Research On Assembly Coordination And Accuracy Base On Hole Feature

In order to improve the quality and efficiency of the aircraft digital assembly,we need to adjust the posture of component to the ideal position which meet the assembly and coordination requirements.This paper analyses some kinds of assembly accuracy in the process of manufacturing such as straightness angle and deep-hole butt joint by fitting this assembly accuracy into mathematic expressions.Then an alignment-optimized algorithm model based on the constraints of assembly accuracy is set up by the further studying of constraint evaluation in digital assembly technology.We can evaluate the current posture as well as get the optimized posture which guarantees the integrated assembly error by solving the model.In chapter one I summarize the domestic and overseas research status of aircraft digital assembly technology and introduce the key basic technology and application of large components digital alignment.The background and the meaning of this studying are presented.At last,the overall framework of the thesis is given.In chapter two the concept of manufacturing accuracy and coordinated accuracy in digital aircraft alignment are introduced,while the transformation of aircraft component in the space is described.Then we propose the method to evaluate the posture on the behalf of the process feature deviation given by the relationship among the coordinate system.In chapter three,according to the technical requirements of aircraft assembly and the quality evaluation standard,some common assembly accuracy are introduced.By discussing some assembly accuracy like the straightness of the wing rib and the symmetry of the wing’s sweepback,we show the application of this coordinate way.In chapter four,the coaxiality of the most common existing coordination forms-lug type joint and the fit between the hole and shaft is discussed in the middle of alignment.With the help the interchangeability I can solve the coordination between the joint of the two coordinate way above and relocate the tolerance.In chapter five,an optimized posture evaluation algorithm based on the manufacturing accuracy and the accuracy of deep-hole butt joint which ensures the assembly accuracy is proposed which transfer the deep hole coordination into the distance between a point and the axis.We solve the optimized posture model by using PSO,and then we get the best posture which can satisfied the reasonable allocation of the deviation.In the last,we applied the algorithm through the simulated data which from the key process of large aircraft component which verifies its validity.In chapter six summary for whole work in the thesis is given and future work is discussed.