基于VC++6.0的双盘式渐开线测试仪齿廓偏差测量控制系统设计

双盘式渐开线测试仪是测量标准齿轮渐开线齿廓的高精度仪器之一.简要介绍了双盘式渐开线测试仪的测量原理和基于VC 6.0的测量控制系统设计.系统由测量软件控制研华数据采集卡PCL-818L采集测量值,通过串口将采集数据传给计算机,最后由软件进行数据处理得到被测齿轮的齿廓偏差并绘制出齿廓偏差曲线.     

基于偏差分析的航空装备软件费用控制方法

针对航空装备软件费用控制与管理问题,提出了一种基于偏差分析的费用控制策略,给出了重大偏差标准设定方法,将挣值管理引入到航空装备软件费用监控中,解决了软件费用与进度的控制问题。研究结果表明,基于挣值管理的方法可准确掌握项目费用和进度的实施情况,当费用或进度偏离计划时,能够及时发现项目研发中存在的问题并采取策略进行调整,有效实现了软件费用和进度的监控与管理。     

一种基于CAD技术的渐开线齿轮齿廓构建方法

本文分析了目前常用的渐开线齿轮齿廓创建方法的不足之处。根据渐开线的形成原理,运用ADAMS软件,采用小步长、多迭代和多控制点的方法,创建出高质量、高精度的渐开线齿廓线。通过ADAMS与其他CAD造型软件的接口,可以进行渐开线齿轮的实体设计。     

基于ISO 13849-1标准的安全继电器

EN 954-1标准概括了控制系统与安全相关部分设计的一般性原则。但是,随着电子和可编程电子系统在机械设备应用领域的广泛应用,系统变得越来越复杂,控制系统以及其相关子系统的设计有了更新、更高的要求,因此需要一种新标准来适应系统这种新的要求,ISO 13849-1正是基于此原因而产生。     

渐开线直齿圆柱齿轮创建方法的探讨

本文作者介绍了两种分别以Pro／ENGINEER和CAXA软件为平台的渐开线直齿圆柱齿轮三维实体造型方法,利用这两种方法可提高直齿圆柱齿轮的三维造型速度和设计效率。     

基于电子齿轮功能的齿轮轴-轴跟踪测量法

研究了伺服驱动器的电子齿轮功能和渐开线直齿圆柱齿轮齿廓偏差的测量原理,提出了一种基于电子齿轮功能的轴-轴跟踪测量齿廓偏差的方法,降低了数控系统的跟踪误差使仪器的测量精度得以提高,解决了标准轨迹法对控制系统本身性能及坐标轴之间的协调性要求较高,以及测头跟踪测量法自动循环测量实现困难的弊端。     

基于形式化方法的测试驱动开发研究

对测试驱动开发中测试用例的自动生成和管理问题进行了研究,并时现有方法进行了分析和比较.给出了一种基于形式化方法的测试用例生成和管理方案.该方案通过形式化语言描述软件规约,并通过相应工具生成和管理测试用例,从而提高了测试驱动开发的效率.最后给出了该方案在极限编程各个开发阶段的应用.     

基于0-1属性矩阵的矩阵压缩存贮方法研究

在矩阵压缩存贮中引入0-1属性矩阵的概念,并在0-1矩阵的基础上给出了利用一维动态数组以及二维动态数组和一维动态数组混合存贮稀疏矩阵的寻址公式,该存贮方法为快速有效的存贮方法,节约了内存空间。     

基于SVM的0-1序列生成器

提出一种0-1序列生成器的设计方法。该方法通过Logistic映射得到一组对初始值具有敏感性、快速衰减的自相关性、长期不可预测性和伪随机性的随机序列;利用SVM对随机序列进行粗粒化,由于SVM的确定性和不改变随机序列的时序性,生成0-1随机序列。理论研究和数值模拟表明,该序列发生器具有良好的随机性,并且易于实现。     

基于蚁群算法的多维0-1背包问题的研究

系统地阐述了蚁群算法,并对它进行改进、优化。将蚁群算法应用于求解多维0-1背包问题,提出一种求解多维0-1背包问题的算法——多维0-1背包问题蚁群算法。它大大减少了蚁群算法的搜索时间,有效改善了蚁群算法易于过早地收敛于非最优解的缺陷。仿真实验取得了较好的结果。     

Whole-body vibration exposure experienced by motorcycle riders – An evaluation according to ISO 2631-1 and ISO 2631-5 standards

Riders of twelve motorcycles, comprising 6 full-scale motorbikes and 6 motor-scooters, and 5 sedan vehicles, performed test runs on a 20.6 km paved road composed of 5 km, 5 km, and 10.6 km of rural, provincial and urban routes, respectively. Each test run of motorcycle was separately performed under speed limits of 55 km/h and 40 km/h. Tri-axial accelerations of whole-body vibration (WBV) were obtained by using a seat pad and a portable data logger, and the driver's view was videotaped with a portable media recorder. Root mean square (RMS) acceleration, 8-h estimated vibration dose value (VDV₍₈₎) and 8-h estimated daily dose of static compression dose (S_ed) were determined from the collected data in accordance with ISO 2631-1 and ISO 2631-5 standards. Experimental results indicate that the WBV values of the sedan vehicle drivers have low RMS, VDV₍₈₎ and S_ed values (RMS 0.27–0.32 m/s²; VDV₍₈₎ 6.3–8.3 m/s^1.75; S_ed 0.21–0.26 MPa). However, over 90% of the motorcycle riders had VDV₍₈₎ (mean 23.5 m/s^1.75) exceeding the upper boundary of health guidance caution zone (17 m/s^1.75) recommended by ISO 2631-1, or had S_ed (mean 1.17 MPa) exceeding the value associated with a high probability of adverse health effects (0.8 MPa) recommended by ISO 2631-5. Over 50% of the motorcycle riders reached these boundary values for VDV and S_e in less than 2 h. The WBV exposure levels of the full-scale motorbikes riders and motor-scooter riders were not significantly different. However, the RMS and VDV₍₈₎ values of motorcycle riders indicate significant roadway effect (p < 0.001), while their S_ed values indicate significant speed limit effect (p < 0.05). This study concludes that the WBV exposure levels of common motorcycle riders are distinctively higher than those of sedans, even on a regular paved road. The impact on health of WBV exposure in motorcycle riders should be carefully addressed with reference to ISO 2631-1 and ISO 2631-5.

Relevance to industry

This study compares the predicted health risks of motorcycle riders according to ISO 2631-1 and ISO 2631-5 standards. Experimental data suggest that the vibration dose value of ISO 2631-1 and daily dose of equivalent static compression stress of ISO 2631-5 have roughly equivalent boundaries for probable health effects.     

The W-Process for Software Product Evaluation: A Method for Goal-Oriented Implementation of the ISO 14598 Standard

The importance of software product evaluations will grow with the awareness of the need for better software quality. The process to conduct such evaluations is crucial to get evaluation results that can be applied and meet customers' expectations. This paper reviews a well-known evaluation process: the ISO 14598 standard. The review focuses on the difficulties in selecting and evaluating the appropriate evaluation techniques. The review shows that the standard has problems in applying evaluation processes in practice due to insufficient attention to goal definition and to relationships between activities being implicit. Also, the standard ignores the trade-off between goals and resources and pays insufficient attention to feedback. To address these deficiencies, the W-process is proposed. It extends the standard through an improved process structure and additional guidelines.     

Evaluation of whole-body vibration exposure experienced by operators of a compact wheel loader according to ISO 2631-1:1997 and ISO 2631-5:2004

Limited studies were carried out to evaluate the whole-body vibration (WBV) exposure experienced by operators of compact wheel loaders (CWLs) according to ISO 2631-1:1997. No study was carried out according to ISO 2631-5:2004. Therefore, evaluation of the WBV exposure using these two standards was carried out and the results were compared in this study. Tri-axial accelerations were measured at the seat/operator interface on a medium-sized CWL. The vibration measurements were carried out in ten different operations, such as the V-cycle and the driving over different road surfaces. In order to represent the daily work of the CWL, seven scenarios were proposed. These scenarios are comprised of V-cycle and driving over different distances. The evaluation result according to ISO 2631-1:1997 showed that the permitted daily exposure durations of six scenarios estimated using the vibration dose value (VDV) method did not exceed 8 h. For the pure V-cycle and the combination of V-cycle and slow driving, the permitted daily exposure durations estimated according to ISO 2631-1:1997 were shorter than those estimated according to ISO 2631-5:2004. However, for the combination of V-cycle and fast driving, the permitted daily exposure durations estimated according to ISO 2631-1:1997 were longer than those estimated according to ISO 2631-5:2004.Relevance to industryThis study evaluated the effect of WBV arising from a CWL on human health according to ISO 2631-1:1997 and ISO 2631-5:2004. Evaluation results show that boundaries of the health guidance caution zone in ISO 2631-5:2004 are higher than those in ISO 2631-1:1997.     

基于证据理论的软件功能可信度的评估

证据理论是一种经典的处理不确定性信息和解决信息不完整的方法,软件属性和质量因子大都具有模糊性,很多因子不能用确定的数值表示。基于ISO/IEC9126质量模型中给出的27个软件子特性,利用证据理论及其合成规则计算了软件功能可信度,并给出了实例说明该方法的有效性。最后,总结了该方法的不足。     

一种航空机载嵌入式软件安全性评价方法研究

机载嵌入式软件是航空电子系统的重要组成部分,其安全性直接关系到飞行安全。由于软件安全性包含的范围较广,对安全性的评价往往周期长、结果不明确。针对嵌入式软件安全性评价的难题,在软件的整个生命周期采用分类模糊综合评价方法,建立了评价模型,提出了一种嵌入式软件安全性评价方法,在软件生命周期的5个阶段提出了59种评价元素,每种评价元素均反应出软件在每个阶段的关键活动。在各个阶段选择相关项目人员对每个元素进行评价,并依据计算公式得出软件安全分值。通过工程实践证明,该方法切实可用,评价过程相比传统的方法节约了时间,评价结果准确、直观,为航空机载嵌入式软件尤其是型号软件的安全性评价提供了一种新方法,为软件总体质量的评价和软件安全性的改进方向提供支撑。     

基于模糊理论的教学软件质量评估模型

通过分析目前国内外使用的几种评估软件质量的方法,结合教学软件具体实际和综合考虑,提出利用模糊理论评估教学软件质量的模型,改善传统评估方法中不合理和复杂性的弊端,并能方便快捷地得出科学、准确、客观的评估结果,在评估电子商务模拟教学软件实际应用中有良好的运行效果.     

基于未确知测度的软件可靠性定性评价

分析了软件可靠性定性评价中的不确定性,结合未确知数学理论,建立了软件可靠性评价指标体系,提出可靠性评分、不确定性量化方法和置信度准则,构造软件可靠性定性评价未确知测度模型,将该方法应用在惯性导航软件系统的可靠性定性评价中,验证了该模型的可用性和有效性。     

基于L1自适应的无人飞艇俯仰姿态控制器设计

针对无人飞艇模型复杂的非线性特性和不确定因素干扰姿态控制的问题,采用L1自适应控制方法构建不确定参数模型,进行无人飞艇的纵向姿态控制律设计,提高了飞艇纵向控制抗扰能力。通过建立无人飞艇俯仰运动模型,结合LQR对系统进行反馈配置以改善其稳定性,并将系统配置为典型L1被控对象形式,利用投影算子引入不确定参数对模型修正,得到自适应的控制算法。结果表明,基于反馈优化配置的L1自适应控制算法能够使无人飞艇的俯仰得到良好的瞬态和稳态性能,对系统参数摄动具有较强的鲁棒性,可适用于无人飞艇的姿态控制。     

基于BP人工神经网络的软件质量评估

针对软件质量评估的课题,提出了一种基于BP人工神经网络的软件质量评估方法,提高软件质量评估的准确性.首先,论文介绍了人工神经网络的基本原理和软件质量评估的基本过程.然后选取适当软件质量特征构建基于BP人工神经网络的评估体系,分别进行BP网络学习和验证数据测试的实验.通过测试得到的数据结果,证明该方法能够准确地评估软件质量.     

基于风险因子的软件项目风险评价模型

以软件项目的启动过程、计划过程、执行过程、控制过程、收尾过程和项目综合管理能力作为六个风险因子,提出了一个风险评价模型,总结了78个风险指标,依据模型计算出各种风险对进度、成本、范围和质量的综合影响。