Approximate Stiffness Modelling and Stiffness Defect Identification for a Heavy-load Parallel Manipulator
Approximate Stiffness Modelling and Stiffness Defect Identification for a Heavy-load Parallel Manipulator
复制标题
重载并联机构的近似刚度建模与刚度缺陷识别
DOI：
10.1017/s0263574718001492
复制
发表时间：
2019-06-01
期刊：
影响因子：
2.7
通讯作者：
Fan, Shouwen
中科院分区：
文献类型：
--
作者：
Fan, Shuai;Fan, Shouwen
并联机器人作为机床使用时，其刚度是影响产品质量的重要因素。本文提出了一种重载并联机器人的整体近似刚度模型，该模型考虑了驱动器刚度、关节间隙、关节接触变形和肢体变形的影响。基于虚功原理和引入的修正参数，提出的总柔度矩阵成功地将四个因素统一表达。为了得到总体柔度矩阵，给出了关节间隙、关节接触变形和肢体变形的近似刚度模型。此外，通过结合包含随机不确定性的统计模拟和提出的近似刚度模型作为每个随机变量幅值的基础，还提出了一种基于期望轨迹和外载荷的刚度缺陷识别方法，使估计更加准确和可靠。最后，以1PU+3UPS并联机器人为例，验证了所提出的刚度模型和缺陷识别方法的实用性。修改缺陷部件的结构参数后，样机的刚度有了显著的提高。
When using parallel manipulators as machine tools, their stiffness is an important factor in the quality of the produced products. This paper presents an overall approximate stiffness model for a heavy-load parallel manipulator, which considers the effects of actuator stiffness, joint clearance, joint contact deformation, and limb deformation. Based on the principle of virtual work and the introduced modified parameters, the proposed overall compliance matrix successfully takes four factors into a unified expression. To obtain the overall compliance matrix, the approximate stiffness models of the joint clearance, joint contact deformation, and limb deformation are given. In addition, by combining the statistical simulation including the random uncertainties and the proposed approximate stiffness models as the basis of the magnitudes for each random variable, an approach based on the expected trajectory and external load is also proposed for stiffness defect identification such that the estimation is more accurate and reliable. Finally, a numerical example of the 1PU+3UPS parallel manipulator and a discussion are presented to demonstrate the practicability of the proposed stiffness model and defect identification approach. After modifying the structure parameters of the defective components, the prototype experiences a significant stiffness improvement.