手眼系统中刀具刀头位姿标定与视觉引导

在服务机器人的日常任务中要求机械手抓取不同的目标,且根据目标的放置位姿的不同需要从相应角度进行抓取,但机械手与手持目标的位姿关系往往难以精确和直接地测量。以刀具作为手持目标,利用eye-in-hand手眼系统抓取该目标后,在线标定手眼与手持刀具刀头的位姿关系,首先给出了摄像机调焦前后焦距标定的计算方法,再将调整焦距视为摄像机沿光轴的平移运动,通过调焦前后摄像机获取的两幅图像,标定出刀具在摄像机和机械手坐标系下的位姿,同时给出了刀具刀头到期望加工点的导向矢量计算方法。

Pose calibration and visual guidance of endmost tools in hand-eye system

When service robots provide daily services,different tools may be held by the gripper on the robot arm from a right angle,but it is hard to measure directly and exactly the pose relationship between hand-eye systems and endmost tools.In this paper,we calibrate this relationship by only utilizing a bifocal monocular camera focusing on the eye-in-hand system by three steps.Firstly,we propose a method to calculate the focal length after camera focusing.Secondly,taking camera focusing as the camera translation along the optical axis, we present a method to detect the position and the pose of the endmost tools in the camera and in the manipulator coordinate systems respectively according to the two images captured before and after camera focusing. Meanwhile, a method is given to calculate the direction vector from endmost tools to the expected position.