in the experiment. The subjects were asked to hold the given postures manipulating controls for 60 s in the seated position, and to rate their perceived discomfort during the following rest of 60 s using the magnitude estimation. Postures of the upper extremities set by shoulder and elbow motions, types of controls, and left right hand were selected as experimental variables, in which the L32 orthogonal array was adopted. The results showed that shoulder flexion and adduction-abduction, elbow flexion, and types of controls significantly affected perceived discomfort for postures operating controls, but hand used for operating controls did not. Depending upon the types of controls, four regression models predicting perceived discomfort were presented. Using the models, a sweeping algorithm to generate three-dimensional isocomfort workspace was developed, in which the robot kinematics was employed to describe the translational relationships between the upper arm and the lower arm/hand. It is expected that the isocomfort workspace can be used as a valuable design guideline when ergonomically designing three-dimensional workplaces.     

双臂机械手工作空间

双臂机械手与单臂机械手比较,能较好地完成装配和搬运重物等工作。当双臂机械手搬运物体从一个位置到另一个位置时,机架、两个臂和被夹持物体构成一个封闭系统。双臂机械手的运动将受到两手部夹持器与被夹持物体之间相对位置和姿态的影响。本文提出了确定双臂机械手搬运物体时的工作空间的方法。建立了数学模型和约束方程;提出了优化的目标函数和设计变量。在文中还研究了确定双臂机械手公共工作空间的方法。导出了双臂机械手公共工作空间的边界轮廓方程,最后给出一个数字实例来说明。     

Dexterous workspace optimization of an asymmetric six-degree of freedom Stewart–Gough platform type manipulator

In this paper, an asymmetric Generalized Stewart–Gough Platform (GSP) type parallel manipulator is designed by considering the type synthesis approach. The asymmetric six-Degree Of Freedom (DOF) manipulator optimized in this paper is selected among the GSPs classified under the name of 6D. The dexterous workspace optimization of Asymmetric parallel Manipulator with tEn Different Linear Actuator Lengths (AMEDLAL) subject to kinematics and geometric constraints is performed by using the Particle Swarm Optimization (PSO). The condition number and Minimum Singular Value (MSV) of homogenized Jacobian matrix are employed to obtain the dexterous workspace of AMEDLAL. Finally, the six-DOF AMEDLAL is also compared with the optimized Traditional Stewart–Gough Platform Manipulator (TSPM) considering the volume of the dexterous workspace in order to demonstrate its kinematic performance. Comparisons show that the manipulator proposed in this study illustrates better kinematic performance than TSPM.     

3-TPT型并联机器人工作空间解析与综合

以3-TPT并联机构为对象，构造出受杆长和虎克铰约束的工作空间边界及灵活度解析模型。结合灵活度分析，探讨了结构参数对3-TPT并联机器人工作空间的影响规律，提出了一种结构参数设计方法。     

机器人工作空间快速可靠数值算法

本文根据机器人的结构特点,选定机器人工作空间的中心点,利用机器人手臂端部在各个方向上到中心点的极限距离,设计出一种快速可靠的机器人工作空间数值算法.该算法比其他数值算法计算量少一个量级,且可靠性好.