基于蒙特卡洛模拟的6-UPS并联机构的误差分析

Error Analysis of 6-UPS Parallel Mechanisms Based on Monte Carlo Simulation

根据6-UPS并联机构逆运动学模型,通过微分变换,构建了动平台位姿误差模型,由误差模型可知:动平台位姿误差来源于6个支杆长度误差和12个铰链中心的位置误差,共42个误差项。还建立了轴承间隙对万向节中心位置和复合球铰中心位置影响的随机误差模型,利用蒙特卡洛模拟分析了支杆长度误差和轴承游隙对动平台的位姿误差的影响,结果表明:当支杆长度误差服从均匀分布,铰链中心位置误差服从均匀分布时,动平台位姿误差近似服从正态分布,且动平台位姿对铰链轴承游隙的敏感度大于对支杆长度误差的敏感度。为6-UPS并联机构的误差分析提供了一种方法。

According to the inverse kinematics model of 6-UPS parallel mechanism,an error model about moving platform＇s pose is built through differential transformation.It shows that.：position and orientation errors of the moving platform come from 6 stria length errors and 12joints＇ centerposition errors,a total of 42 errors term.Furthermore,the random error model of the universal joint center position errors and the composite ball joint center position error affected by the bearing clearance is also established.An error analysis of the impact of strut length errors and the impact of the bearing clearance is presented based on a Monte Carlo simulation.The results show that：when strut length errors and joint center position errors are all subject to uniform distribution,the moving platform position and orientation errors are similar to normal distribution.And the impact of the bearing clearance is bigger than impact of the strut length errors.It provides a way to analyze the errors of 6-UPS parallel mechanism.