Research On Some Key Techniques On Aircraft Large Part Automatic Joining

Aircraft assembly plays a great role in the aircraft manufacture, and it is the key and coretechnology of the aircraft manufacture. Aircraft final assembly is the final stage after Aircraftcomponent assembly. Large part joining is the main portion of the aircraft final assembly, therefore thequality of large part joining determines the aircraft quality, manufacture cost and manufacture cycle to agreat extent.The conventional assembly method is still adopted for the large part joining in China. Theconventional assembly method is inefficient and has unstable precision and low quality, which can notsatisfy the higher efficient and less cost of the modern aircraft. Digital measurement system,information management and NC automatic positioning should be adopted for the modern aircraft largepart joining. By using these new technologies, the large part joining will go towards automation anddigitalization. Unfortunately, these new technologies and equipments are controlled by the foreigncountries. Taking wing and fuselage joining as the research object, survey control network for the largepart joining, flexible automatic position and pose adjustment mechanism, trajectory planningalgorithms for joining, position and pose tracking measurement method and automatic joining systemare studied for improving the large part joining. The main contributions in this thesis are as follows:(1) Survey control network is presented for the aircraft large part joining. Adjustment model of thesurvey control network is established. Using the adjustment model, the relationship between the publicreference points and survey control network is studied. The layout rules of the survey control networkare presented.(2) Position and pose automation adjustment positioner is designed for wing and fuselage.According to the structural and dynamic characteristics, wing and fuselage adjustment mechanisms areseparately set up. The relationships between the positioner errors and adjustment errors are builded.(3) In order to avoid Jacobi matrix singularity during iterative solution, The damped least squareiterative solution method is proposed for large part position and pose iterative solution. Damped leastsquare method and cholesky decomposition are combined for the solution method.(4) The kinematic equations of position and pose adjustment mechanisms are separatelyestablished. Using the kinematic equations, Jacobi matrices of position and pose adjustmentmechanisms are separately drived which are expressed by roll, pitch and yaw. The dynamic equationsof position and pose adjustment mechanisms are separately established. According to the dynamiccharacteristics, trajectory planning algorithms are separately proposed for wing and fuselage automatic joining.(5) Position and pose tracking measurement method is presented for the large parts. State equationof each stage and observation equation are established, moreover unscented kalman filter andextrapolation iterative algorithms are presented for position and pose.(6) Wing and fuselage automatic joining system is presented. Functions are planned for each part ofthe automatic joining system. Wing and fuselage joining data set, wing and fuselage joining aidedmeasuring system and wing and fuselage joining data processing system’s architectures are established.Wing and fuselage joining aided measuring software, wing and fuselage joining data processingsoftware and wing and fuselage joining motion controller software are developed. The control platformis putted up for wing and fuselage joining.(7) Wing and fuselage joining automatic joining platform is putted up for ARJ21-700and automaticjoining process is made. By using the automatic joining platform, ARJ21-700wing simulating part andfuselage simulating part automatic joining is implemented.