Research on robotic belt grinding method of blisk for obtaining high surface integrity features with variable inclination angle force control

Abstract

The blisk was a new type of component for high-performance aero-engines, which could significantly improve the energy efficiency ratio of the engine, however there were also shortcomings such as narrow structure and difficult material removal. Robotic belt grinding was widely used in the processing of key complex surfaces such as blades, fairings and propellers, which is due to its large processing space and high flexibility. Nevertheless, how to improve the surface integrity of the blisk under the premise of ensuring the profile accuracy was a challenging problem. In view of the above problems, this study started with the grinding force, and innovatively proposed a robotic belt grinding method for high surface integrity of blisk based on variable inclination angle force control. Firstly, a belt grinding robot based on macro-micro-end hand structure and electromagnetic force-controlled end was designed based on indirect arm-winding control. Secondly, an adaptive variable impedance compliance based blisk grinding model was established through the relation expression of grinding end and the mathematical formula of inclination contact micro-surface control, which effectively coordinates the coupling relationship between force control and trajectory under inclined attitude. Lastly, the experimental study proved that the normal grinding force of this method was stable and the error was 1.14 %, the surface hardness and residual compressive stress were improved by about 8.57 % and 52.82 % respectively, the surface morphology was uniform and the surface defects are well suppressed. The surface integrity of the blisk was significantly improved.