气膜冷却孔空间位置的五轴视觉检测技术研究

Study on five-axis vision measuring method of spatial coordinates of film cooling holes

为了使所研制的五轴视觉测量系统实现对气膜冷却孔空间位置的检测功能,开展了坐标系建立与数据传递方法研究,将孔心坐标的测量数据由图像空间转换到叶片空间。在应用过程中,建立了包含多个坐标系的数学模型,并确立了测量数据在各个坐标系间的传递关系,从而将冷却孔孔心的二维图像数据转化成三维物理测量数据,并最终转换到叶片设计坐标系中。为了验证该方法的可行性与功能实现,选取某高压涡轮叶片作为被测对象,首先对其前缘部位上的目标孔进行了孔心坐标的10次等精度重复测量实验,孔心坐标分量x、y和z的重复性测量精度均≤±15μm,然后对一列12个冷却孔逐个进行了测量。实验结果表明,所提出的五轴视觉检测方法,可以完成冷却孔空间位置的检测任务,从而为后续与理论数据进行比对并做出评价奠定了基础。

To inspect the spatial coordinates of film cooling holes using the five-axis vision measuring system set up in the paper,methods of coordinate systems establishment and measuring data conversion were studied,which could be used to translate the measuring data of hole center from the image space to the blade space.In the application,mathematical model containing multiple coordinate systems were established,as well as the translating relationship among them.In this way,the 2 D image data of the measured hole center could be converted to 3 D physical data,and then transformed into the design coordinate system of blade.To verify the feasibility and function of the method proposed,the target hole on the leading edge of a turbine blade was measured 10 times by the system,in which the repeatability accuracy of x,y and z of the hole center were all smaller than±15μm respectively.Also,a row of film cooling holes on the blade were inspected to derive their spatial parameters.As the experimental results showed,the five-axis measuring method put forward could be utilized to fulfill the inspecting assignment of the distributions of film cooling holes,which could serve as a foundation for the subsequent comparison with the design data and quality evaluation.