Study On Adaptive Positioning And Repairing Method Of Blade Based On Vision Measurement

Aero engine blades are important core components of aero engines.Because of the bad working environment,they are easy to be damaged,which affect the flight safety.It is more economical to repair the damaged engine blades because of the high cost of replacing blades.The original model is difficult to obtain in the process of blade repair,and the blade will creep after use,which is difficult to apply to the blade to be repaired.At the same time,the blade surface shape is complex,and the damage forms are various.It is difficult to realize the precise positioning in the CNC machine tool,which is an urgent technical problem to be solved in the research of blade adaptive positioning repair process.For this reason,this paper studies a method for adaptive positioning and repair of blades based on vision measurement to achieve automatic blade repair.The main research work of the dissertation includes:1.Combining the basic principles of binocular stereo vision to build a speckle vision measurement system,a method of blade point cloud measurement based on speckle vision measurement is proposed,which realizes the measurement of non-contact blade point cloud data with strong randomness,moderate number of point clouds and less noise points.2.The method of model reconstruction of damaged blade point cloud data is studied.The boundary points are extracted according to the curvature variable step length.On this basis,Bspline curve and surface fitting and surface extension are carried out to complete the damaged blade configuration,which can provide the model basis for the adaptive positioning and repair of blades,and the measurement method and configuration method are verified by experiments.3.In view of the complex shape and various damage forms of curved blade,traditional fixture positioning can not meet the positioning requirements of its reduced material complex shape,an adaptive positioning method of blade based on speckle vision measurement is proposed.The adaptive positioning model is solved according to the position and attitude relationship of each positioning coordinate system to realize the adaptive positioning of the blade under the underpositioning clamping,and the standard gauge block is used for experimental verification.4.The path planning method of blade adaptive positioning and repair path is studied.According to the measurement of blade shape and position information by vision measurement system,the environment of UG NX software is used to generate adaptive positioning and repair path planning and NC machining code generation,and then the repair path is simulated by simulation machining software.On this basis,a blade adaptive positioning repair experiment was performed,which has a good repair effect under the existing experimental conditions.