Aiming at digital measurement of gap and step difference, a measurement technology based on multisource measurement data fusion was proposed. The measurement method using vision measurement sensor and omnidirectional robot assisting actuator was presented and the measurement system composition was analyzed. Based on the research, measurement process based on measurement data fusion was proposed. In order to measure automatically, multi-system integration framework and control method was studied. Finally, a QT-based gap and step difference measurement software and omnidirectional robot measurement platform was designed and developed to carry out verification. The research provides technical support and methodological guidance for automatic and high-accuracy measurement of gap and step difference.
In order to solve the inadaptability of Augmented Reality (AR) application system in universality and integration, and meet the practical requirements of aircraft assembly, this paper presents a new Aircraft Assembly AR Intelligent Pilot System (A3-IPSAR). Firstly, two key technologies, universal AR assembly instructions based on dynamic operation description and integrated operation pilot based on continuous operation state, are studied. Secondly, an AR intelligent pilot system is constructed for aircraft assembly operation. Finally, the system is applied to pipeline assembly of aircraft hydraulic system in laboratory environment. It is preliminarily realized that the real-time pilot and intelligent inspection applied in the assembly process of hydraulic pipelines are feasible.
In traditional assembly management process, the real-time information cannot be obtained in time. As a result, the production plan is not coordinated with the actual assembly process, which causes the loss of efficiency. This paper mainly studies an aircraft moving assembly line management technology based on Internet of Things (IoT). With the proposed method, all kinds of real-time information and data are collected, analyzed and sorted via Internet of Things. Combining information system such as takt design and management system, production plan and execution system, and etc., the monitoring and controlling of the aircraft assembly process, the production process tracking and quality control can be achieved. IoT technology can provide a reliable and efficient advanced management tool for aircraft moving assembly line.
A locator bracket hybrid attitude positioning platform is adopted, and a digital positioning method for aircraft thin-walled flexible large parts is proposed. Firstly, the singular value decomposition (SVD) computer wing pose is used to obtain the motion state of each axis of the positioner through kinematic inverse solution. Secondly, according to the characteristics of the large deformation of the aircraft, a method for establishing the coordinate system of the aircraft components to eliminate the pose error is proposed to achieve fast and high-precision attitude adjustment. Finally, the method is applied to the attitude of the aircraft wing, and the measured attitude accuracy meets the assembly requirements.
In the alignment of large parts of aircraft supported by numerical control localizer, the accurate orientation of large parts is the basis to ensure the accurate alignment of large parts. In order to reduce the error of the pose fitting of large parts, four key measurement points on large parts were measured by laser tracker. A method of fitting large parts pose vectors was proposed based on the position accuracy requirements of different measurement points. This method has the advantages of fast convergence speed and small fitting error, and is a good method to estimate the pose vector of large components accurately.
In order to solve various bottleneck problems in aircraft development under the main manufacturersupplier patterns, learn from the ideas of modular assembly in the automotive and marine industries, the idea of modular assembly for aircraft was proposed, and the process design of modular assembly for aircraft was analyzed. Based on the design data structure modularization, system modularization, functional modularization and interface standardization, expand aircraft assembly parallel working plane by method of the aircraft top-level modular assembly process design, optimized division of work, detailed delivery status and integrated assembly, etc. Reduce the working difficulty of the final assembly stage by the work in advance, and give full play to the advantages of the main manufacturer-supplier patterns to achieve the goal of maximizing the efficiency of aircraft assembly work. Therefore, the main manufacturer-supplier patterns can shorten the total period of model development, ensure the model development node.
In order to reduce the defects in the joint area of Ti–6Al–4V titanium alloy laser-formed joints and improve the joint quality, orthogonal test method is used to optimize the process parameters. The comprehensive assessment indicators include tensile strength, yield strength, elongation and internal quality. And the influence degree of each process parameter is analyzed by mathematical statistics, which provides near-optimal process parameters for the study of mechanical properties of subsequent forming joints. The result shows that: when the line energy density is 0.5W · min/ mm2, groove angle is 70°, scan path is +60°– –30°, we got the near-optimal evaluation result. And the linear energy density of each parameter has a significant effect on the tensile property of the joint specimens. The joints can meet the national standard when the optimized process parameters are used. The result shows that the method can provide a reference for reasonable selection of the joint forming process parameters and ensure the quality.
Additive manufacturing bring challenges for the nondestructive testing techniques, anisotropic and large non detection zone were the major obstacles. Therefore, researchers in the world have studied the NDT for additive manufacturing. The application of metal additive manufacturing technology in aeronautics and astronautics was introduced. The application features of NDT methods were analyzed, the research progress on nondestructive testing of metal additive manufacturing was introduced, including UT, RT, CT and FPT. The related nondestructive testing standards are analyzed. The future development direction of NDT for additive manufacturing metal components is pointed out, that is, high precision NDT, in-situ monitoring and the construction of standardization system.
The superplastic forming process of the core was simulated by using the finite element software, to obtain the thickness distribution and the pressure-time curves. The four-sheet structure rudder of Ti60/TA15 alloy was obtained at 920℃. The thickness of the rudder was investigated. The results show that the minimum thickness is 1.24mm and the maximum thickness is 1.80mm. The moulding surface for the four-sheet structure rudder of Ti60/TA15 alloy was measured by using the 3D scanning. The results show that the tolerance of more than 90% is less than ±0.2mm, and the global is less than ±0.5mm. The interface of diffusion bonding was investigated by the metallograph observation. The results show that at 920℃, interfaces of diffusion bonding between the same materials of TA15 and between the different materials of TA15 disappear basically, and no holes can be seen at the three diffused interfaces.
Aero-engine parts such as blisks and impellers have complex shapes and high precision requirements, which pose great challenges to traditional processing methods. Additive-subtractive hybrid machining method can be used to machine before obstacles formed, which is an effective way to solve complex part processing problems. In view of the above problems, the impeller is decomposed into two parts, the blade and the disc based on geometric features. The fiveaxis annular slicing method is used to plan the additive-subtractive hybrid machining process of the impeller. Based on an self-built five-axis hybrid processing platform, an impeller was processed and tested to verify the feasibility of the hybrid processing planning method proposed in this paper.
During the electron beam rapid manufacturing procedure of large metal work piece, the electron beam is used for scanning and heating in order to implement real-time annealing treatment which can eliminate the residual stress in the electron beam freedom fabrication process and reduce the deformation caused by the stress accumulation. In this paper, an electron beam high-frequency deflection scan control experiment platform, which consists of industrial computer, waveform generation card, drive circuit, and deflection scanning coil, is built to generate X, Y output waveform, do rectangular scan and circular offset scan. LabVIEW is used to develop the software interface. A real time annealing finite element model is built to analyze the influence of scanning on temperature distribution difference in a range of 100mm×100mm. The conclusion is the temperature difference in the area is reduced from 94℃ to 11℃ which improves the uniformity of the temperature distribution when the beam current is 30mA, beam spot radius is 4mm, beam spot overlap is 1mm, and using the electron beam to scan for 0.6323s with a speed of 25m/s.
It is a big challenge for the traditional calibration to make friction and backlash, so a wide scale and high accuracy calibration technology of linear displacement sensor is proposed. Taking laser interferometer as the reference, linear motor and bearing sliders are the driving unit, the grating achieves closed-loop control, and the positioning accuracy is on the micron level. Meanwhile, by a six-degree-of-freedom adjustable fixture in the calibration process, the reference direction is aligned with the measurement direction to eliminate the Abbe error. Meanwhile, aiming at the special float type sensor, a special fixture is designed to eliminate the deformation with support points, which solves the deformation problem of the measuring rod in the calibration process. The evaluation and verification of the uncertainty show that the calibration method is feasible and effective.
In order to study the forming method and forming limit of H62 copper spiral corrugated tubes, ABAQUS simulation and experimental research on tube incremental forming are carried out. For the first time, the spiral corrugated bellows are processed by the incremental tube forming method. Through the combination of simulation and test, the process parameters of the incremental forming of the tube are optimized, and the forming precision and forming limit of the H62 copper spiral corrugated tube were improved by theoretical analysis. The test results show that when the single feed of the tool head is 0.50mm, the spindle speed is 10r/min, and the axial feed speed of the tool head is 6.7mm/s, the thread depth limit is increased. When the thread depth is 2.5mm, the forming quality of the bellows is the best, and when the thread depth is more than 6mm, the forming quality is remarkably lowered.
