水田动力底盘逆向建模与质心验证——基于Geomagic Design X

针对目前农业机械仿真和优化模型精度不高的问题,提出了一种构建精确模型的逆向建模方法。应用光学扫描仪采集点云数据,基于Geomagic Design X处理点云数据并重构零部件模型,在SolidWorks中完成水田动力底盘的装配。以VP6D-CQ型水田动力底盘为例,将测得的实际质心位置与所建的模型质心位置进行比较,并对提出的逆向建模方法进行了试验验证以及误差分析。结果表明:总质量、x坐标、y坐标、z坐标的误差值分别为4.55%、3.62%、2.23%、4.81%,误差值均在5%内。此方法可构建准确的三维模型,为后续仿真优化数据精确性奠定了基础,与传统的研发相比较,可缩短农业机械研发周期、降低设计成本。

Lean Product Development Process with Design Verification Stages in the Value Stream of Automotive Industry

In the automotive industry, lean projects and innovation creation come to life by being updated under the control of systematic interdisciplinary process flows. The lean product development process that changes the shell, defined under the light of the variables created by the competitive conditions, is today measured by the value flow efficiency and the global market spread of the final product. Consequently, the lean product development approach, which aims to identify and purify all the wastes that do none value or create value to the system or cause burdens in the new product development process, is shaped by step-by-step approvals in the flow. In the main automotive industry company practices within the scope of the research (3 national, 3 international), the beginning of the concept of lean in design is to define and optimize the steps in the product development process under the value stream map. Therefore, the product function for which the customer has paid for, the function of the new product or the physical structure used to meet the needs in question, the comfort, life, experience, innovations of the scope that constitute the new product concept are planned and verified and implemented in the simplified automotive design stages at the beginning of the lean product development process. In this research, initial automotive design objectives and stages are at the focal point of the innovation and added value creation brought by the concept of “lean” approach. The research is modelled on the determination of steps that do not create added value together with the points where the flow circuits’ or stems, the process is devalued, the interdisciplinary holistic studies intensify, the information and delay begin and end in the sequential and simultaneous design validation step transition stages, which are examined under the lean approach. As a visual and virtual tool that enables the elaboration of nominal values such as the total duration of the design verification stages and the influence of interdisciplinary stakeholders or the test level of the product design with the new product added, it reveals the value flow or losses. Hence research;from innovation creation and new product design steps, which constitute the initial stages of the lean product development process, to design verification analysis, the efficiency of the automotive company processes within the scope of the research has been measured by comparing using lean automotive design techniques, methods and concepts.

The “Static” and “Dynamic” Design Verification Stages of the Lean Development Process: Automotive Industry

he design verification steps that take place in today’s automotive industry, which constitute the values of each successive or simultaneous phase in the new product development process, create a complex structure with the inclusion of each new technology and discipline. Therefore, step by step, each design verification phase definition in the flow contains important phase transition measurements or approval tolerances that ensure the simplicity and continuity of vehicle development processes. In addition, classification of design verification stages within the framework of this study or evaluation in two classes (static and dynamic) is a new approach, but it is a synthesis with the analysis of the new product development process. The vehicle’s basic structure, which constitutes the ergonomic and functional requirements of the vehicle in a static environment, takes into account the dynamic environment variables with crash or accident tests. Increasing new technology adaptations in the automotive industry have changed the new product development process that performs this function structurally and created the concept of design verification under consecutive or simultaneous process simplicity. From the autonomous driving to the use of alternative energy, possible accident scenarios and design verification phase transitions in the integration of parts and systems of the newly developed vehicle create a new structure that models and directs the lean product development process especially in the automotive industry in the coming days. In the lean product development process that takes place in the automotive industry, the design verification transition steps or the approval-control analysis of the development stages, which form a new and effective approach, are re-modeling the entire flow. Therefore, successful execution of design verification steps used in the control of new interdisciplinary product development phase transitions provides value creation.?Within the scope of this study, the effectiveness of the static and dynamic design verification steps, which are carried out in 5 global automotive companies included in the research, which constitute the stage transitions of the new product development process, has been measured. Apart from the design verification transition stages, the process variables that differ among the automotive companies involved in the research are excluded from the scope of this study. In other words, in field researches in the automotive industry, new vehicle design steps or basic engineering steps in the new product development process steps, while creating independent fixed variables, interdisciplinary collaborations, static and dynamic design verification transition stages they perform, or their sequence in the basic flow, is accepted as a dependent variable. Therefore, in the study, the positive effect of the automotive companies that included the static and dynamic design verification phase transition approvals in the lean product development process was investigated. Under the comparative analysis structure of the research, the effect of automotive companies, which accept international vehicle specifications as static design verification input, on market performance has been examined in depth. The detailed depth in the comparison analysis conducted under the second field studies of the study is due to the prediction of dynamic design verification stages to provide a high impact on the market performance, according to the static verification analysis. The new product development stages of the dependent variables were fixed and the flow-oriented?“effect”?of the independent variables in the basic process influenced by the design verification activities was analyzed under the new automotive industry company comparisons. In addition, the impact of the automotive design activities that make up the comparison analysis of the research on the scope of the lean product development stage and its effect on the basic process flow has been demonstrated competition-oriented. Therefore, sub-variables, options, criteria, results, which form a defined comparison problem, create basic test values that affect the problem.

Failure mechanism of directional roof cutting and design method optimization

Directional roof cutting(DRC)is one of the key techniques in non-pillar coal mining with self-formed entries(NCMSE)mining method.Due to the inability to accurately measure the expansion coefficient of the goaf rock mass,the implementation of this technology often encounters design challenges,leading to suboptimal results and increased costs.This paper establishes a structural analysis model of the goaf working face roof,revealing the failure mechanism of DRC,and clarifies the positive role of DRC in improving the stress of the roadway surrounding rock and reducing the subsidence of the roof through numerical simulation experiments.On this basis,the paper further analyses the roadway pressure and roof settlement under different DRC design heights,and ultimately proposes an optimized design method for the DRC height.The results indicate that the implementation of DRC can significantly optimize the stress environment of the working face roadway surrounding rock.At the same time,during the application of DRC,three scenarios may arise:insufficient,reasonable,and excessive DRC height.Insufficient height will significantly reduce the effectiveness of the technology,while excessive height has little impact on the implementation effect but will greatly increase construction costs and difficulty.Engineering verification shows that the optimized DRC design method proposed in this paper reduces the peak stress of the protective coal pillar in the roadway by 27.2%and the central subsidence of the roof by 41.8%,demonstrating excellent application results.This method provides technical support for the further promotion of NCMSE mining method.

Safety Design and Verification Analysis in the Satellite Development Stage

A safety design applies to every stage in a satellite system development life cycle to identify and analyze hazards in the satellite at a system level, eliminating or controlling various safety risks, while verifying the functions of the satellite system have safety characteristics, so as to optimize the satellite system for the best performance in terms of time and cost. This article comprehensively leverages such factors as satellite reliability, complexity and life cycle by considering the overall satellite safety work plan, hazard analysis, hazard sources, pyrotechnic devices and other module safety critical designs. Safety design measures were formulated to review and verify the effectiveness of system functions including a safe power supply to a satellite and pyrotechnic explosives to achieve the safety requirements of the satellite from a development stage. Safety design activities for each subsystem will ensure meeting the development requirements of the satellite system as a whole, and ensure the satellite system cannot be the cause of casualties, equipment damage, property loss, or have a health-threatening impact or detrimental impact on the environment.

低轨星座卫星快速开发与验证方案设计

针对低轨星座卫星快速开发与验证需求,提出试验星+工程星+接口验证平台(VPI)并行研制验证方案。通过工程星研制,对卫星结构、总装设计及供电主通道、推进贮供主通道等设计进行验证,支撑试验星设计优化与结构投产;VPI对星上电子单机接口、星上软件等进行迭代验证。通过试验星研制,对低轨星座卫星功能性能全面验证,确定星座卫星基线。该方案经多颗卫星实施验证,有效提高了低轨星座卫星验证效率。

落石被动柔性防护网非线性静力设计方法及验证

被动柔性防护网是一种常见的落石灾害防治措施。针对当前落石被动柔性防护网尚无适用的工程化设计方法的现状,以非线性计算过程中结构内能与设计防护能级相等作为加载完成的判别准则,建立了落石被动柔性防护网的非线性静力设计方法。基于LS-DYNA对250~5000 kJ共8种常用能级的被动柔性防护网开展非线性动力分析,明确了冲击力的分布范围及相对大小,形成了适用于不同能级落石被动柔性防护网非线性静力设计的荷载模式。为了有效模拟被动柔性防护网特殊的受力特征,开发了由索单元与受拉弹簧单元组成的非线性耗能单元用于耗能器模拟,开发了内部由多段索单元组成的滑移索单元用于滑移边界以及网环单元模拟。基于对网片冲击试验的反演和3500 kJ被动柔性防护网的设计及足尺冲击试验检验,验证了所提出的落石被动柔性防护网非线性静力设计方法的有效性。

空间站机械臂末端执行器用导轨设计与验证

针对滚珠直线导轨用于空间机构时的空间环境适应性问题,提出了空间机构用导轨设计方案,经导轨地面试验和产品在轨试验验证,该设计方案可以满足在轨使用要求,实现了导轨在真空、高低温等空间复杂环境下的长寿命应用.以空间站机械臂末端执行器用滚珠直线导轨研制为例,开展了导轨设计,并进行了导轨试验验证,确定了导轨采用滚珠溅射沉积MoS_(2)复合薄膜的固体润滑方案,间隙为0.04~0.05 mm,满足末端执行器在轨工作2000次以上的使用寿命要求.通过末端导轨试验可知,固体润滑的导轨载荷能力和使用寿命均显著下降,在空间机构用导轨研制过程中,须进行专项寿命试验,以验证导轨能否满足在轨使用要求.

无人集群体系设计与仿真评估方法

无人集群作战正在成为一种改变战争形态的新型作战样式。针对当前无人装备试验相对独立、缺乏一体化闭环设计与集成验证手段的问题,提出了一种体系设计与仿真评估方法。该方法包含了作战概念建模与需求分析、体系设计理念与体系设计、内场仿真实验与方案探索、体系原型研发与评估优化、外场集成试验与综合决策五个阶段,创新发展了体系设计、仿真试验、评估优化的理论方法、工具链路、集成环境,为无人集群的体系化、智能化、实战化提供了一定的理论与技术支撑。

金属空心球复合材料重力铸造工艺研究

基于对金属空心球复合材料的结构分析,采用金属型重力铸造法制备金属空心球复合材料。介绍了金属空心球复合材料金属型重力铸造工艺流程,并设计了一种成本低廉、简易成型、且能多次使用的金属型模具,且对金属空心球复合材料进行了实验试制及材料验证。结果表明,采用金属型重力铸造法能够制备出孔壁结构完整且孔洞随机分布的金属空心球复合材料,能实现空心球单一设计与梯度设计;金属空心球复合材料基体与空心球壁组织较为致密,且形成了厚度为25~30μm的界面层;金属空心球复合材料的应力-应变曲线具有明显的弹性阶段、塑性平台阶段和致密化阶段,且采用空心球梯度设计的金属空心球复合材料相较于空心球单一设计的金属空心球复合材料,其基本力学性能有明显的提升。最后,与传统的闭孔泡沫铝材料进行了对比分析,金属空心球复合材料整体稳定性更高,吸能效果更强。

基于改进连续时间动态系统的模拟SAT求解器

针对布尔可满足性问题的高效求解进行了研究。首先,通过对k-SAT问题和基于耦合常微分方程形式的确定性连续时间动态系统的分析,提出了一种基于时延信息形式的改进连续时间动态系统方程,以保持集中搜索特性;然后,提出了实现该系统方程的三个主要组件即信号动态电路、辅助变量电路和数字验证电路的模拟设计。在信号动态电路的设计中,设计了一种获得更高性能、更小面积和更低功耗的模拟硬件形式;在提出的辅助变量电路和数字验证电路的模拟硬件设计中,实现了避免梯度下降搜索陷入无解和确定给定问题的解是否已经找到的目标;同时提出了降低面积和功耗的可替代辅助变量电路的两种设计方案。仿真实验结果表明,提出的新的模拟SAT求解器不仅是有效的,而且相比于单一软件算法实现的SAT求解器和其他硬件类SAT求解器具有更高的加速性能和更低的功耗。

永磁同步直线电机的矢量控制

由于旋转电机加滚珠丝杠的传统机械结构加入了中间传动环节,无法进一步提升使用性能,研究了永磁同步直线电动机矢量控制算法.针对永磁同步直线电动机开展矢量控制算法分析以及验证工作,在矢量控制系统框架下进行了硬件搭建与软件设计,搭建了永磁同步直线电机矢量控制验证平台,测试核心算法,经过试验,设计的软/硬件能够对永磁同步直线电机进行有效控制,有较好的鲁棒性.

基于抽真空系统的继电器线圈BMC热固性塑料模具结构设计

对于原有BMC继电器线圈模具的外观较差、线圈断线丝、生产效率及合格率较低等问题,设计了一种1模16腔布局的上、下双顶出系统的压注模具,通过抽真空系统结构的设计将注塑压力从原充填压力19~42 MPa降低至22~25 MPa,成型件采用电加热及电阻测温方法,上模镶件的温度控制在148~151℃之间,下模镶件的温度控制在148~151℃之间,通过实际生产验证抽真空系统的效果。该改进方案使不合格品率从0.08%降低至0.015%,生产效率提高了20%。结果表明,该模具通过抽真空系统的应用提高了模具的可靠性及稳定性,满足自动化数字化生产线的要求,并且,提高了生产效率与产品的合格率。

基于Kriging模型与FORM的钢板组合梁桥结构优化设计

考虑材料参数的不确定性以及设计变量多重约束条件的影响,提出了基于可靠性分析的钢板组合梁桥结构优化设计方法。首先,利用拉丁超立方试验设计(Latin hypercube design,LHD)构建试验组合方案,并通过有限元分析获取试验设计组合下的最大挠度响应值。基于获取的训练样本,构建能够表征结构最大挠度值与随机输入之间映射关系的Kriging代理模型。基于建立的代理模型,以钢结构截面积最小化为目标函数,建立符合规范要求与可靠度约束的优化数学模型,并采用一阶可靠性方法(first order reliability method,FORM),实现设计变量优化。通过比较具有相同设计变量上限,但下限分别为初始值的80%和70%两种优化设计方案,评估了两者在相同阈值以及不同阈值下设计变量的优化结果。最后对方案二在阈值为17 mm下的优化结果进行极限状态验算。结果表明:两个优化设计方案在阈值为17 mm下的优化结果更具合理性,并且方案二在同一阈值下具有更高的优化程度。随着阈值增加,优化程度增加,且腹板高度在较大阈值下对结果影响更大,而翼缘宽度在较小阈值下影响更大。

特高压直流输电系统可控自恢复消能装置用慢速机械开关研制

慢速机械开关是特高压直流输电系统可控自恢复消能装置中重要的开关设备,在装置中起到控制和保护用,其必须具备短时间快速合闸、可靠开断避雷器残余直流持续电流的能力。介绍了慢速机械开关的方案设计、核心部件设计和校核以及型式试验,最终研制成功了慢速机械开关。

适用于用户认知挖掘的多维度用研方法探究

提高产品与交互设计项目中用户研究阶段,通过访谈获取用户认知与需求方法的有效性、广泛性及信息获取的深度。采用文献研究与项目实践相结合的探究方法,通过文献阅读,了解认知与需求挖掘方法,结合实际项目用户研究方法的思考、应用,进行总结归纳与整合。建立基于观察访谈法的用户认知与需求挖掘的方法框架,针对信息挖掘内容分散、广度低的问题,提出多维度信息获取方法;针对访谈层面的回答随机性与信息缺乏深度,提出用户探查和生活观察相结合的用户观察方法。研究建立了一套基于用户观察和情境访谈的多维度用户认知与需求的挖掘方法,为设计工作者在设计项目中开展用户认知和需求研究提供方法的参考,提高用户认知与需求挖掘的效率。

注水井生产封隔器液压坐封球座的研制

在油气田生产过程中,注水管柱的生产封隔器采用钢丝作业投捞堵塞器或常规球座辅助封隔器坐封,存在占用井口时间、作业步骤多且容易受井型井况限制等问题。为解决此类问题,设计一种注水井生产封隔器坐封球座,并详细介绍其工作原理。球座本体在井下受到拉伸、扭转、内压、外压等复杂井况,利用ANSYS Workbench模块模拟井下实际情况并对所设计结构进行强度分析,仿真结果表明液压式坐封球座结构在强度上满足使用要求。最后,通过试验验证,所设计的坐封球座可应用于注水井生产封隔器的坐封。

“巴遥一号”卫星双相机热设计及验证

针对“巴遥一号”卫星相机主体全寿命周期内温度应保持较高稳定性和均匀性的任务要求。通过建立热阻网络模型,分析热控设计的重点和难点,并提出有效管理热量传递和合理设计控温方式的方法;利用结构热控一体化设计解决双相机焦面电路高功率密度热量排散问题,采用直接与间接相结合的控温方式提高主光学结构温度稳定性。通过热仿真分析和热平衡试验验证热设计的准确性。相机入轨4年后1个月内的在轨温度变化显示,相机各部分温度水平和温度稳定性满足设计指标要求,镜头的温度波动范围在0.09~0.17℃,CCD的温度波动范围在0.93~4.30℃,表明相机热控设计合理有效。以上设计实践可为双相机一体化热控设计提供借鉴。

单边双针双线摆动缝合轨迹设计及实验验证

针对单边双针双线缝合头插刺机构无法缝制3 mm以上厚度预制体的问题,提出一种不对称的8字形运动轨迹并对插刺机构的运动轨迹进行了设计。首先,基于单边双针双线缝合工艺对插刺机构运动学进行分析,确定摆动插刺机构各构件的尺寸;其次,在ADAMS中构建机构模型并进行轨迹分析;最后,通过实验样机进行缝合实验。实验结果表明,设计的缝合机构可将实际缝合厚度不足3 mm提高到8 mm,并在缝合过程中形成稳定线环,验证了不对称8字形缝合工艺及摆动插刺机构的可靠性。

基于降低干耗的果蔬保鲜库风机选型方法

在果蔬保鲜库的建设与运行中,合理的冷风机选型对于保持产品质量和降低能耗具有关键意义。本文分析研究了影响冷风机选型的关键设计输入参数和相关条件,并探讨了输出参数确定与技术要求校核的方法。本研究的目标是果蔬保鲜库的冷风机选型提供可行实用的流程,以减少食品干耗,确保冷库内物品保鲜效果。通过设计参数的梳理、条件确认和校核,确定了风机选型方法。结果表明,本选型方法能有效减少食品干耗并提升能效。