A Variable Curvature Adaptive Trajectory Planning Method and Experiment for Robotic Belt Grinding of Blisk Surface

Abstract

The blisk is a significant part of the new generation of an aero-engine, and its processing accuracy and surface integrity seriously affect the aerodynamic performance and service performance of the aero-engine. Robotic belt grinding (RBG) is an essential technology to guarantee the final accuracy of the blisk. To solve the problems of difficult trajectory planning, poor accuracy and low efficiency in the process of RBG with blisk surface, a variable curvature adaptive trajectory planning (VCATP) method is proposed. Firstly, the NURBS method is used to reconstruct the blisk surface. Then, considering the variable curvature characteristics of the blisk surface, an improved step-length(SL) and row-spacing(RS) calculation method is proposed according to the equal chord-height error method and constant scallop-height method, which can get all the grinding points(GPs) on the surface of blisk. Finally, the proposed VCATP method also can be verified by relevant experiments. And the experimental results show the average surface roughness Ra of blisk profile reaches 0.31$\mu$m, the machining efficiency is improved by 25%, and the profile accuracy is greatly improved.