Adaptive Positioning Repair Method for Aero-Engine Blades by Using Speckle Vision Measurement

The repair of damaged aero-engine blades has an extremely high economic value. Due to the complexity of the blade surface and various kinds of deformation during the lifetime, blade positioning in the repair process has always been one of the key problems in the aviation industry. In this study, a method of blade self-adaptive positioning repair method based on speckle vision measurement is proposed. Firstly, a speckle vision measurement system is established to measure the speckles coated on the damaged blade surface to obtain its surface point cloud. Meanwhile, the coordinates of the reference points on the fixture are obtained to build the relative pose model between the blade and the fixture. Secondly, through the solution of posture relations among the mark point coordinate system, measuring camera coordinate system, probe coordinate system, and machine coordinate system, the self-adaptive positioning of the under-positioning clamping blade in the machine coordinate system is achieved. Then based on the positioning model, the machining repair parameters are selected reasonably to complete the CNC (Computer numerical control) path planning of tool repair. Finally, the DMU five-axis numerical control center was used to carry out adaptive positioning repair experiments on the damaged blades. The experimental results showed that this method could achieve satisfying repair effect in under positioning clamping, and provide a new method for repairing damaged aero-engine blades.