【作者】 刘明；

【导师】 邹平；

【作者基本信息】 东北大学 ， 机械电子工程， 2009， 硕士

【摘要】 并联运动学机器(Parallel Kinematics Machine, PKM)是上个世纪90年代中期问世的新型制造装备,相对于传统的串联式机床来说,并联机床具有高刚度、高承载能力、高精度以及重量轻、结构简单等一系列优点,所以它是新一代机床结构的重要发展方向。并联机床的静态和动态特性是评价机床特性的重要指标,他们直接影响到机床的加工精度和被加工零件的加工质量,本文对一种新型的少自由度并联机构——三并联万向工作台,初步研究的基础上,对其静态和动态特性进行了的研究,为整机的改进和发展提供了依据。通过查阅大量的国内外相关文献,本文对并联机床的概念、特点、分类、国内外发展现状和应用等作了简要概述,探讨了并联机构的优缺点和主要发展方向。在此基础上,本文利用相关软件对三并联万向工作台静态和动态特性进行了详细分析,找出工作台的薄弱环节、计算出了工作台的刚度和固有频率等重要参数、并提出了改进的意见。首先用PROE设计工作台的结构,然后将实体模型导入ANSYS中,经过一定的处理后将起转化成需要的有限元模型。在静力学特性分析中,考虑并联工作平台的承受静力时的受力特点,通过应用ANSYS有限元软件对并联工作平台进行了静力分析,得出了整机在不同位姿时的应力应变图,分析了工作台应力分布规律。在静刚度分析中,根据并联机床的静刚度理论,对并联工作台进行了有限元刚度分析,得出了工作台不同位姿时的整机的变形图和刚度值,分析了工作台刚度分布规律和影响因素。最后,运用了有限元的模态分析理论和ANSYS软件中模态分析功能,研究了工作台固有频率和固有振型。更多还原

【Abstract】 Parallel Kinematics Machine (PKM) is a new kind of manufacture equipment comes into the world in the middle of90s. Compared with conventional series machine tool, it is higher rigidity, load-bearing ability and precision, lower weight, simpler structure, and so on. Thus, PKM becomes an important development direction of new type of machine tool. The static and dynamic characteristic of parallel machine tool is one of the most important characteristic of machine tool evaluation. They directly affect the machining accuracy of machine tools and machining processing quality. Based on the preliminary study, the static and dynamic characteristic of a novel parallel mechanism, tripod parallel universal platform, is studied in this paper which can provide causes for the improvement and development.The conception, characteristics and development condition of PKM are summarized, and the advantages, disadvantages and the main developing direction of PMT are discussed. On this basis, the static and dynamic characteristic of the tripod parallel universal platform are analyzed in detail by the use of the relevant software in this paper. Then the weak point of the platform is identified, the stiffness and nature frequency are calculated, and the improvement is proposed.First, the structure of the platform is designed by the used of PROE. Then, the solid model is imported into ANSYS to change it into the needed infinite element model by necessary process. In static mechanical properties analysis, the static characteristic of the parallel platform is analyzed by the used of ANSYS software, considering the characteristics of parallel platform under the static load, to find the stress and strain diagram of the whole platform in different postures, and then to find the stress distribution rules. In the static stiffness analysis, the stiffness finite element analyze of the platform is made based on the theory of the static stiffness of the parallel platform. Then the deformation map and the stiffness value of the whole machine are got in different postures. The stiffness distribution rule and affection factor is analyzed. At last, finite element modal analysis theory and modal analysis functions of ANSYS software are used to study its nature frequency of vibration modes.更多还原