In recent years, China is making great efforts to develop aerospace industry. The building of flexible manufacturing units or production lines and the realization of rapid, flexible and automated production based on industrial robots play important roles in transforming and upgrading the production mode of aerospace manufacturing enterprises and upgrading equipment manufacturing capabilities and product performance. However, due to limitation of the structure of the base and environment, the absolute positioning accuracy of the industrial robot is low and the long-term stability is poor.Therefore, the industrial robot can not directly adapt to the applications and demands of various industries in the modern new manufacturing environment. This paper reviews and summarizes the current research methods and technologies in improving robot positioning accuracy at home and abroad, and puts forward the research ideas of improving the positioning accuracy of industrial robots. It has a certain guiding significance for the application and development of industrial robots in aerospace industry.

In aircraft manufacturing, there are various types of physical toolings such as template, master tooling,mould and so on. It is quite a challenge to convert these physical toolings to digital ones due to their variable forms and complex shapes which comprise freeform surfaces, complicated carved curves and details. In this paper, the 3D metrology and model reconstruction method for digitizing the physical toolings are discussed. First, the crucial geometry elements in design of aircraft manufacture tooling are summed up and analyzed. Then, an integrated 3D metrology, which composites a photogrammetry, a structure light scanner, and an optical tracking tactile probe, is utilized to capture the physical toolings. The integrated metrology combines the advantages of all of the three techniques and is able to provide measuring data with completeness and high precision. Thereafter the strategy for improving the process efficiency is presented by considering the size, form and complexity of the physical toolings. For the tooling with large size and high complexity, the converting strategy is set to not use the whole measuring data, but the surface point clouds, a few basis carved curve points which indicate the structure of the aircraft, and the existing 2D drawings. It is highly efficiency and the precision meets the needs.

Aiming at dealing with the problem of digital detection of flush and gap between aircraft skins, the measurement technology of detection method is studied based on the grating projection technology. Firstly, the dense point cloud data of surface to be measured is obtained using the technology of grating projection; Then, the seam area is positioned from the image, and the point cloud data of the seam area is obtained according to the correspondence between the point cloud and the image; After that, the point cloud data is analyzed and the joint on both sides of a straight line segment is determined. And based on them, the flush and gap are calculated. Compared to the structure line technology, the proposed method can obtain more data. Besides, we can analyze all seams during one measurement and thus, the detection efficiency is very high. The experimental results show that the mean error of the proposed method is less than 0.03mm and the maximum error is less than 0.05mm, which can meet the requirements of aircraft skin seam testing.

For the needs of quick and accurate inspection of assembly connection holes on skin, skeleton and otheraircraft parts, an on-machine vision inspection system was designed and developed. A specifically developed vision sensor is installed on the moving end of the five-axis CNC machine tool. According to the inspection path programed offline, themachine tool carried the vision sensor to each pre-determined position to grab image of each connection hole. The system software extracted and located the actual information of the connection holes from the image in a parallel processing way. An error evaluation procedure was developed in the software to finally complete the non-contact rapid connection hole inspection. The work flow, software and hardware architecture of the system were introduced. The key techniques such as the calibration of system parameters, the generation of NC inspection codes and the error evaluation method were discussed in detail. The inspection results of actual aircraft parts demonstrate that the efficiency of the developed on-machine vision inspection system is as high as 5s/hole, and the precision is about 0.01mm. It well satisfies the inspection requirements of large quantity of small size connection holes distributed on complex surfaces.

The technology of three-dimensional inspection planning for parts is studied. An inspection planning and quality assessment framework based on multi-geometric characteristics is proposed. Then it is introduced through measurement requirements expression based on MBD, inspection planning, measurement execution and data preprocessing, and quality assessment. Finally, the prototype system was developed in the CATIA secondary development platform and the preliminary verification was carried out. The research provides technical support and methodological guidance for engineering and comprehensive evaluation of model-based measurement planning technology.

To improve the accuracy of curved pipes measurement, a point cloud fusing-based measurement method was proposed. The principle of machine vision was utilized to extract coordinate of the marked points from images taken from cameras, and the marked points were used as fixed points in the process of 3D scanning to obtain the uniform point cloud. Point cloud fusion technology was used to obtain the 3D digital model of curved pipes. Experimental results showed that the maximum absolute deviation between measured values and standard value was 0.16mm. This method can effectively improve the accuracy of curved pipes measurement.

Aiming at the difference of measuring technology needed for the assembly of large and complex aircraft structural parts, a collaborative measurement method based on Metronor dual-camera tracking system, hand-held light pen and Aicon scanner was developed. The hand-held light pen and three-dimensional scanner measurement were proposed, the technical scheme omits the work of attaching and removing the reflective mark points, and the testing process in the space of 4m×3m×2m with the measurement error of no more than 0.075mm, which can realize the measurement of internal hidden features, hole position information, axis, mating surface, aerodynamic profile and the gap step, meets the requirements of three-dimensional digital measurement for large complex structures assembly on aircraft.

It is costly, inefficiency and low accurate using traditional rigid assembly tooling for aircraft parts joining. Airliner parts have large structure with high assembling accuracy. Using digital automatic locating technology can complete the accurate locating of aircraft parts, improving the quality and efficiency of aircraft parts assembly with lower manufacture cost. This paper introduces the implement process of digital automatic locating technology and elaborates application process of digital automatic locating technology for forward fuselage of C919 in detail, which has an important reference value for the digital automatic docking assembly of large aircraft parts.

Compared to traditional metal materials, SiCp/Al composites has excellent physical and thermal properties. However, hole edge quality in the he holed drilling process becomes one of the main problems influencing the usability of the composites. In this paper, experimental study on drilling of SiCp/Al composites with diamond coated bits is carried out, the measured mechanical signals, the formation mechanisms and characteristics of hole edge defects are analyzed. It is shown that in the drilling process the process parameters have influence on the thrust force, and their effect are ordered as each drill depth, feed speed and spindle speed; the hole quality at the exit is better than that at the entrance; the defect formation mechanisms mainly include the fracture of Al matrix and the detachment of SiC particle. And the diamond coated bits are suitable for the drilling of SiCp/Al composites. It has reference value for the actual processing and application of SiCp/Al composites.

With high frequency, high sensitivity and high signal-to-noise ratio characteristics, acoustic emission is widely used in the detection field. When drilling composite laminated material, the acoustic emission signal will be generated with the wear of cutting tools. To obtain the relationship between time and frequency domain characteristics and tool wear condition, using high-speed steel and carbide drill conducted a series of experiments, collecting acoustic emission during the drilling process. The results show that the acoustic emission signal can be used to monitor the wear status of laminated materials. The RMS value and wavelet packet energy of acoustic emission signals are closely related to tool wear.

Metal fatigue and corrosion failure is one of the key factors that limit the daily life of aircraft, and affect aviation safety. Rolling reinforcement is a widely used mechanical surface strengthening technology which can improve the fatigue strength and corrosion resistance of aeronautical metal parts effectively. The strengthening mechanism of rolling technology is presented, the research status of rolling technology both at home and abroad is introduced, and at last the application status of rolling technology in aviation field is summarized. It can be seen that, with the continuous breakthrough of rolling technology, the strengthening effect will be getting better and better, and the application field will be more and more wide. Apart from the benefit of improving aviation safety and security, the low price advantage of rolling technology application can bring great economic profit.

This study uses Fluent software to simulate the temperature distribution of the forming mold, analyzes the reason of the temperature distribution and uses variance as a standard to evaluate temperature uniformity. According to the characteristic that the thermal resistance is proportional to the material thickness, we improve the uniformity of temperature by increasing the thickness of high temperature area and reducing the thickness of low temperature area. The simulation result shows that ladder type plane mold and trapezoid plane mold can make the temperature distribution of the contact plane more uniform, which has great significance for improving the quality of the composite material components.

The effect of shot penning on the surface integrity and fatigue life of TC17 alloy was investigated. The effect of shot type and shot peening intensity on surface roughness, residual stress, microhardness, and microstructure was analyzed by using surface roughness tester, a scanning electron microscopy, X-ray diffraction residual stress analyzer, microhardness instrument, etc. The fatigue life before and after shot peening was tested by rotating bending fatigue testing machine. The relationship between surface integrity and fatigue life was discussed. Results show that surface roughness (Ra) of 0.5~1.0μm was obtained after shot peening, the thickness of compressive residual stress layer was approximately 100μm,and the maximum compressive residual stress was located at about 30μm depth beneath the surface, work hardening and grain deformation were observed. Compared with the fatigue life of untreated specimens, the longest fatigue life is obtained when utilizing glass shot, then utilizing ceramic shot, last utilizing cast steel shot. The mechanism of improving fatigue life after shot peening is due to the induced deep compressive residual stress layer, high surface hardening degree and surface grain refinement.

Carbon fiber reinforced SiC matrix composites (C/SiC) are considered one of the most potential alternative materials for high temperature alloy due to a series of advantages, such as the high temperature resistance, oxidation resistance, high specific strength and high specific modulus, etc. However, the ablation resistance property of C/SiC composites should be modified because the oxidation of carbon fiber and the volatilization of SiC matrix oxidation products under the ablation environments. At present, the methods for improving ablation resistance property of the C/SiC composites mainly focus on optimizing the carbon fiber preform structure and enhancing the density for composites, modifying the SiC matrix with ultra high temperature ceramics and fabricating anti-ablative coatings at the surface of C/SiC composites. Several domestic research work of modified ablation resistance C/SiC composites were reviewed and summarized, and the key problems faced for the preparation process of modified C/SiC composites were also proposed at the same time, which could provide a train of thought for the modified C/SiC composites research.