基于单维拉线测量系统的码垛机器人定位误差分析及运动学标定

Positioning Error Analysis and Kinematic Calibration of Robot Palletizer Based on One-Dimensional Cable Measurement System

以四自由度码垛机器人为研究对象,基于单维拉线测量系统对该机器人的运动学标定方法进行了研究.采用环路增量法构造了码垛机器人平行四连杆的误差模型,并建立了带关节变量比例系数的运动学误差模型,从而对关节传动误差进行补偿.通过对影响机器人末端位置精度的几何误差参数进行敏感性分析,将几何误差源简化为11项,可有效提高辨识效率.结合单维拉线测量系统的特点,建立了末端运动误差与几何误差源的映射关系,进而提出了一种基于距离测量的参数辨识模型.通过计算机仿真和标定试验对该方法的有效性进行了验证.试验结果表明,标定后码垛机器人位置误差3?值由11.73,mm减小至1.79,mm,运动精度提升84.7%,.

An example of a 4-DOF robot palletizer was applied to study the kinematic calibration method based on one-dimensional cable measurement system.The parallel four-connecting rods error model of robot palletizer was built by loop incremental method,and the kinematic error model with joint variable proportionality was established,which could compensate the error of joint transmission.The number of geometric error sources was reduced to 11 by analyzing the sensitivities of geometric error parameters to the position accuracy of robot,which could promote the efficiency of identification.The parameter identification model based on distance-measurement was proposed by building the mapping of end motion error and geometric error sources according to the characteristics of onedimensional cable measurement system.The validity of the method is verified by computer simulation and calibration experiment.The experiment results show that the 3,sigma value of robot position error decreased from 11.73 mm to 1.79 mm after calibration,that is increased by 84.7%.