精密装配用并联机器人标定及机构误差分析

Calibration and mechanical error analysis of a parallel manipulator used for a precise assembly

摘要:

为了提高手机摄像头的装配精度,设计开发一款用于精密装配的小型并联机器人,并对机器人进行标定以及机构误差分析．用数值方法推导机器人的正逆运动学模型和误差模型,并探讨机器人运动学模型和误差补偿模型衔接的问题;设计在桥式三座标测量机上进行测量标定的方法,并对机器人进行标定实验;从机构角度对机器人的间隙误差来源进行分析,分析机器人构型对间隙误差的约束,并对机器人进行重复定位精度测试．经过标定及机构误差控制,机器人位姿坐标的最大位移误差由0.345 9 mm降为0.012 1 mm,最大转角误差由0.007 3 rad降为0.001 1 rad,重复定位精度为0.004 8 mm．实验结果表明该标定方法及机构误差分析方法能有效提高机器人的精度．

Abstract:

To improve the assembly precision of mobile phone camera, a small-sized parallel manipulator (SSPM) used for precise assembly was developed, and a calibration test and mechanical error analysis were conducted. First, an error model and the forward-inverse kenametic model were derived using numerical method, and the connection problem between the error model and the kenametic model was studied. Second, a calibration procedure was designed and a calibration test was conducted on coordinate measuring machine (CMM). Finally, an analysis on the error sources of SSPM was conducted from the mechanical view, the effect of SSPM’s structure on the gap error was analyzed, and a repeatability test of SSPM was conducted to represent the gap error. After calibration and mechanical error control, the maximum displacement error decreases from 0.345 9 mm to 0.012 1 mm, the maximum angular error decreases from 0.007 3 rad to 0.001 1 rad, and the repeatability of SSPM is 0.004 8 mm. Experimental results show that the calibration and mechanical error control method on SSPM can effectively improve the accuracy of SSPM.