四轴视觉坐标测量系统的设计与应用研究

Design and Application of the Four-axis Vision Coordinate Measuring System for Film Cooling Holes

针对涡轮叶片气膜孔的几何参数测量难题,基于工业影像测头与多轴运动机构相结合的设计思想,设计并研制了一套新型的四轴视觉坐标测量系统,由工业影像测头、三坐标测量机、回转工作台和叶片定位工装等集成在一起而构成。在应用过程中,三坐标测量机和回转工作台分别用于实现工业影像测头和被测叶片的运动轨迹,而后由工业影像测头采集被测气膜孔的正焦图像并将图像数据转化到叶片设计坐标系中,从而获得其孔径以及孔心的三维坐标。最后,应用该测量系统对被测叶片前缘部位上的目标气膜孔进行了10次等精度重复测量实验,孔径的重复性测量精度≤±10μm,孔心坐标的重复性测量精度均≤±15μm,然后对一列12个气膜孔逐个测量,验证了该测量系统的可行性与功能实现。

For the difficulties in geometrical parameters measurement of those film cooling holes on turbine blades,a new-type four-axis vision coordinate measuring system based on the design concept of combination of industrial camera and multi-axis motion mechanism was established in the paper,which was integrated by an industrial camera,coordinate measuring machine,turntable and special fixture of blade,etc.In the application procedure,coordinate measuring machine was used to realize the moving track of the industrial camera,while turntable to realize the rotation of the measured blade.And then,the focused image data collected by the camera were transformed from the image coordinate system to the blade coordinate system,in which the diameter and 3 D coordinates of the measured hole would be derived.Finally,the target hole on the leading edge of a turbine blade was measured 10 times by the system,in which the repeatability accuracy of the diameter and 3 D coordinates were smaller than±10μm and±15μm respectively.Also,a row of film cooling holes on the blade were measured to derive their parameters,which verified the feasibility and functions of the system.