新型五自由度并联机床回零研究

基于栅格法提出了一种适合新型五自由度并联机床的两步回零法,即首先控制各驱动杆运动到事先经过标定的校准位置,并以此位置的标准值分别校准当前各个驱动杆的杆长,然后再驱动各杆回到规划好的初始零位,从而实现机床刀具的回零操作.同时,开发了相应的回零软件模块.该方法已应用于5-UPS/PRPU并联机床,实验证明:通过此方法可以准确可靠地实现该并联机床的回零操作.两步回零法避免了复杂的正解运算,且具有一定的通用性,对其它类型的并联机床也具有重要的参考价值.     

五自由度混联机构型综合的研究

提出了一种系统有效的混联机器人构型综合的新方法和单并联、多并联混联机构的概念及表示方法。根据螺旋理论构造了单开链五自由度串联机构;基于自由度分配原理,分析了可能出现的五自由度混联机构具体类型;将并联机构视为一个复合运动单元构型到串联机构中,替代串联机构中运动基相同且连续的若干运动单元,获得五自由度混联机器人构型;通过运动螺旋的线性组合来生成其他混联机构,并通过实例验证了该构型的正确性。分析表明该机构兼具串联机构和并联机构的优点。     

五自由度并联机床的误差分析

基于三杆五自由度并联机床机械结构,建立了误差分析数学模型。通过对并联机床静态误差分析,得到固定平台铰链点位置误差、伸缩杆长度误差对活动平台中心点位置误差影响的显式表达式,以及活动平台的姿态误差对活动平台中心点位置误差影响的显式表达式,为并联机床实时误差补偿提供了理论基础。     

新型五坐标并联机床的机构学及运动学

提出一种新型的五自由度并联机床,由于结构上的特殊设计,它比传统的并联机床具有更高的精度和刚度,更大的工作空间。主要介绍了所提出的并联机床的机构学和运动学,包括运动学的正逆解算法。     

串并联混合五自由度运动平台研究

基于串联机构与并联机构的不同特性以及伺服电机的优良控制特性,设计了一种串并联混合的五自由度运动平台,通过对平台并联机构的动力学分析,提出一种3-RPS并联机构正解几何算法。设计了基于C#语言的控制系统,并对系统的硬件与软件进行了介绍,控制系统可以实现平台运动范围内的精确控制,测试结果显示:平台平动定位精度优于10μm,转动定位精度优于0.01°。     

DSX5—70型三杆五自由度并联虚轴机床的运动仿真

基于开发研制的三杆五自由度并联虚轴机床，概述了实现虚轴机床三维实体模型数控加工的运动仿真方法，利用开发的虚轴模块，解决了在虚轴机床上实现CAD／CAM集成的难题，实现了三杆虚拟轴机床CAD／CAM的一体化、软件的模块化设计，使仿真系统具有良好的扩展性和通用性，操作方便。     

一种混联机床运动学建模及研究

为了研究少自由度结构的混联机构并联机床运动学问题,提高机床在加工过程中的运动控制精度,本文以一种五自由度新型重型混联机床-XNZH2430为例,分析了其几何结构,对该类型机构进行了深入的研究,推导并建立了其运动学正、逆解模型.     

基于3D打印技术的并联机器人机构精度分析

针对3D打印快速成型技术的性能需求,提出了一种基于3-UPU型三自由度3D打印并联机器人。对其中的3-UPU并联机构进行了运动学分析,在此基础上建立误差正解模型,考虑驱动副杆长误差和铰链间隙误差的影响因素,运用Monte-Carlo法分析了动平台末端精度的频数分布,求得了许用精度范围内的置信概率,为提高3D打印并联机器人机构末端的输出精度提供了重要依据,在生产制造业快速发展的主流技术中具有重要的研究意义与应用推广价值。     

五自由度摇摆台位置正解方法研究及 MATLAB实现

研究一种实用非对称五自由度摇摆台的位置正解算法.把描述五自由度摇摆台的一组非线性方程组的求解问题转化成对函数的优化问题,采用粒子群优化算法和Newton迭代法相结合的方法求解问题,并采用粒子群算法工具箱实现了五自由度摇摆台的位置正解.通过比较试验结果,发现采用PSO算法和Newton迭代法相结合的方法在精度方面比单纯采用PSO算法高,并且兼顾了实时性的要求.     

双足磁吸附五自由度爬行机器人运动学模型构建及求解

由于应用于特种行业及复杂工程领域的爬行机器人研究的重要性,在设计出一种双足磁吸附五自由度爬行机器人机械系统的基础上,以该五自由度爬行机器人的机构为研究对象,运用D-H参数法进行其运动模型构建,并通过矩阵变换,推导出了该机器人的正运动学解的齐次矩阵,并通过数学求解求出其逆解,然后采用MATLAB对该机器人的运动数学模型进行仿真分析,得出其正解和逆解。将仿真结果与计算结果进行对比分析,验证了所建立的五自由度爬行机器人运动模型的正确性。该研究对于开发五自由度爬行机器人的控制系统及控制策略,以及它在具体工程实践中的应用具有重要的研究基础作用。     

A New 3-DOF Spatial Parallel Mechanism for Milling Machines with Long X Travel

It is well known that the shape and volume of the workspace are one of the greatest weaknesses of parallel kinematic machine tools (PKM). Hexaglide and Triaglide mechanisms are examples where workspace extension is achieved by elongating one axis as a principal motion axis that is a common feature of all Cartesian machines. With the idea of principal axis of motion in mind, a new 3-DOF spatial parallel mechanism for horizontal and vertical milling machines has been developed. In comparison with similar developed mechanisms it has several advantages such as: rather regular shape of the workspace (slightly modified block) similar to serial machines; greater stiffness by nature of the struts arrangement; good force and speed ratio through the entire mechanism's workspace. The paper describes the structure of the mechanism, modelling approach and simulation on a developed vertical milling machine prototype.     

5-UPS/PRPU五自由度并联机床基准位形的确定

确定了5-UPS/PRPU五自由度并联机床的刀尖点的空间搜索范围,计算出该搜索范围内动平台的位姿,将这些动平台位姿进行几何约束条件的检验,通过对满足几何约束条件的动平台位姿的雅可比矩阵的3个灵巧度指标分析,以综合误差系数为机床性能评价指标,搜索出并联机床的基准位形,为并联机床工件坐标系定位算法的研究提供了理论基础。     

Design of a 4-DOF hybrid PKM module for large structural component assembly

This paper presents a novel 4-DOF hybrid parallel kinematic machine (PKM), named Bicept, comprising a 2-DOF parallel mechanism plus a 2-DOF rotating head. The PKM is designed as a rigid yet compact module that can act as a robot cell moving along a long track for aircraft structural component assembly, a wing box for example. Dimensional synthesis of the 2-DOF parallel mechanism is carried out to achieve a relatively good kinematic performance within a prescribed task workspace that has a large width/height ratio. Then, using commercial CAE software, rigid body dynamics and stiffness analyses are carried out for motor sizing and performance evaluation of a full-size virtual prototype.     

新型并联机床的力／运动传递各向同性性能及其分布

以并联机器人机构为原型的并联机床,其力/运动传递各向同性性能是随其运动平台的位姿变化而变化的。本文应用并联机器人机构学理论,提出基于6-SPS并联三维平台机构的新型6自由度并联机床的力/运动传递各向同性性能评价指标,并给出这些指标在定位姿工作空间内的分布情况,这对该结构形式的并联机床的设计及其任务规划和控制有重要意义。     

Holistic modelling of process machine interactions in parallel milling

Parallel milling allows to increase the manufacturing capacity in industry due to a higher cutting productivity. The latter is often negatively influenced by dynamical instabilities of the parallel milling process entailing a reduced profitability. In this paper a holistic model of interactions between a double spindle machine and a parallel milling process is presented that enables an identification of the dynamic compliance of parallel milling machines and a simulation of their stability behaviour. With that an investigation of stability optimization means is possible. A significant improvement of the process stability and, thus, the effective cutting productivity was observed in the parallel milling processes, optimized with help of the holistic model.     

新型6-SPS三维平台并联机床工作空间研究

工作空间是并联机床的重要性能指标。研究了一种以 6 -SPS并联三维平台机构为原形的新型 6自由度并联机床的工作空间 ,基于位置反解方程并考虑其结构约束条件 ,求出其定位姿工作空间任意截面的轮廓图 ,分析了机床结构参数对工作空间大小的影响 ,这对该并联机床的合理设计和使用很有意义。     

燃汽轮机缸体倾斜孔数控铣削加工参数化编程

在机械加工中,常会遇到与机床主轴不垂直的空间大斜孔系的铣削加工。在三轴联动的数控镗铣床上,采用万向角度铣头改变机床主轴方向,使孔轴线与铣刀轴线一致,运用空间几何建立各加工变量之间的数学模型,实现空间斜孔铣削加工数控程序参数化。结果表明:只需一次装卡工件,赋予相应变量值,就可完成孔系的加工。该方法的加工精度高,省工省力,可推广到类似空间斜面、倾斜槽的加工。     

辅助工装的设计与万向轴法兰叉头端面齿的加工方法

针对万向轴法兰叉头端面齿形结构的特点,设计了一种辅助工装,利用该工装,在不改变X6142A万能升降台(或X5042A立式升降台)铣床本身结构的基础上即可对法兰叉头端面齿同时进行六齿加工。     

A systematic optimization approach for the calibration of parallel kinematics machine tools by a laser tracker

Parallel kinematics machine has attracted attention as machine tools because of the outstanding features of high dynamics and high stiffness. Although various calibration methods for parallel kinematics machine have been studied, the influence of inaccurate motion of joints is rarely considered in these studies. This paper presents a high-accuracy and high-effective approach for calibration of parallel kinematics machine. In the approach, a differential error model, an optimized model and a statistical method are combined, and the errors of parallel kinematics machine due to inaccurate motion of joints can be reduced by this approach. Specifically, the workspace is symmetrically divided into four subspaces, and a measurement method is suggested by a laser tracker to require the actual pose of the platform in these subspaces. An optimized model is proposed to solve the kinematic parameters in symmetrical subspaces, and then arithmetical mean method is proposed to calculate the final kinematic parameter. In order to achieve the global optimum quickly and precisely, the initial value of the optimal parameter is directly solved based on the differential error model. The proposed approach has been realized on the developed 5-DOF hexapod machine tool, and the experiment result proves that the presented method is very effective and accurate for the calibration of the hexapod machine tool.