基于全局空间控制的高精度柔性视觉测量系统研究

针对传统机器人视觉测量系统中测量精度受机器人绝对定位精度限制的问题,构建了基于全局空间控制的高精度柔性视觉测量系统并研究其标定技术。通过全局空间测量定位系统实现机器人末端工具的高精度实时控制,可以突破机器人自身定位精度的限制,充分发挥其高度柔性的运动特性。为实现系统高精度测量,提出一种基于单应性矩阵的视觉传感器外参标定方法,该方法仅需对所设计的平面靶标进行一次成像,结合激光跟踪仪进行坐标转换即可实现传感器坐标系与外部参考坐标系之间坐标转换关系的精确标定。实验结果表明,基于全局空间控制的机器人视觉测量系统在其工作空间中距离测量精度优于0.2/mm,较传统的机器人视觉测量系统得到显著提高。

High-precision flexible visual measurement system based on global space control

As the measuring accuracy of traditional robot visual measurement system is limited by the robot absolute positioning accuracy, a new high-precision robot vision measurement system based on the workspace Measurement and Positioning System was developed and its calibration technology was researched. In this system, the robot end-effector can be positioned precisely by the workspace Measurement and Positioning System in real time, freeing its positioning accuracy from the robot accuracy. The system only makes use of the high flexibility and automation of the robot. In order to realize the high-precision measurement, a new calibration method of calibrating the exterior parameters of the visual sensor based on the homography matrix was proposed. In this method, a calibration target was designed and imaged by the visual sensor. With the aid of laser tracker for coordinate transformation, the external parameters can be easily determined with only one image of the calibration target. The verified experiment shows that the distance measuring accuracy over the robot working volume is superior to 0.2/mm, which has been improved significantly compared with the traditional robot visual system.