共查询到19条相似文献,搜索用时 166 毫秒
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提出了一种新型六自由度并联机构,该机构由两条运动支链组成,每条支链各包含一个主动球副。与常规六自由度并联机构相比,支链数目的减少可有效增大机构工作空间。基于封闭矢量法求得所提机构的运动学位置逆解,在此基础上分析了机构输入与输出的速度映射关系,建立了机构雅可比矩阵。以工作空间和全域灵巧度为性能评价指标,借助性能图谱法完成了机构尺度设计,基于该尺度参数,对特定工作姿态下的工作空间、灵巧度、承载性能及刚度性能进行了全面研究。最后,搭建了3D打印样机,并对其典型应用场景进行了分析。 相似文献
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以一种新型三自由度并联机床为研究对象,建立了该机床的运动学正、反解方程,推导出了该机床的雅可比矩阵及雅可比逆矩阵,并在此基础上对该机床的奇异性及平稳性进行了研究,仿真出了该机床各驱动杆伸缩速度变化曲线.该研究为并联机床结构最优化设计及性能分析提供了一定的理论依据. 相似文献
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研究了并联机床的灵巧度评价指标及其在实际加工中的应用。介绍了一种新型的五自由度并联机床,该机床机构具有五个驱动分支和一个约束分支,可以实现三维移动和二维转动。建立了该机床机构的雅可比矩阵,得到了三个影响机床机构灵巧度的指标,即条件数、最小奇异值、可操作性;并通过对这三个并联机床灵巧度评价指标进行分析,定义了两个灵巧度的综合评价指标-综合灵巧度系数和综合灵巧度,分别作为评价不同位形下灵巧度和整个刀位文件灵巧度的指标。最后,介绍了在实际加工中对不同加工轨迹的灵巧度进行综合评价的方法。实验结果表明:机床实际加工100平面圆,对各向同性有较高要求时的最优加工轨迹为z=650 mm,保证了机床加工过程中应具有良好运动和动力学性能的要求。 相似文献
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六足步行机器人的并联机械腿设计 总被引:5,自引:0,他引:5
将并联机构用于六足步行机器人的腿部结构,以拓展六足步行机器人的应用领域.提出了一种基于(U+UPR)P+ UPS机构的并联机械腿,并对机械腿进行了结构参数设计.首先,对腿部机构进行了运动学分析,推导出了腿部机构的位置反解方程和速度传递方程;分析了腿部机构的工作空间并绘制了工作空间三维图,定义了工作空间性能评价指标,绘制了结构参数与工作空间性能指标的关系曲线.然后,对腿部机构进行了运动灵活性分析并绘制了雅克比矩阵条件数分布图,定义了运动灵活性评价指标,绘制了结构参数与运动灵活性指标的关系曲线.最后,基于工作空间性能指标和运动灵活性指标,采用蒙特卡罗法进行了结构参数分析,选取了一组性能较好的结构参数并考虑加工和装配工艺性,设计了一种新型3自由度并联机械腿的虚拟样机,为六足步行机器人的进一步研究奠定了基础. 相似文献
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Sanjay Darvekar A. B. Koteswara Rao S. Shankar Ganesh K. Ramji 《The International Journal of Advanced Manufacturing Technology》2013,67(5-8):1609-1621
This paper presents multiobjective optimization of a typical 2-degree-of-freedom (DOF) parallel kinematic machine (PKM) tool that has only single DOF joints. Nondimensional indices, namely global stiffness index (GSI), global conditioning index (GCI), and workspace index, are considered as the objectives for optimization. The indices GSI and GCI depict the variation of stiffness and dexterity of PKM within the workspace. The leg length and distance between two rails on which actuators slide are treated as design variables as these greatly influence the characteristics of PKM. A multiobjective genetic algorithm (MOGA) approach is implemented in MATLAB to find an efficient solution to this complex optimization problem. Fitness function includes inverse kinematics equations, Jacobian and stiffness matrices to compute and optimize the nondimensional indices. First, the optimal value of each index is obtained by single-objective GA. To further improve the results, a hybrid function PATTERNSEARCH is used. This helps to select appropriate boundary conditions for MOGA. To obtain the optimal values of all the three indices, a multiobjective GA is carried out. The results are compared with a conventional exhaustive search method of optimization. The obtained results show that the use of MOGA enhances the quality of the optimization outcome. Secondly, a prototype has been designed and developed with the optimal dimensions. The actual workspace of the PKM and influence of leg collision on the workspace are studied. Finally, a preliminary experimentation was carried out. A comparison between PKM and the three-axis serial kinematic machine tool is presented. 相似文献
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The research on the parameters optimization for gasbag polishing machine tools, mainly aims at a better kinematics performance and a design scheme. Serial structural arm is mostly employed in gasbag polishing machine tools at present, but it is disadvantaged by its complexity, big inertia, and so on. In the multi-objective parameters optimization, it is very difficult to select good parameters to achieve excellent performance of the mechanism. In this paper, a statistics parameters optimization method based on index atlases is presented for a novel 5-DOF gasbag polishing machine tool. In the position analyses, the structure and workspace for a novel 5-DOF gasbag polishing machine tool is developed, where the gasbag polishing machine tool is advantaged by its simple structure, lower inertia and bigger workspace. In the kinematics analyses, several kinematics performance evaluation indices of the machine tool are proposed and discussed, and the global kinematics performance evaluation atlases are given. In the parameters optimization process, considering the assembly technique, a design scheme of the 5-DOF gasbag polishing machine tool is given to own better kinematics performance based on the proposed statistics parameters optimization method, and the global linear isotropic performance index is 0.5, the global rotational isotropic performance index is 0.5, the global linear velocity transmission performance index is 1.012 3 m/s in the case of unit input matrix, the global rotational velocity transmission performance index is 0.102 7 rad/s in the case of unit input matrix, and the workspace volume is 1. The proposed research provides the basis for applications of the novel 5-DOF gasbag polishing machine tool, which can be applied to the modern industrial fields requiring machines with lower inertia, better kinematics transmission performance and better technological efficiency. 相似文献
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王李华 《机械设计与制造工程》2012,(4):40-42,46
少自由度并联机构应用于机床上时要求具有较好的承载能力,而其承载能力与机构的雅可比矩阵密切相关,应用机构学理论求出其力雅可比矩阵,定义承载能力性能指标,得出了该指标在工作空间内的分布情况,并分析了局部承载能力性能指标与结构参数之间的关系,为该型并联机构的设计与开发提供了依据。 相似文献
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王李华 《中国制造业信息化》2012,41(7):40-42,46
少自由度并联机构应用于机床上时要求具有较好的承载能力,而其承载能力与机构的雅可比矩阵密切相关,应用机构学理论求出其力雅可比矩阵,定义承载能力性能指标,得出了该指标在工作空间内的分布情况,并分析了局部承载能力性能指标与结构参数之间的关系,为该型并联机构的设计与开发提供了依据。 相似文献
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为实现多向3D打印,设计了一种新型五自由度3D打印并联机器人,该机器人具有两个转动自由度和三个平动自由度,其特点是采用铰接的动平台以获得大的工作空间。根据建立的运动学模型,计算了该机器人机构的运动学反解,分析了定姿态位置工作空间和定位置姿态工作空间,用螺旋理论方法建立了速度雅可比矩阵,在此基础上分析了五自由度3D打印并联机器人的奇异性、灵巧性,并进行了运动仿真分析。研究结果表明,所设计的五自由度3D打印并联机器人具有大的位置工作空间和姿态工作空间,该机器人在工作空间内存在奇异位置,通过添加冗余驱动后可以消除奇异位置,并且具有良好的灵巧性,适合多向3D打印。 相似文献
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提出了一种通用3-RPS并联机构,其动平台、定平台为相似的任意三角形,且转动副轴线垂直于定平台中心与顶点的连线,基于该机构设计了一种新型碟式太阳能聚光器。采用封闭矢量法求得机构的运动学位置逆解,并以此为基础,运用螺旋理论分析机构输入与输出的速度映射关系,建立了机构的雅可比矩阵。以全域灵巧度、全域刚度性能及全域承载能力为优化指标,利用遗传算法对机构的结构参数进行优化设计,确定了定平台半径,借助性能图谱法定量地对比分析了优化前后各性能指标在可达工作空间内的分布情况,并采用ANSYS软件对优化前后机构进行静力学验证分析,结果表明:新型碟式太阳能跟踪装置的定平台半径为860 mm时,其灵巧度、刚度及承载能力等均有不同程度的提高。 相似文献
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Jing Shi Yuhan Wang Gang Zhang Han Ding 《The International Journal of Advanced Manufacturing Technology》2013,66(9-12):1879-1889
Friction stir welding (FSW) has recently emerged as a solid-joining technology for high-strength aluminum alloys and light metal welding. The large axial force to be maintained between the welding tool and workpiece is the primary requirement of FSW process, which has also been a great obstacle to the design and application of FSW in manufacturing. Further complicating the issue is the need to perform FSW over three-dimensional contours, which requires a mechanism dexterous enough to set the stir pin used in welding to track a predefined trajectory with prescribed poses. Apart from the position specification, the design of a dexterous mechanism to pose the orientation of stir pin is a great challenge. This paper proposed the application of 3-PRS (P, R, and S standing for prismatic, revolute, and spherical joint, respectively) parallel mechanism as a welding tool head and employed it to form a five-axis welding machine tool for FSW. In order to accommodate the orientation capability requirements, the kinematic feature has been analyzed. With the dimensionless treatment of the Jacobian matrix of 3-PRS manipulator, a global condition index is proposed to estimate the kinematic dexterity in the whole orientation workspace. Finally, by means of an optimal design method and performance atlas, optimal designs of the 3-PRS parallel mechanism is carried out. A preferable set of optimized geometric parameters are obtained to achieve a compact and dexterous design, and the optimization results are used in development of a prototype machine for FSW. 相似文献