Digital Template System for Measuring Turbine Blade Forging and Its Calibration Method

Because of complex profile and large size, the measurement of turbine blade is complicated and difficult. A digital template measurement system is developed, which is composed of two laser scanners, two linear motion modules, one turntable and the developed blade measure & analysis software. In order to achieve high precision, the specific calibration method is proposed for each part, such as the laser scanner, the motion direction of scanners, the relative pose between scanners, and the axis of the rotation module. In the first and second calibration stage, only the calibration board is adopted. After the camera is calibrated, the laser plane and the motion direction of scanner are determined with PnP method. In the third and fourth calibration state, the sphere is adopted as the feature to determine the parameters. In the experimental section, we analyze the precision of calibrated system and introduce the application of blade measurement.