Study Of Aircraft Skins Trimming Technology Based On Industrial Robot

Aircraft skins are key parts of the aircraft aerodynamic shape, theirs accuracy have a significant impact on the stability of the aircraft in flight. Aircraft skins trimming is a process of cutting the excess skins edge after the panel-forming. In modern aircraft manufacturing, the mainly methods of skins trimming are manual trimming and reconfigurable flexible fixture, but manual trimming is a low efficiency, high labor intensity method and the accuracy is difficult to guarantee; Due to the expensive price and relatively late development of reconfigurable flexible fixture, it is not used widely in our country. Therefore, it is very necessary to seek an efficient、 accurate and economical method of skins trimming. Against this background, investigations are done in this thesis to solve some questions existing in robot milling skins system, which demonstrates the feasibility of aircraft skins trimming based on robot.Firstly, the development and application of aircraft skins trimming technology and industrial robot in aircraft assembly are summarized. Based on this background introduction, the significance of the research, as well as the main points in this thesis are given in chapter 1.All the tests done in this paper are based on the robot milling skins system platform, which is described in detail in following aspects, involving KUKA robot, robot moving platform, orbital milling end-effector, laser tracker measurement system and robot automatic control system. According to processing needs of skins trimming, the process of robot milling skins is developed. In order to achieve accurate and smooth robot motion along a complex trajectory, each coordinate system and its construction process is described; the machining path planning and off-line programming method of robot is given in this paper.The stiffness of the robot and the skins is relatively weak; so the milling force will lead to processing defects caused by strong vibration, such as poor quality of skins trimming. To solve this problem, an orbital milling method is proposed. The orbital milling parameters were studied through orthogonal test and the empirical models of circumferential milling force and surface roughness were established. Then, the orbital milling parameters were analyzed deeply; it was shown that the feed per revolution has a most significant effect on the circumferential milling force and surface roughness.Considering the requirements of both processing quality and efficiency, the optimal set of process parameters was obtained. It is verified that the experiment system of robot milling skin works steadily and reliably, with the processing efficiency is 48 mm/min, the contour accuracy is±0.15 mm, and the roughness is controlled under 4 μm, without burr. It provides a new idea and method for aircraft skins trimming.