Research On Measurement Planning Of Laser-scanning And Adaptive Geometric Modification For Aero-engine Blades

Wide-Chord hollow blades are one of the key parts of aero-engine with heigh thrust-weight ratio. The machining quality of blades have a significant influence on the performance of aero-engine. At the present days, a compound manufacturing process is getting great attention, which firstly using superplastic forming to get the near-net-shaped rough-workpiece and then using adaptive numerical control machining to cut the leading edges, trailing edges and roots areas. Therefore, the adaptive machining has become the key technique of wide-chord hollow blades machining process.Based on the compound manufacturing process of wide-chord hollow blades, a series of key techniques of adaptive numerical control machining include laser-scanning measurement planning, registration between rough-workpiece point cloud data and the CAD model, geometric modification of blades leading and trailing edge are studied and a laser-scanning measurement planning and daptive geometric modification for aero-engine blades system is developed. The main research contents and innovative points are summarized as follows:1) Laser-scanning measurement planning technique is studied. Research on the method of measuring points distribution; It proposes a measuring-head pose planning algorithm based on K-Means, which calculates the least measuring-head poses that required for measuring all the measuring points; Study on the generation of measuring path based on characteristics of laser-scanning and ordering of measuring points.2) Registration between rough-workpiece point cloud data and the CAD model data is studied. It presents a registration method on the basis of basin and dorsal parts.3) A new algorithm of geometric modification of blade leading and trailing edge is proposed. This algorithm is based on feasible regions obtained from tolerance and allowance analysis. Firstly, the rotation adjustment component was obtained by model registration under the margin constraint; Secondly, the translation adjustment component is optimized by using the feasible regions; Finally, the contour line of the leading and trailing edge is generated after the adjustment.4) On the basis of the above key algorithms and techniques, a laser-scanning measurement planning and adaptive geometric modification for aero-engine blades system is developed on UG platform. The experiment shows that the related theories of this thesis are correct and the software system is practical.