Abstract: In order to realize the automatic grinding processing of aviation bends, a planetary-like mechanism is designed for robots to automatically grind the surface of aviation bends. The 3D modeling design of the planetary mechanism is completed by analyzing the grinding process requirements. Based on the theory of material mechanics and strength, the strength of the first-stage driving gear and the first-stage large gear was calibrated, and the mesh division was carried out by Hypermesh software, and the implicit dynamic simulation was analyzed by Abaqus software. The robot automatic grinding test on the outer surface of the bend was carried out to verify the feasibility and controllability of the planetary-like mechanism for grinding the bend. The processed bends have high precision, good surface quality consistency, stable surface roughness in the range of 0.55−0.70 μm, and stable wall thickness removal allowance of the bends in the range of 25±5 μm. The results show that the planet-like mechanism can well realize the automatic grinding processing of the outer surface of the bend, the processing quality meets the process requirements, and the processing feasibility, controllability and stability of the mechanism are good.