六自由度机械臂参数校准不确定度评定方法

六自由度机械臂的结构参数校准对其定位精度影响较大, 为了评价其参数化校准效果,采用蒙特卡洛法建立了六自由 度机械臂参数校准不确定度评定模型。 首先, 根据空间坐标系的几何转换关系建立六自由度机械臂结构参数校准模型, 分析 主要误差来源对校准参数的影响,建立各校准参数的不确定度分量的函数关系; 其次, 采用现场校准数据集的抽样统计, 分析 各不确定度分量的概率密度函数,获得真实分布规律; 最后, 采用蒙特卡洛法建立各校准参数的不确定度分量与机械臂模型 之间的数学关系, 通过大规模随机数值模拟, 实现机械臂校准不确定度的评定。 为了验证本文方法的有效性, 利用激光跟踪 仪对六自由度机械臂进行了校准实验。 结果表明, 当采用正则化方法进行机械臂校准时,各坐标轴的相对扩展不确定度分别 优于 0. 542 2% ,1. 325 9% , 0. 015 4% 。

Uncertainty evaluation of calibration model of six DOF robot arm

In this article, the Monte Carlo method is used to evaluate the uncertainty of the robotic arm calibration system. First, this method formulates a model for each variable of the manipulator calibration system. Then, the actual distribution of the input is obtained by establishing the actual data set as the input of the manipulator calibration system. To evaluate the correctness of this method, the main sources of uncertainty in the calibration process are analyzed, and a method based on Monte Carlo uncertainty evaluation is proposed to evaluate the calibration process of the manipulator based on regularization. By using laser tracker as the measurement tool, the method of robot regularization parameter identification is evaluated experimentally. And the uncertainty evaluation of robot calibration is carried out. The results show that the relative expanded uncertainty of each axis is better than 0. 542 2% , 1. 325 9% , and 0. 015 4% , respectively.