基于空间直线约束的焊接机器人手眼标定

Hand-eye calibration of welding robot based on the constraint of spatial line

关键词:  手眼标定  线结构光传感器  直线约束

Key words:  hand-eye calibration  line structured light sensor  linear constraint

摘要:

视觉传感器与焊接机器人的标定是焊接智能化应用中的重要问题，针对末端夹持线结构光传感器的焊接机器人，提出了一种基于空间直线约束的手眼标定方法.首先任意变换机器人位姿使线结构光传感器投射出的光平面与标定模板相交，然后通过特征点提取算法提取出线结构光与直线的交点，并基于直线约束建立了非线性优化模型，最后结合罚函数法与改进的Powell算法同时求解传感器位置与方向参数.基于上述方法进行了一系列试验，结果表明，该方法通用性强，适合现场标定，有效的提高了标定精度，标定精度在0.2 mm以内.

Abstract:

The calibration of vision sensor and welding robot is essential in the application of intelligent robot. In this article, to solve the hand-eye calibration of a welding robot holding a line structured light sensor, a method based on a spatial straight line is proposed. Firstly, the robot is required to manipulate randomly its end-effector so that the light plane projected by the line structured light sensor could intersect the calibration template at different configurations. Then the characteristic point extraction algorithm is used to extract the intersection point of the line structure light and the straight line. And a nonlinear optimization model is established based on the linear constraint. Finally, the penalty function method and the advanced Powell algorithm are used to solve the position and direction parameters simultaneously. Based on the above method, a series of experiments is carried out and the experimental results show that the method is versatile and suitable for on-site calibration, which effectively improves the calibration accuracy. The calibration accuracy is within 0.2 mm.