在电气线路互联系统(EWIS)的线束通道上,重要的线束捆常用P型金属带垫卡箍固定.线束捆直径是EWIS设计和装配的基础计算参数,不仅决定卡箍的规格,而且影响卡箍与线束捆的装配质量、线束通道横截面和穿过隔板或结构件的开孔大小.目前已有直径计算主要是针对单分支最简单的线束捆,且不能给出线束截面几何排布.建立了线束捆直径计算的数学模型,模型求解基于二维不等圆Packing问题的启发式计算方法,不仅可以得到线束捆直径,而且可以计算出线束捆截面分支、分支内线芯的几何格局.在此基础上,提出了线束制造和总装装配工艺应遵循的三个原则,包括降维原则、分层原则和正圆原则.

电气线路互联系统(EWIS)是为飞机各系统传输电能的重要系统.适航标准中系统分离规则要求通过物理分离将EWIS发生故障时对飞机产生的危害降到最低.规则评判对象是已安装的EWIS,其主体是已安装的线束.得到这些线束的过程是线束综合,其关键技术就是线束通道规划,但目前相关研究尚未建立线束通道规划的原则和标准.基于系统分离规则探索线束通道规划的一般规律,创新性工作包括:建立了线束通道分离的定量表达,将对每个EWIS的物理分离要求转化为对区域线束通道的要求,提出线束通道的实质是一类导线在区域内敷设的唯一主通道;提出一种利用隔离代码从系统分离规则确定区域内线束通道数量和类型的方法;建立了线束通道规划原则,为EWIS系统满足系统分离规则定性评估提供了方法与依据.

飞机线束是电气线路互联系统的重要组成部分,飞机线束敷设的合理性、固定和连接的正确性、可靠性都将影响飞机的正常工作.而获取飞机线束的设计数据可以更有效的完成飞机线束的制造和敷设,因此对飞机线束的数据提取具有重要意义.本文对CATIA进行二次开发,并对 CATIA 提供的关于点数据提取的二次开发接口函数的功能进行了探索,找出了数据提取函数及途径,最终,通过CAA完成了数据提取程序的编制,并在此基础上对设计数据进行结构识别.

线束设计过程中,电缆成束直径的计算是不可缺少的步骤之一.通过对常用的圆形非等芯电缆成束直径进行推导,得出了电缆直径与成束直径的公式关系,应用MATLAB软件的GUI模块做出人机交互平台.在该平台下用户可以通过输入电缆直径参数,得出电缆的排布以及成束直径的值,实现了用计算机快速、直观、准确地计算圆形非等芯电缆成束直径的方法,为线束设计人员提供了有力帮助.

为了提高飞机线束的装配效率和装配质量,提出了确定线束装配定位方法的总体流程,通过提取线柬3D模型数据信息,建立了基于父子分支的线束层次数据链模型.提出一种新的线束展平角计算方法,并按照线束层次模型将线束进行展平,最终在2D展平图上确定出线束安装定位标记的位置,通过编程在MATLAB GUI中搭建了装配定位平台,实验表明,该方法能够在制造出的线束上进行标记,可以指导生产以及现场装配.

With cable as vital part in the electromechanical system, its quality directly has influence on its laying quality. In recent years, the virtual cable assembly technology is getting more and more attention. Compared with the traditional cable planning, cable modeling and assembly simulation in the virtual reality environment can shorten the assembly cycle, reduce the costs and improve the quality and efficiency. The mechanical and electrical products are imported into the virtual platform, the cable is modeled by B-spline curve method, In the virtual platform, the model can be used to detect and calculate the interference of the cable and to judge whether the cable laying is reasonable or not.

Abstract:The cable harness branches assembled in aircrafts can be separated by fix points into a number of cable harnesses between the adjacent fix points. One kind of these cable harnesses between the adjacent fix points, which has the assembly feature: one fix point being a mechanical protection and the other fix point being electrical connector, is defined as the end cable harness between the adjacent fix points(''the end cable harness'' for short) in this paper. The principle of determining the lengths of cable harness branches in prototype was revealed, it is proposed that the unit lengths of determining cable harness branches in prototype are lengths of cable harnesses between the adjacent fix points. And the process for assembly workers to determine the length of one cable harness between the adjacent fix points was abstracted as a kind of iterative approach in which its length was determined by justifying whether the process geometrical requirement and the process clearance requirement could be met or not under a given possible lengths. On the basis of that, the length model of the end cable harness was developed to calculate its maximum and minimum length values in the computer platform. To solve the model, the preliminary geometry model for this kind of cable harness was proposed by 6R robot arms, in which the end cable harness’s stiffness could be simulated by adjusting the ratio of lengths of the six rods. Then based on the minimum curve energy method, the refined geometric model was proposed where the center line of the main body of the preliminary geometry was refined to an arc with common end points and same length, the gap detecting precision was improved. Finally, the length model of the end cable harness was programmed in VR environment and the calculating result of an entire example was verified by experiments.

For the strong nonlinear and variable parameters properties of high bypass ratio turbofan engine,an adaptive PID control method based on optimized extreme learning machine( ELM) was proposed to predict the engine's parameters. To improve the prediction accuracy and the real-time property of ELM,an improved Firefly algorithm( IFA) for multi-peak optimization was adopted to optimize the network parameters of the ELM,and formed an optimized ELM training method IFA-ELM. Under the premise of ensuring prediction accuracy,the algorithm effectively simplified the network scale and improved its generalization capability.The engine fan speed prediction model was built by this algorithm,and gradient descent method was adopted to adjust the PID parameters online based on the model to improve the dynamic performance of engine. Digital simulation results show that compared with conventional PID control,IFA-ELM based adaptive PID method shortens the settling time by 0. 2 ~ 1. 4 s,and reduces the overshoot by 0. 2% ~ 1. 5%,which demonstrates the effectiveness of the proposed control method.

Aircraft cable harness virtual assembly technology has an important influence on improving the efficiency of the aircraft assembly and performance of the machine. Modeling on aircraft cable harness is elementary and difficult. For aircraft cable harness elements, there are two kinds of the most common process constraints: suspension constraint and minimal bending constraint. The catenary theory has been proposed to model the elements under the suspension constraint accurately. For the elements under the minimal bending constraint the robot arm has been chosen to build the dynamic model to simulate the lying process. By controlling the parameters of the robot arm to meet the minimal bending radius requirement, the cables’ geometric changes can be realized in time. The Aircraft Cable Harness Virtual Assembly System (ACHVAS) has been developed and the cable harness elements under the two constraints have been demonstrated in the platform to verify effectiveness of the two models.

In order to improve the assembling efficiency and assembling quality of complex electromechanical products, it presents the method for deducing the assembling space ranks of harness from their assembling process information.It establishes the harness assembling space priority matrix to generate some assembling se-quences as the initial population, describes the fitness functions of harness assembling sequence from perspec-tives of assembling space ranks, the maximum diameter, the maximum length and number of branches.It devel-ops genetic algorithm, realizes the harness assembling sequence planning, obtains the optimal assembling se-quence and outputs the process information.

It is important for cable assembly to simulate the process planning on mechanical and electrical products in virtual environments.The planar static cable model was proposed according to the theory of catenary for cables to install under the suspended condition.To satisfy the real-time requirement for the cable assembly simulation,the planar cable model could be built rapidly by the algorithm analysis on its key parameters on condition that the cable length and two fixed endpoints of the cable were determined.Using the coordinate transformation method,the 3D cable assembly simulation model under the suspended condition could be gotten from the planar cable model,which is suitable for the environment platform.Using the cable assembly simulation model,the dynamic simulation for cables under the suspended condition could be realized by real-time getting cable’s terminal point coordinates and computer screen’s refreshing.At the same time,the tensions of each key point of cables could be computed to guide cable realistic assembly process.

In order to improve the efficiency of the cable assembly , it proposes a method for the modeling and simulation of cables in virtual environment according to their geometrical characteristics .A cable is modeled by rigid rod connected with joints like a robot manipulator arm .Based on a start and an end position and orientation of the cable , the method calculates the shape of the cable using the principle of inverse kinematics , uses the B-spline curve passing control points to smooth the cable models .This can factually simulate the true shape of ca-bles .The results show that the method is less time -consuming , and can realize the real-time simulation of de-formable cables in a virtual environment .

Pressure-pushing method of evaluation for adhesion strength of high performance coatings material and substrate is presented. This method, based on the pressure-testing device of high performance bond strength test sample patent, is one that the sample is cracking along the interface by putting the static load. According to the sample's stress boundary conditions, the formula of the adhesion strength is given. The surface coating/substrate interface stress distribution is analyzed by using the finite element method, which provides the theory basis for the correct evaluation of coating/substrate strength. The experiments are conducted on the strength of common coating substrate materials as well. All the results show that pushed method can test the adhesion strength of high performance coatings and substrate, whose data is smaller than the international standard and A STMC633-79. And the experimental data of the pushed method are free from the influence of random factors.

Auto-extracting of the constraint face information of parts is an important issue of virtual assembly.It presents a new approach of determining constraint faces of parts effectively,designs a new algorithm which may recognize constraint surfaces of parts and extracts automatically the constraint surfaces parameters.The example shows that the approach can meet the needs of assembly process planning and improve the efficiency of constraint recognition effectively.

Based on finite element method,it performs the mechanics evaluation of bonding strength between high-performance coating and substrate,proposes an improved test model to optimize its structure dimension.It analyzes the maximum tensile stress and the maximum shear stress on the coating and substrate interface,compares the influences of the metal strengthening slab of model and width of bonding-interface and thickness of coating on the interface bonding strength of coating-substrate.The results show that the model decreases obviously the maximum shear stress,changes the tensile stress in different systems.

A kind of model oriented assembly process simulation in WTK environment has been proposed. In the model, firstly, the assembly hierarchy of mechanical products can be presented clearly. Secondly, the assembly constraints between parts can be added to the model easily. At last, the assembly process information such as assembly sequence and path for each part can be recorded at real time in the model. Then, the converted method from PRO/E system to WTK environment about the mechanical product's design information including geometric models, product design hierarchies and constraints has been discussed, which makes for easier building the model in the virtual environment.

To ensure the precision and efficiency of virtual assembly operations,a novel assembly intention capturing algorithm was proposed.The expression of constraint model and modeling method in virtual assembly environment were presented.The concept of Constraint Element Bounding Box(CEBB)was introduced and its construction rules and method were also put forward.Intersection test between two CEBB was used as the portal of assembly intention capturing algorithm.Constraints multi-layer recognition rules were presented to define the constraint type based on the mapping relationship between constraint elements and degree of freedom.Then,to realize the intelligent constraint confirmation,constraint priority and comparison strategy of motion increment between constraint elements were proposed.The time cost function was introduced to estimate the computation efficiency of the algorithm.Finally,effectiveness of the proposed method was verified by an application example in an aerospace product.

It introduces a model for evaluating personal's capability based on rough sets and variable weight theory.Based on rough sets it simplifies and expresses the personal's capabilities,analyzes the problem of imbalance caused by invariable weight fuzzy synthesis evaluation,builds a local situation variable-weight model with punishing and inspiriting function.Comparing the results from two theories,it shows the importance of variable weight.

Different contents of nanometer Al2O3 particles (nano-Al2O3p) were added into laser cladding low Al NiCoCrAlY coatings to improve the oxidation resistance. The isothermal oxidation behavior of the coatings in air for 100 h at 1050 °C were investigated, and the effects and influencing mechanisms of nano-Al2O3p were discussed. The results showed that oxidation resistances of the nano-Al2O3p-added coatings are clearly better than that of the nano-Al2O3p-free one. The coating with 1 wt% nano-Al2O3p added showed the best performance. Its weight gain was 1.72 mg/cm2 after 100 h oxidation, which was only half the weight gain of the nano-Al2O3p-free coating. The duration required to reach the steady oxidation was only 1/20 that of the nano-Al2O3p-free coating, while the duration of the steady stage was 5 times longer than that of the nano-Al2O3p-free coating. With the addition of nano-Al2O3p, the oxidation resistance was improved by acceleration of Cr selective oxidation, inhibition of volatilization of Cr2O3 scales, improvement of oxide scale self-repairing capability, and blocking of micro channels for oxygen penetrating inwards. In particular, it was inferred that this blocking also has a significant effect on enhancing the oxidation resistance of other high temperature protective coatings such as non-volatile oxide scales.

According to the representations of assembly constraints of mechanical product models in commercial CAD platform, it presents a method for solving the acquisition and transformation of the assembly constraint data automatically to virtual assembly environment based on Pro/E. Based on the storage structure of assembly data in Pro/E models and the functional requirements in VR, it designs a multi-level data structure of assembly constraints for the virtual assembly environment. The result proves that the method can integrate assembly information automatically from Pro/E platform to VR, and increase the assembly efficiency in VR environment.