三平移(3-PRRP^(4R))并联减振机构的设计与刚度分析  

Design and stiffness analysis of three-dimensional(3-PRRP^(4R)) parallel vibration reduction mechanism

作　　者：牛军川[1,2] 张福亮[1] 

机构地区：[1]山东大学机械工程学院,济南250061 [2]山东大学高效洁净机械制造教育部重点实验室,济南250061

出　　处：《农业工程学报》2016年第7期58-65,共8页Transactions of the Chinese Society of Agricultural Engineering

基　　金：国家自然科学基金(51275275);山东省优秀中青年科学家科研奖励基金(BS2010ZZ006)

摘　　要：为有效解决工农业生产中的多维振动问题,针对一种3-PRC机构的不足进行了优化设计,得到了一种3-PRRP4R机构。与传统的3-PRC机构相比,3-PRRP4R机构具有更好的运动学和力学性能。建立了3-PRRP4R机构的运动学模型,运用齐次坐标变换法对机构的运动学进行了分析,得到了机构的雅可比矩阵和工作空间,与3-PRC机构相比,3-PRRP4R机构的工作空间具有更好的对称性。在Adams软件中仿真验证了(4R)^机构比圆柱副C具有更好的力学性能。以3-PRRP4R机构为主体,通过在主动副处添加弹簧阻尼,构建了多维减振平台,基于虚功原理推导了系统的静力学平衡方程,引入了系统的等效刚度,得到了系统等效刚度在工作空间内的分布规律。该研究可为并联机构的优化设计、等效刚度分析、动力学分析和多维减振应用等提供参考。In order to solve the problems of multi-dimensional vibration in industry and agriculture effectively, the optimization design of the 3-PRC parallel mechanism is carried out for improving its kinematic performances and mechanical properties. A classic 3-PRC parallel mechanism with 3 translational degrees of freedom (DOF) has some defects such as asymmetry, and low mobility. Therefore, for eliminating these defects, the 3-PRC parallel mechanism is upgraded into a novel 3-PRRP4Rparallel mechanism by adopting some optimal measures. Firstly, change the cylindrical pair into a revolute one and apply a 4R structure which includes 4 revolute pairs in the mechanism so as to make the parallel mechanism move more smoothly. Additionally, change the arrangement form of sub-chains from square to equilateral triangle, which makes the force distributed more homogeneously on platforms. Finally, change the position relationship between the sliding pair and the revolute pair, and eliminate the unwanted additional torque. After the improvement of the mechanism, based on the screw theory, the degree of freedom and the motion form of the 3-PRRP4R parallel mechanism are analyzed. The result shows that the 3-PRRP4R parallel mechanism is still a 3-DOF translation mechanism which can be used as three-translation vibration reduction platform. Using the homogeneous coordinate transformation method, the kinematics of the 3-PRRP4R parallel mechanism is formulated. The inverse kinematics solution describes the displacement relationship between upper platform and active joints which are on the lower fixed platform. Jacobian matrix, which describes the velocity relationship between upper platform and active joints which are on lower platform, is obtained by the analysis of velocity. Through the coordinate searching method, the workspace of the 3-PRRP4R parallel mechanism is obtained, which has better symmetricity than the classic 3-PRC parallel mechanism. The comparison of the workspaces shows the 3-PRRP4R parallel mechanism is more suitable as

关 键 词：振动 优化 模型 并联机构 多维减振 工作空间 刚度 

分 类 号：TH112[机械工程—机械设计及理论]