并联机构运动学标定的参数可辨识特性研究

项目名称： 并联机构运动学标定的参数可辨识特性研究

项目编号： No.51505279

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 机械、仪表工业

项目作者： 陈根良

作者单位： 上海交通大学

项目金额： 21万元

中文摘要： 末端定位精度是影响机构操作性能的一个重要指标，运动学标定是提高机构绝对定位精度的有效途径。通过运动学参数的可辨识性分析，可以确定影响机构末端定位精度的尺寸误差参数中的独立分量，为运动学标定建模与误差补偿控制提供理论依据。目前，对于串联机构的参数可辨识特性研究已较为成熟，而针对拓扑结构更为复杂的并联机构，由于存在被动关节的协调运动和缺乏误差参数的独立性判别准则，目前尚缺乏有效方法来分析其运动学参数的可辨识特性。.本项目依据并联机构的构型特点，从各运动支链对末端平台的约束偏差分析入手，建立从各个构件尺寸误差到各支链约束误差，再到末端位姿误差的层次化误差映射模型，借助末端位姿误差空间到各支链约束误差子空间的直和分解，在各运动支链内部实现并联机构的尺寸误差独立性判别与运动学参数可辨识性分析，为运动学标定与误差补偿控制提供准确的模型基础，提高并联构型操作装备运动学标定的参数辨识精度。

中文关键词： 并联机构；运动学标定；误差建模；可辨识参数；独立误差参数

英文摘要： Accuracy performance of mechanisms plays an important role in robot manipulations. As an efficient and economical approach, kinematic calibration can significantly improve the absolute positioning accuracy of robot manipulators. Generally, robot calibration can be divided into four consequent procedures: modeling, measurement, identification and compensation, among which the identifiability analysis of geometric parameters serves as a fundamental issue. During the past decades, many researchers have made their contributions to this problem for serial robots manipulators and several systematic approaches have been proposed to determine the identifiable parameters. However, for parallel manipulators, the identifiability analysis of the geometric parameters is still far from being complete due to the complexity of their structural topology. .According to the duality between parallel manipulators and their serial counterparts, this proposal presents a hierarchical strategy for the geometrical error modeling and kinematic-parameter identifiability analysis of parallel manipulators. The concept of constraint errors is proposed for the limbs to describe the influences of the links'geometrical errors on the limbs' constraints to the moving platform. The constraint errors of different limbs are independent from each other and can be considered as the direct causes of the moving platform’s pose error due to links' geometrical ones. Hence, the pose error of the moving platform can be uniquely distributed into the limbs by taking advantage of the direct-sum decomposition of the end-effector's error space into the limbs' sub-ones. As a consequence, the identifiability analysis of the whole parallel manipulator can be transformed to the ones for determining the independent parameters that influence the constraint errors in individual limbs. Therefore, existing methods for serial robots can be employed to solve the identifiability problem of parallel manipulators. Using the proposed method, a complete and minimal error model can be obtained for the kinematic calibration of parallel manipulators, which can improve the identification accuracy of the geometric parameters.

英文关键词： parallel manipulator;kinematic calibration;error modeling;identifiable parameters;independent errors