摘要
机器人柔性坐标测量系统能够实现大型工件尺寸在线快速测量,是自动化生产线的关键质量监控设备。现场校准技术是柔性坐标测量系统的关键技术之一,校准精度直接影响系统测量精度。现场精确建立机器人末端工具坐标系与视觉传感器坐标系形成的手眼关系、机器人运动学模型参数以及机器人基坐标系是现场校准的主要内容。通过设计中间靶标,利用激光跟踪仪直接测量的方法建立手眼关系,其转换精度不受机器人运动学误差影响;设立校准球体,实现基于距离不变模型的连杆参数现场快速校准;根据机器人正向运动学模型和激光跟踪仪的测量,利用基于奇异值分解的配准方法求解转换矩阵,高精度地建立机器人基坐标系。经过激光跟踪仪一次校准后,测量系统可利用基准球体实现机器人快速在线校准,减小模型参数变化对测量系统精度的影响。试验证明,校准后的测量系统整体误差低于0.2mm。
Robot flexible coordinate measurement system can fulfill rapid online measurement of large workpieces.It is an important quality monitoring equipment on the automatic production line.Field calibration technology is one of the key technologies of the flexible coordinate measurement system.The calibration accuracy affects the measurement system precision directly.The hand-eye relationship between the robot flange coordinate and the vision sensor coordinate,the parameters calibration of the robot kinematics model and the establishment of the robot base coordinate system are the three main contents of the field calibration.The hand-eye relationship is established directly by using laser tracking and intermediate targets.Thus transformation accuracy is irrelevant to the robot＇s kinematics error.The fast calibration of link parameters based on constant distance model is achieved by fixed calibration spheres.According to robot kinematics model and measuring results of laser tracker,transformation matrix is solved through registration based on singular value decomposition.Robot coordinate system is established precisely.After primary calibration by using the laser tracker,rapid online calibration can be realized with the reference sphere so that the influence of the model parameter variations on the measurement system can be decreased.The experiments show that the error of the whole measurement system is smaller than 0.2 mm after calibration.
出处
《机械工程学报》
EI
CAS
CSCD
北大核心
2010年第18期1-6,共6页
Journal of Mechanical Engineering
基金
国家自然科学基金(50805105)
国家高技术研究发展计划(863计划
2008AA042407)资助项目
关键词
工业机器人
视觉测量
现场校准
手眼关系
奇异值分解
基准球
Industrial robot Vision measurement Field calibration Hand-eye relationship Singular value decomposition Reference sphere
