基于改进TOPSIS的航空发动机维修性评估方法

针对民用航空发动机维修性设计方案优选时缺少对定量指标评估的问题,提出一种基于改进TOPSIS的维修性评估方法;该方法首先根据民用航空发动机的设计准则、相关维修标准和持续适航的约束,构建定性的维修性指标体系和定量的维修性指标体系;以层次分析法和熵权法相结合的方式确定各指标的权重系数;通过建立虚拟仿真维护环境计算出各定量指标,在此基础上,运用改进TOPSIS法对航空发动机不同维修性设计方案的维修性进行综合评估;实验验证提出的方法能够得出最佳的维修性设计方案,可为民用航空发动机的维修性评估提供参考。     

A method for integrating ergonomics analysis into maintainability design in a virtual environment

Designers must consider human factors/ergonomics when making decisions from the perspective of maintainability. As an important aspect of maintainability, maintenance space should be made adequate at the design stage to achieve a convenient maintenance process. A maintenance space evaluation method that considers ergonomics is proposed in this study. By comparing free swept volumes and constrained swept volumes in a virtual environment, maintenance space could be evaluated quantitatively and objectively. The results of the evaluation are obtained by combining the principles of ergonomics and maintainability. These results can help designers improve product design such that it fits ergonomics and maintainability requirements. A case study is introduced at the end of this paper to demonstrate the feasibility of the proposed method in efficiently evaluating the maintenance space based on the layout design of the product components in the design stage.Relevant to industryFor a large number of disasters caused by human errors in current industry, the result of this study contributes a guide to fully consider human factors in maintainability design through virtual environment and is beneficial to designers and engineers of industrial application fields.     

基于维修流程框图的维修时间仿真研究

武器系统的维修性是一个重要的性能指标,维修时间是维修性的主要定量参数、是影响装备可用度、战备完好率的重要因素。通过分析常用的维修性指标和维修性预计方法,提出了基于维修流程框图的维修时间仿真方法。维修流程框图是用于表示维修活动的步骤,一般比较复杂,甚至有可能形成大的网络,基于这种情况,建立了基于维修流程框图的自动化维修时间仿真方法。其对武器系统的维修性设计、预计和分析有较好的作用,利用这种维修时间仿真方法开发的软件系统也有一定的实用价值。     

Compensation-based methodology for maintenance time prediction in a virtual environment

This study presents a novel compensation-based methodology for maintenance time prediction in a virtual environment during the early stage of product design. According to the work procedure in assigning maintenance tasks, a maintenance process simulation is generated on the virtual maintenance platform by following the simulation principle. The basic compensation time or ratio is acquired by analyzing the relationship between practical human motions and corresponding virtual human motions. After that, the compensation principle is confirmed based on the generated simulation principle. Finally, the simulation time and compensation time are approached according to the compensation model to obtain the predicted time. The obtained predicted time of several cases are accurate to a certain extent compared with feedback information.     

特种车辆维修空间可达性评价方法研究

可达性作为维修性的定性指标,缺少定量评价的方法。传统方法只针对装备的整体进行定性评价,不能对不同的等级维修和单个维修动作进行评价。通过对维修性设计中的结构性因素进行分析,得到了空间可达性的主要影响因素。在虚拟维修仿真平台的基础上对工具旋转角度和作业空间比进行了量化评分,给出了针对维修作业过程中单个零部件拆卸的空间可达性评价方法。单个动作评价方法为等级维修的整体空间可达性评价提供了数据基础,并为新型特种车辆的维修方案论证和研制的空间可达性评价提供了手段。     

Motion-based method for estimating time required to attach self-adhesive insulators

A self-adhesive insulator is a component of a home appliance that is used to suppress vibration or prevent humidity affecting the internal parts of the appliance. There is a wide range of types and designs available, allowing them to be applied to areas having different shapes. At the design stage, once an insulator design has been developed sufficiently to identify its dimensions and features, the attaching time and baseline cost must be estimated with reasonable accuracy to enable a comparison of vendor quotes. However, the current estimation method is not sufficiently accurate in terms of the baseline cost. This paper presents a motion-based time-estimating scheme with which the time required for the attachment of such insulators can be calculated more accurately. The scheme has been developed by analyzing the motions needed to attach 350 insulators and then designating representative motions and their time values. For this purpose, a modular arrangement of predetermined time standards (MODAPTS) is adopted. Motion-based time-estimation method is useful in terms of simplicity and accuracy. It enables design engineers to estimate the time required for the attachment based only on a drawing of the insulator and a few MODAPTS rules. Estimates made with this method should vary from the actual value by no more than 9.5%.     

基于虚拟现实的动车组维修性验证系统研究与设计

针对动车组维修性验证方法不足的问题,提出了采用虚拟仿真手段对维修性进行验证的方法;结合动车组系统的特点,对基于虚拟现实的动车组维修性验证系统进行了方案设计,给出了维修性验证具体流程,研究了三维虚拟样机建模的基本方法;虚拟维修性验证系统有效提高了动车组维修性设计效率,缩短了研制周期,是一种实现动车组维修性并行优化设计的有效方法。     

Proactive and visual approach for product maintainability design

Maintainability design, as a vital element in product design, is generally conducted after the physical or virtual prototype is done, and this design way always accompanies with the characters of lag, passiveness, subjectivity and lack of relevance. And even design flaws are exposed based on corresponding maintainability analysis, the improvements are hardly finished owing to various practical difficulties. This paper proposed a novel proactive maintainability design method. Based on the maintainability and functionability/structurability (F/S) factors of the product first, a “many to many” mapping relationship between maintainability and F/S spaces is established, in which quantitative assessment and visualization representation are two aspects. Separately, the quantitative assessment provides an objective and precise result of relationship confirmation, and the visualization representation brings a comprehensive and intuitive way for maintainability and F/S designers. Finally, the case study section shows the availability and effectiveness of the methodology by verification and comparison. The proposed methodology considers maintainability affection on F/S just from the start point of product design. Hence, compared with the physical prototype and virtual prototype approach, the implementation of the proposed methodology can make maintainability design and functional/structural design to be conducted almost simultaneously.     

沉浸式虚拟维修仿真及其应用

文中给出了沉浸式虚拟维修仿真系统的框架,从样机建模和交互技术两个方面对其关键技术进行了研究。提出了虚拟维修样机的概念,通过定义样机部件的约束运动和交互特征来实现其要求的功能。而交互技术则主要集中在抓取、运动控制和防穿越处理上。对系统在维修性设计分析(核查)、维修程序确认和辅助维修训练中的应用进行了说明。建立了基于Jack系统的沉浸式虚拟维修仿真原型系统,并以某机构的拆装为例对其进行了初步的应用验证。     

Incorporating motion analysis technology into modular arrangement of predetermined time standard (MODAPTS)

Implementing new strategies to achieve higher work efficiency is essential to improve productivity during a monotonous and exhausting work task. The Modular Arrangement of Predetermined Time Standard (MODAPTS) concept is widely used to achieve these goals in the field of human factors. However, MODAPTS is very complicated with regard to assisting engineers in understanding the system because it requires much learning time and even longer hours of effort during coding manual process. To help overcome the deficiency of the traditional method, a modern method for motion analysis, called PCA-based motion analysis, is proposed in this paper. Motion analysis has already been the main approach to analyze human motion in sports science and biometrics, but it is still unfamiliar for human factors analysts. This paper discusses a potential connection between motion analysis technology and MODAPTS analysis, which would help make MODAPTS more efficient and reliable. In the experiment, fifteen participants were asked to watch a motion sequence and then analyze the motion sequence using MODAPTS. Meanwhile, the motion-captured data were carefully segmented into motion elements with the PCA approach. A comparison of the motion segmentation contrast was made between MODAPTS analysis and automatic motion element segmentation using PCA. The accuracy rate of segmentation by the PCA approach was 80.08%, and the primitive frames of the two methods indicated that the segmentation is acceptable. In addition, the PCA-based motion analysis showed a substantial time-saving difference in the processing time, which was only approximately 3 min for motion analysis versus over 1 h for MODAPTS. Motion analysis provides high efficiency and reliability for motion segmentation and sufficient precision compared to the results using MODAPTS. Moreover, assessment of the operations’ rationality and optimization of the production line design instead of repetitive work on motion segmentation is the focus. Integrating motion analysis technology into traditional MODAPTS is a useful advancement that permits significant progress for human factors analysis. In the future, the accuracy of the automatic segmentation techniques should be improved.Relevance to industryIn recent years, motion analysis technology has become increasingly popular in various fields but not in the field of human factors. The automatic method presented in this paper may allow industrial workers to optimize unreasonable motion, remove unnecessary operations and formulate the standard working time more conveniently and accurately.     

一个面向维修工程的虚拟人素分析系统软件框架

在工业产品、武器装备的维修性设计中，用虚拟现实技术进行人素分析，可以有效地提高产品的可维修性。该文提出了一个虚拟人素分析软件框架，并在此基础上，基于虚拟人平台—Jack，设计实现了一个虚拟人素分析系统。该系统根据给定的虚拟人体模型和虚拟样机进行人素分析并产生人素分析报告。该软件实现了维修仿真过程建模，以及基于维修仿真过程的人素分析功能，给用户提供了一个高效的分析环境。软件系统的应用实例研究表明，该文提出的软件框架是合理有效的。     

Code smells as system-level indicators of maintainability: An empirical study

Context

Code smells are manifestations of design flaws that can degrade code maintainability. So far, no research has investigated if these indicators are useful for conducting system-level maintainability evaluations.

Aim

The research in this paper investigates the potential of code smells to reflect system-level indicators of maintainability.

Method

We evaluated four medium-sized Java systems using code smells and compared the results against previous evaluations on the same systems based on expert judgment and the Chidamber and Kemerer suite of metrics. The systems were maintained over a period of up to 4 weeks. During maintenance, effort (person-hours) and number of defects were measured to validate the different evaluation approaches.

Results

Most code smells are strongly influenced by size; consequently code smells are not good indicators for comparing the maintainability of systems differing greatly in size. Also, from the comparison of the different evaluation approaches, expert judgment was found as the most accurate and flexible since it considered effects due to the system's size and complexity and could adapt to different maintenance scenarios.

Conclusion

Code smell approaches show promise as indicators of the need for maintenance in a way that other purely metric-based approaches lack.     

基于VR技术的虚拟维修仿真系统设计与应用

针对产品并行研发模式下的维修性问题,将虚拟现实技术引入到产品维修仿真中,即在计算机生成的虚拟现实环境中对产品进行维修仿真分析。文中以单通道被动立体投影系统为虚拟现实环境,以DELMIA、VRCO VisTool、CDVI、Pro/E等软件为虚拟现实软件系统,构建了一个虚拟维修系统,阐述了系统中VR外设集成、环境建模与数据转换、碰撞检测、人机工效和立体显示等关键技术。最后以某型雷达天线转台维修为例,验证了虚拟维修的有效性。     

基于CBR和RBR的维修性设计技术智能化

结合维修性设计过程分析和人类处理问题的思维方式,依据维修性设计技术的两大指导文献(《维修性设计准则》与《维修性设计技术案例汇编》),分析了RBR和CBR技术的优缺点,给出了基于RBR和CBR混合推理的维修性设计技术智能化的框架结构。     

虚拟维修性分析系统的研究

从维修性设计的需求入手，指出了开展虚拟维修性分析系统研究的必要性，提出了虚拟维修性分析系统的结构框架，描述了软硬件配置，分析了系统的运行机制，并对几个关键技术问题进行了讨论，最后提出了需进一步研究的工作。     

沉浸式虚拟维修仿真系统及其实现

给出了沉浸式虚拟维修仿真系统的框架,从样机建模和交互技术两个方面对其关键技术进行了研究．提出了虚拟维修样机的概念,通过定义样机部件的约束运动和交互特征来实现其所要求功能,而交互技术则主要集中在抓取和防穿越处理上．建立了基于Jack系统的沉浸式虚拟维修仿真原型系统,并以某机构的拆装为例对其进行了初步的应用验证。     

基于多模型的能源组件维修性建模与仿真研究

某激光装置能源组件是其关键组件,该组件具有随机劣化失效特点,其部件失效类型多,维修类型和维修策略也比较复杂,现有的基于单一模型和解析方法的系统维修性建模与分析方法难以解决其维修性设计与分析问题。本文采用多模型集成的维修性建模与仿真方法,解决能源组件维修性建模与分析问题。其中,采用故障树模型描述能源组件系统级可靠性,采用SPNAT模型描述各部件的失效过程和维修决策,并基于"Join/Replicate"操作进行模型集成,通过报酬结构定义组件的维修性指标。仿真结果表明,基于多模型集成的维修性建模与仿真方法,是解决能源组件这样的复杂产品维修方案设计与分析的有效途径。     

Safety-based availability assessment at design stage

The availability of a system or equipment is one of the crucial characteristics that measures the customer satisfaction and strongly influences his final choice decision between concurrent products. The aim of this work is to provide an approach to improve the products availability assessment by taking into account the safety criteria by considering the use situations at design stage. Our work focuses on the routine design of complex products. The availability is often simply estimated considering reliability and maintainability. Basically, the intrinsic availability is the probability that it is operating satisfactorily at any point in time when used under conditions stated by design specifications. The time considered includes operating time and active repair time. Thus, intrinsic availability excludes from consideration all other times in the product lifecycle such as: accident management time, storage time, administrative time or logistic time. But many studies show that the loss of availability performance is also due to accidents that occur in different unforeseeable utilization situations. This engenders stops of the system to ensure the users safety according to standards recommendations. In this purpose, we consider the structural product architecture and the different use cases that correspond to the operational states and downtimes due to stop events that may happen during the utilization like failures, maintenance tasks and accidents. Then, we propose a product behavioral analysis including the use cases to describe interactions between the product and users or maintenance operators. We use Markov chains to model the use cases corresponding to operating time (OT), maintenance time (MT) and preparing time after accidents (RT). Then these three parameters are considered to specify a generic approach to improve the availability assessment. Such an approach provides the traceability of the product behavior along its lifecycle. In this way, the main causes of stop can be identified and this may guide the designer for improving the availability of the product future versions. To validate our approach, an application is presented considering a printing line. The comparison of our simulation considering an industrial case study shows a good agreement about the influence of safety on the availability.     

维修性预计工程化及计算机化研究

针对维修性设计的工程全过程,分析了各种预计方法,探讨了维修性预计的工程化与计算机化的实现;引入维修活动智能分解模块,并进行了初步尝试：在预计方法２０２（功能层次预计法）改进的基础上,并综合其他方法,在计算机上的得以实现（在ＰＣ机Ｗｉｎｄｏｗｓ环境下使用Ｃ＋＋语言实现）。     

基于案例的维修性智能设计技术研究

产品维修性的设计长期以来依赖于积累的经验。文章在大量收集维修性设计技术案例的基础上,有针对性的制作多媒体信息材料。提出了基于实例的智能设计技术并实现了计算机辅助工程系统,详细阐明了该系统的组成、结构、功能,以及所采用的基于案例的推理技术、数据采掘技术。