基于无标定视觉伺服的激光标记自动跟踪视频引伸计控制系统设计

Design of Control System of a Laser Mark Automatic Tracking Video Extensometer Based on Uncalibrated Visual Servoing

本控制系统采用图像雅克比矩阵在线辨识的方法,建立了激光标记与试件标记的实际距离,即激光标记的跟踪位移量到图像空间跟踪位移量的映射关系,不仅避免现有视频引伸计的摄像机标定环节,而且实现了激光标记对试件标记的精密全程跟踪。通过低碳钢和铸铁的拉伸实验,分别实现跟踪精度1.8μm/10mm和0.9μm/2.5mm,验证了设计的控制系统的有效性和精确性。

This control system uses image Jacobian matrix online identification method to establish the actual distance between laser mark and specimen mark,i.e.the mapping from laser mark tracking displacement to image space tracking displacement,which not only avoids camera calibration link of existing video extensometer,but also realizes whole process precision tracking of specimen mark by laser mark.In low-carbon steel and cast iron tensile tests,tracking precision 1.8μm/10mm and 0.9μm/2.5mm have been achieved respectively,which verifies the validity and precision of the designed control system.