Research On Digital Coordination Technology In Aircraft Assembly

Coordination is one of the key technologies in the aircraft development,and digital coordination technology is gaining extensive attention and achieving certain technical breakthrough in recent years.The thorough research of digital coordination has been conducted abroad,and a perfect technological system of digital quantity coordination has been built,which is widely applied in aviation companies such as Boeing and Airbus.However,domestic aircraft manufacturing is in transition period from analog coordination mode to digital coordination mode.Although two kind of modes are combined in the application,some problems such as high cost,long period and huge local assembly error are still existing,and the fully digital assembly coordination technology is still in the stage of research and exploration.Therefore,it is significant to study the key technologies of fully digital assembly coordination,form the theory method of digital assembly coordination,and to perfect digital propagation system of the size and shape,there are important theoretical significance and application value for the development of domestic aviation industry.The paper's major work and innovative points are as follows:1.A digital assembly coordination work method is proposed based on coordination model.Aiming at the complex propagation procedure of size and shape by analog coordination mode or mixed coordination mode,and coordination accuracy is difficult to guarantee,the principles of fully digital assembly coordination have been studied and a fully digital,closed loop coordination control method has been put forward,which is on the basis of digital coordination model,on the guide of product assembly propagation of error,according to measured data,by means of dynamic feedback adjustment,and taking the dimension consistency of coordination as the core.A technical system of fully digital coordination has been established to ensure consistency of assembly dimension,which consists of identification and control of coordinate elements,relationship analysis of assembly coordination and establishment of assembly coordination dimension chain.2.A fully digital coordination model has been built which can be regarded as the unique basis of coordination,meanwhile,an application mode of coordination model is formed in aircraft manufacturing.The coordination model is defined as a process model,including coordination element,coordination relationship and coordination method.Its key elements contain numerous coordinate system,design/process baseline system and constrained relationship etc.Different stage application patterns of coordination model have been set up systematically,such as part manufacturing and components/parts/big parts assembly.The stages are divided according to hierarchy relationships of product and business process of manufacturing,iteration relation between coordination model and engineering data set,and functional attributes and process attributes of coordination elements.Namely,by taking the coordination relationship and coordination elements as reference and under the guidance of coordination method,digital coordination information achieved precise delivery.Comparing the testing result with accuracy requirement of coordination model,the process of machining,forming,positioning and assembly need to adjust to fulfil coordination requirements,as well as the coordination data of coordination model.3.A qualitative and quantitative combined recognition method of product coordination elements and a hybrid mapping method between the coordination elements of product and process were proposed.The coordination elements were decomposed hierarchically based on product manufacturing tree.The mass loss of goal coordination elements caused by each alternative coordination elements between different assembly levels was calculated based on the Taguchi Quality Loss Function.Further,the degree to be of influence and the degree to be influenced of each coordination element was calculated by the theory of fuzzy DMATEL(Decision Making Trial and Evaluation Laboratory)method.Then the qualitative and quantitative combined recognition method of product coordination elements was completed.What's more,mapping design information to process information was achieved by constructing a mapping function based on the product design domain information.And the mapping relationship between the coordination elements of product and process was established by adapting the polychromatic sets theory.While,combined with the selection of measuring equipment,establishment of measurement benchmarks,optimization of measuring sampling and layout,measurement path and measurement sequence,mapping the design domains,domain processing and tooling domain information to the measurement domain was implemented.4.The assembly coordination relational model was established based on the coordination element,and the error model of a single coordinated control link was constructed.First,considering the complexity of the aircraft assembly level and the coordination relationship between different assembly stations,a coordination relationship model integrated product structure,assembly coordination process,technology and equipment information,coordination and other constraint information was set up.Then the state of the aircraft coordination sites and the complete coordination relationship were expressed.At last,the error model of a single coordinated control link was constructed according to the coordination elements recognized,which reflects the coordination constraint state between the coordination parts.5.The coordination error propagation and dimension chain construction based on the state space equation was proposed.At the same time,the coordination dimensional consistency was controlled according to the analysis of statistical process and assembly station flow volatility.The basic error sources and its interaction during assembly coordination process was modeled and analyzed.Taking into account the multi-level and multi-position conversion characteristics in the aircraft assembly,the coordinate reference transformation process was defined,and its corresponding error term was analyzed.Combined with the aircraft assembly steps,the error propagation model of each coordination control link was conducted.And the coordination dimension chain of multi-station assembly was constructed.Then the segment having a large influence on the accuracy of the coordination had been feedback optimized.Further,the discriminant criterion lead to the incoordination in aircraft assembling was summarized by constructing statistical sample based on range chart X-R_s.According to the dynamic changes of assembly data at different time stages,the concept of flow volatility stations was proposed.In order to improve the assembly coordination,the fluctuation diagram of station flow was drawn and the assembly process was adjusted.6.A prototype coordination system for aircraft digital assembly was developed and verified.By choosing the assembly coordination of the leading-edge flap in a certain aircraft as an example,its corresponding coordination model was established.Then the application of full digital coordination method during the stages of design,fabrication and assembly based on the coordination model was achieved.At the same time,a comparative analysis of the coordination route between the intersection of leading-edge flap and wing body based on the coordination model and standard gauge was carried out.And the validity and accuracy of coordination work method based on the coordination model was verified.That is to say,(1)The propagation of the aircraft products size and shape can be completed by the work method based on the coordination model without the use of physical standard tooling.(2)The propagation result of the coordination accuracy meets the design requirements.