3D Microdisplacement Monitoring of Large Aircraft Assembly with Automated In Situ Calibration

Three-dimensional(3D)microdisplacement monitoring plays a crucial role in the assembly of large aircraft.This paper presents a broadly applicable high-precision online 3D microdisplacement monitoring method and system based on proximity sensors as well as a corresponding in situ calibration method,which can be applied under various extreme working conditions encountered in the aircraft assembly process,such as compact and obstructed spaces.A 3D monitoring model is first established to achieve 3D microdisplacement monitoring based only on the one-dimensional distances measured by proximity sensors,which concerns the extrinsic sensor parameters,such as the probe base point(PBP)and the unit displacement vector(UDV).Then,a calibration method is employed to obtain these extrinsic parameters with high precision by combining spatial transformation principles and weighted optimization.Finally,calibration and monitoring experiments performed for a tailplane assembly process are reported.The calibration precision for the PBP is better than±10 lm in the X and Y directions and±2 lm in the Z direction,and the calibration precision for the UDV is better than 0.07°.Moreover,the accuracy of the 3D microdisplacement monitoring system can reach±15 lm.In general,this paper provides new insights into the modeling and calibration of 3D microdisplacement monitoring based on proximity sensors and a precise,efficient,and low-cost technical means for performing related measurements in compact spaces during the aircraft assembly process.

A CAD EXPERT SYSTEM OF AIRCRAFT MANUFACTURING COORDINATION

讨论了工程CAD专家系统特点，提出其一般结构。为了解决如飞机制造协调等复杂工程问题，实现一种层次分布式CAD专家系统（HDES）结构。HDES由元级、任务级两个水平的分布式专家系统组成：任务级专家系统（T－ES）主要用于应用设计，它们在其自己的设计领域中执行；元级专家系统（M－ES）则处理合作。介绍了层次－框架－规则的专家系统组织表示方法。

Attitude Analysis in Process Conflict for C919 Aircraft Manufacturing

Based on the option prioritization in graph model for conflict resolution of two decision makers(DMs),new logical and matrix representations of four stability concepts for DMs′attitude are proposed.The logical representation of attitude is defined,and converted to the matrix form in order to develop a decision support system(DSS)efficiently.Compared with existing definitions of DMs′attitude based on states,the proposed definitions of attitude based on options are convenient and more effective to generate preferences since that of states can be significantly larger than that of options in a large conflict.In addition,it is easier to obtain the information of the prioritization of option statements than to obtain preference of states for users.The proposed representations are applied to the process conflict during aircraft manufacturing to demonstrate the efficiency of the new approach.

Spatial Organization Mechanism of Aircraft Manufacturing

Unquestionably,aircraft industry plays an important part in both economy and security of a nation.However,few of articles have dealt with the spatial development of this industry sector.The purpose of this article is to analyze the dynamics of agglomeration and diffusion of aircraft industry.In a historical view,with some spatial analysis methods,this research discusses the characteristics and patterns of aircraft industry's spatial organization and evolution,globally,nationally and regionally respectively.We find out there is a ‘Matthew effect' in aircraft industry of the world,and the spatial evolution of the industry is consistent with the nation's industrialization process.Then,it concludes that the main agglomeration forces consist of capital,talents,technology and cluster's advantages,and the main diffusion forces include comparative advantages,cost and risk sharing,emerging markets,development policy for backward regions and military requirements.All the factors can be divided into market forces making the spatial development of aircraft industry normal and non-market forces making that irregular.In particular,lessons from the USA and France are expected to be conducive to the rise of China's aircraft industry in the future.

Study on a Maturity Model of Project Management Capability for a Large Aircraft Main Manufacturer

This paper is to study a maturity model of project management capability for a large aircraft main manufacturer using a capability maturity model and an organizational project management maturity model.First,we build the project management capability maturity level,its features,key process areas and best practices to provide a clear goal and path for the development of project management capability.Secondly,we set a project management capability evaluation index system according to the project management processes and key process areas.Moreover,we use the fuzzy mathematical theory to evaluate the project management capability maturity level.Finally,the large aircraft main manufacturer can choose the best practices based on the evaluation of the maturity level so as to reach the purpose of improving project management capability of the main manufacturer gradually.

Billions Lomon Created an Aircraft Carrier-grade Manufacturer

On October 28,'2016 Global Titanium Dioxide(Chloride Process)Application Forum & Lomon Billions Press Conference'opened in Zhengzhou.The one-year long Billions-Lomon merger project was formally completed.This signified the birth of Asia’s biggest and world fourth-ranking Titanium Dioxide enterprise.Chairman of Billions said at the

Research on uncertainty in measurement assisted alignment in aircraft assembly

Operations in assembling and joining large size aircraft components are changed to novel digital and flexible ways by digital measurement assisted alignment.Positions and orientations（P＆O）of aligned components are critical characters which assure geometrical positions and relationships of those components.Therefore,evaluating the P＆O of a component is considered necessary and critical for ensuring accuracy in aircraft assembly.Uncertainty of position and orientation（U-P＆O）,as a part of the evaluating result of P＆O,needs to be given for ensuring the integrity and credibility of the result;furthermore,U-P＆O is necessary for error tracing and quality evaluating of measurement assisted aircraft assembly.However,current research mainly focuses on the process integration of measurement with assembly,and usually ignores the uncertainty of measured result and its influence on quality evaluation.This paper focuses on the expression,analysis,and application of U-P＆O in measurement assisted alignment.The geometrical and algebraical connotations of U-P＆O are presented.Then,an analytical algorithm for evaluating the multi-dimensional U-P＆O is given,and the effect factors and characteristics of U-P＆O are discussed.Finally,U-P＆O is used to evaluate alignment in aircraft assembly for quality evaluating and improving.Cases are introduced with the methodology.

Inner wrinkling control in hydrodynamic deep drawing of an irregular surface part using drawbeads

Inner wrinkling phenomenon is more likely to develop during hydrodynamic deep drawing （HDD） of complicated component-forms due to the higher demand for controlling deformation sequences. Aiming at the problems in control of inner wrinkling for an irregular surface part featured with both concavity and convex, this research proposes an optimal design method of drawbead parameters to change the material flow. According to theoretical analysis of the mechanism of inner wrinkling, optimizing cavity pressure only is unreasonable to form a wrinkle-free deep-drawn part, so semi-circular drawbeads are employed. The effects of layout and height of drawbeads on forming results are discussed, and a process window is established based on evaluation indicators including the anti-wrinkle coefficient and the minimum wall thickness. Experiments are carried out to validate the process window, and the wall thickness and the wrinkle height are measured and compared with numerical findings. The results show that the anti-wrinkle ability of drawbeads weakens with increasing oblique angle and distance from the die center, while the wall thickness increases with increasing oblique angle and distance, and the inner wrinkling can be completely suppressed by drawbeads arranged in zones I and II with optimum penetration.