具有远近视距引导的机械臂多工位精确对准技术

A Multi-station Precise Alignment Technique of Robotic Arms Guided by Far-Near-Sight Vision System

为提升机械臂系统对环境的感知能力,针对机械臂多工位精确对准问题,提出了一种具有远近视距引导的机械臂多工位对准技术。首先构造具有远近视距的两目视觉配置,并与机械臂构成Eye-in-hand视觉反馈系统。然后标定两目视觉的内外参数和手眼关系变换矩阵。通过离线先验局部对准方式,建立各工位的任务表。提出了三阶段对准策略,即多工位作业起始位姿获取、全局相机的初定位和局域相机的精对准,使得机械臂能在多个工位下实现末端工具与目标的精确对准。通过多位置孔轴对准实验验证了本文方法的可行性。单个孔位重复对准标准差角度不超过0.015°,位置不超过0.078 mm,三阶段对准实验结果表明,角度误差小于0.05°,位置误差小于0.17 mm。

To improve the robotic arm system’s ability of perceiving the environment,a multi-station precise alignment technique of robotic arms guided by far-near-sight vision system is proposed.First,a configuration is built with one far-sight camera and one near-sight camera,and an eye-in-hand robotic arm is built up.Second,intrinsic and extrinsic parameters of the vision system and the transformation relationship between the vision system and the robotic arm are calibrated and a task table is established by a local priori alignment method.Third,a three-stage alignment strategy is proposed,i.e.,the acquisition of the starting pose of the multi-station operation,the initial positioning of the global camera,and the fine alignment of the local camera.Thus,the robotic arm can achieve precise alignment between the end tool and targets in multiple stations.The feasibility of our method is verified experimentally.The angle’s standard deviation is below 0.015°by 50times repeated single-station pin-hole alignment,and the position standard deviation is below 0.078 mm.The three-stage alignment experiment in multi-stations alignment shows that the angle error is below 0.05°and the position error below 0.17 mm.