工程设计学报2018，Vol.25Issue(1)：27-34,8.DOI:10.3785/j.issn.1006-754X.2018.01.004
基于视觉辅助定位的机械臂运动学参数辨识研究
Research on the kinematic parameter identification of robot arm based on the assistant location by stereo vision
摘要
Abstract
The kinematic parameter identification technique of robot arm is effective for enhancing the absolute positioning accuracy.For the low efficiency of the general calibration methods based on planar constraints,which data can only be captured by manual teaching method,an automatic method was proposed for the kinematic parameter identification of the robot arm with the help of a stereo vision system to locate the constraint planes.In order to remedy the limitation of the common field range of two industrial cameras,three target spots were attached to each constraint plane,so the location of each constraint plane could be equivalent to locate their target spots cor-respondingly.The binocular stereo vision system extracted the center of target spots and then matched them respectively,so that the 3D position information of each target spot in the base co-ordinate system of the robot arm was calculated.Meanwhile,a target coordinate system was built to plan the constraint points according to a certain rule.To enhance the calibration precision fur-ther,an error model based on two planes perpendicular to each other was proposed,then a set of nominal vectors of each plane were calculated by three non-collinear constraint points and the dot product of each pair of nominal vector was zero,namely,there existed an extra restraint in the error model.Then a probe fixed to the end flange of robot arm was used to touch two perpendicu-lar constraint planes automatically,and the actual values of all kinematic parameters could be i-dentified by the improved least squares.Experiments showed that the absolute positioning accura-cy of the robot arm was enhanced from 1.234 mm to 0.453 mm after modifying the kinematic pa-rameters based on the proposed error model.The proposed method realizes automatic measure-ment of data,and highly increases the efficiency of robot arm calibration,and provides a reference for mass calibration,which has great significance of engineering.关键词
机械臂/运动学标定/平面约束/双目视觉/辅助定位Key words
robot arm/kinematic calibration/planar constraint/stereo vision/assistant location分类
信息技术与安全科学引用本文复制引用
王晨学,平雪良,徐超..基于视觉辅助定位的机械臂运动学参数辨识研究[J].工程设计学报,2018,25(1):27-34,8.基金项目
国家自然科学基金资助项目(61305016) （61305016）
江苏省科技重点支撑计划项目(BE2013003-3) （BE2013003-3）
