高速并联机械手静动态特性分析及优化设计

Static / Dynamic Analysis and Optimal Design of a High-Speed Parallel Manipulator

以一种可实现选择顺应性装配机器手臂(SCARA)运动的4自由度高速并联机械手(以下简称Cross-IV机械手)为研究对象,将运动学理论与有限元分析相融合,提出一种全域参数化有限元模型的建模策略和结构参数的优化设计方法.首先以运动学逆解分析为基础,利用有限元软件Ansys的编程语言(APDL)实现机械手在位姿、尺寸和结构参数变化时整机有限元模型的快速创建;然后利用参数化有限元模型提出一种分析整机系统全域静刚度和低阶固有频率分布规律的循环建模策略,进而获得全域内性能最差位形.最后定义一种评价机械手机构动态特性的性能指标,以一组尺度参数为例,利用正交试验,深入分析结构参数对系统动态性能的影响,进而综合得到一组最优结构参数.

By combining the finite element analysis with the kinematical theory,a modeling strategy of the global parametric finite element model and an optimal design of structural parameters are proposed for a 4-DOF high-speed parallel manipulator which can realize SCARA（ Selective Compliance Assembly Robot Arm） motion. First,based on the inverse kinematic analysis of the Cross-IV manipulator,the finite element model of the manipulator under different conditions of configurations,dimensions and structures can be rapidly constructed by means of the Ansys programming language APDL. Next,by using the parametric finite element model,a circular modeling strategy is presented to evaluate both the global static stiffness and the low-order natural frequency distribution of the whole machine,and the configuration of the worst performance is obtained. Finally,a novel performance index is defined to estimate the dynamic characteristics of the manipulator,and the effect of structural parameters on the dynamic performance of the system is deeply analyzed through the orthogonal experiments of a set of scale parameters.Thus,a set of optimal structural parameters are obtained.