Modern aircraft has large fuselage size, weak structural rigidity and strict requirements for aerodynamic shape accuracy. It&nbsp;leads to complex process, difficult accuracy guarantee and low efficiency in large fuselage component butt. Especially in the process of plug-in butt joint&nbsp;of large fuselage components, there is an inherent problem that the butt end face is invisible and unmeasurable, which is more likely to lead to interference or uneven gap, and eventually lead to the decline of repeated trial assembly and connection quality consistency, and affect the assembly efficiency and fatigue characteristics of local structure. Aiming at the problem of fuselage large component&nbsp;plug-in assembly,&nbsp;the digital measuring&nbsp;technology, numerical control attitude adjustment and positioning technology and visual virtual simulation technology are comprehensively applied to guide the digital attitude adjustment and butt joint&nbsp;through measurement modeling and trial assembly simulation, which makes the "invisible and unmeasurable" process of plug-in butt joint&nbsp;explicit. It has&nbsp;important theoretical and engineering application value.Taking the butt joint&nbsp;of the front and the middle fuselage of the civil aircraft MA700, this paper realizes the pre-assembly simulation of the fuselage component&nbsp;based on the measured process model. It studies the space measurement of the large parts, multi-degree of freedom positioning and attitude adjustment, virtual simulation verification and process data closed-loop control technology in the large fuselage&nbsp;component butt. The main contents of this paper are as follows：(1)The research on large space measurement and 3D model reconstruction technology of fuselage is carried out. The working principle of space measurement instruments and equipment is described, and the benchmark measurement field of experimental verification space is constructed. At the same time, the measured dynamic process model of fuselage component&nbsp;is constructed. A&nbsp;digital process flow suitable for accurate position,&nbsp;attitude tracking and measurement of large fuselage component is designed.(2)Based on the position data of measurement points in space, the butt joint&nbsp;process planning of fuselage components is carried out and the data communication with the measurement system is realized. The posture adjustment platform dynamically obtains the space posture measurement data, and realizes real-time posture dynamic adjustment by continuously adjusting the posture of the fuselage within the design error range. In-depth study of the transformation relationship of each coordinate system in the assembly site&nbsp;is realized; the unification of the global coordinate system, aircraft coordinate system and measurement coordinate system&nbsp;is completed. Study&nbsp;of&nbsp;the calculation method of the measurement posture point&nbsp;is realized. And it sends&nbsp;the adjustment parameters of multi-degree of freedom in space to&nbsp;the posture adjustment motion mechanism in real time.(3)The hand-held 3D sensor is used to obtain the point cloud data of the fuselage butt end face contour. With the virtual simulation technology, the trial assembly simulation analysis of the fuselage plug-in butt joint&nbsp;process is carried out based on the measured data. With zero interference and clearance uniformity as the goal, the fuselage pose is slightly adjusted. Guided by the final optimized fuselage pose, the one-time accurate positioning of the large part of the plug-in process is realized. At the same time, the change of the clearance uniformity of the plug-in end face is obtained through the linear laser scanning of the characteristic position of the butt end face&nbsp;to&nbsp;ensure the accuracy of the actual assembly of the fuselage. It avoids&nbsp;repeated trial assembly and improves&nbsp;the assembly efficiency.(4)Taking the equal scale reduced test pieces of MA700 front fuselage and middle fuselage as the verification object, a complete butt joint&nbsp;assembly test environment of fuselage barrel parts is built. The large space measurement module, space pose calculation module and virtual simulation module are integrated to verify the effectiveness of the simulation and accuracy guarantee technology of fuselage component&nbsp;trial assembly based on dynamic process model. At the same time, three-dimensional visualization is performed to complete the closed-loop control of the overall butt joint&nbsp;data flow.

Simulation and Accuracy Guarantee Technology of Fuselage Component Trial Assembly Based on Dynamic  Process Model

Paper Proceedings: https://asmedigitalcollection.asme.org/IMECE/IMECE2021/volume/85543

ASME 2021 International Mechanical Engineering Congress and Exposition (IMECE2021)

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