Advances in Compact Manufacturing for Shape and Performance Controllability of Large-scale Components-A Review

Research on compact manufacturing technology for shape and performance controllability of metallic components can reanze the simplification and high-reliability of manufacturing process on the premise of satisfying the requirement of macro/micro-structure. It is not only the key paths in improving performance, saving material and energy, and green manufacturing of components used in major equipments, but also the challenging subjects in frontiers of advanced plastic forming. To provide a novel horizon for the manufacturing in the critical components is significant. Focused on the high-performance large-scale components such as bearing rings, flanges, railway wheels, thick-walled pipes, etc, the conventional processes and their developing situations are summarized. The existing problems including multi-pass heating, wasting material and energy, high cost and high-emission are discussed, and the present study unable to meet the manufacturing in high-quality components is also pointed out. Thus, the new techniques related to casting-rolling compound precise forming of rings, compact manufacturing for duplex-metal composite rings, compact manufacturing for railway wheels, and casting-extruding continuous forming of thick-walled pipes are introduced in detail, respectively. The corresponding research contents, such as casting ring blank, hot ring rolling, near solid-state pressure forming, hot extruding, are elaborated. Some findings in through-thickness microstructure evolution and mechanical properties are also presented. The components produced by the new techniques are mainly characterized by fine and homogeneous grains. Moreover, the possible directions for fin＇ther development of those techniques are suggested. Finally, the key scientific problems are first proposed. All of these results and conclusions have reference value and guiding significance for the integrated control of shape and performance in advanced compact manufacturing.

Leader trajectory planning method considering constraints of formation controller

To ensure safe flight of multiple fixed-wing unmanned aerial vehicles(UAVs)formation,considering trajectory planning and formation control together,a leader trajectory planning method based on the sparse A*algorithm is introduced.Firstly,a formation controller based on prescribed performance theory is designed to control the transient and steady formation configuration,as well as the formation forming time,which not only can form the designated formation configuration but also can guarantee collision avoidance and terrain avoidance theoretically.Next,considering the constraints caused by formation controller on trajectory planning such as the safe distance,turn angle and step length,as well as the constraint of formation shape,a leader trajectory planning method based on sparse A^(*)algorithm is proposed.Simulation results show that the UAV formation can arrive at the destination safely with a short trajectory no matter keeping the formation or encountering formation transformation.

Monitoring and Measuring Event Decision-Making Process Using Key Performance Indicators： Evidence From Italian Cruise Terminals

This paper investigates the control systems and coordination mechanisms applied in the relationships between cruise line companies and terminal concessionaires in the cruise events management when the ships are stopping on the quay. Using a case study methodology and focusing on the Italian context, this exploratory study, through a qualitative approach, interviewed two main cruise terminal concessionaires and indirectly observed events planned by cruise companies in sea ports selected for outlining the role of control systems, coordination, and knowledge sharing between the players in cruise events decision-making processes. The first results show that the cruise event management processes on ship berthing and on terminal are separated. The cruise companies don＇t involve terminal concessionaires in the event organization considering them only service suppliers Also, the concessionaires conceive the events planned in the cruise infrastructures as a business unit to optimize the space use, without any forms of coordination or control with cruise companies. Knowledge sharing, coordination, and control among the two players could support the planning, and management of ＂new cruise events＂ in which the visitors may be led from the infrastructure to the ships stopped on the quay. This study offers a set of key performance indicators to support the management, control, and coordination of each inter-organizational relationship identified. Managerial implications and suggestions for improving cruise events management have been provided.

Collaborative manufacturing technologies of structure shape and surface integrity for complex thin-walled components of aero-engine:Status,challenge and tendency

Presently,the service performance of new-generation high-tech equipment is directly affected by the manufacturing quality of complex thin-walled components.A high-efficiency and quality manufacturing of these complex thin-walled components creates a bottleneck that needs to be solved urgently in machinery manufacturing.To address this problem,the collaborative manufacturing of structure shape and surface integrity has emerged as a new process that can shorten processing cycles,improve machining qualities,and reduce costs.This paper summarises the research status on the material removal mechanism,precision control of structure shape,machined surface integrity control and intelligent process control technology of complex thin-walled components.Numerous solutions and technical approaches are then put forward to solve the critical problems in the high-performance manufacturing of complex thin-wall components.The development status,challenge and tendency of collaborative manufacturing technologies in the high-efficiency and quality manufacturing of complex thin-wall components is also discussed.

Collaborative force and shape control for large composite fuselage panels assembly

This study proposed a force and shape collaborative control method that combined method of influence coefficients(MIC)and the elitist nondominated sorting genetic algorithm(NSGA-II)to reduce the shape deviation caused by manufacturing errors,gravity deformation,and fixturing errors and improve the shape accuracy of the assembled large composite fuselage panel.This study used a multi-point flexible assembly system driven by hexapod parallel robots.The proposed method simultaneously considers the shape deviation and assembly load of the panel.First,a multi-point flexible assembly system driven by hexapod parallel robots was introduced,with the relevant variables defined in the control process.In addition,the corresponding mathematical model was constructed.Subsequently,MIC was used to establish the prediction models between the displacements of actuators and displacements of panel shape control points,deformation loads applied by the actuators.Following the modeling,the shape deviation of the panel and the assembly load were used as the optimization objectives,and the displacements of actuators were optimized using NSGA-II.Finally,a typical composite fuselage panel case study was considered to demonstrate the effectiveness of the proposed method.

基础隔震-外挂墙板减震钢筋混凝土框架振动台试验研究

该文提出一种新型的基础隔震-外挂墙板减震混合控制结构(简称“隔震-减震结构”)。该结构采用铅芯橡胶隔震支座作为基础隔震装置,上部结构则采用外挂墙板与U型金属消能器联合构成减震系统。通过减震与隔震混合控制,实现主体结构和围护墙体在罕遇地震下不发生损伤,可用于对韧性性能要求较高的生命线工程中。为对比研究隔震-减震结构与传统隔震结构的抗震性能,设计制作了一个在两方向上完全一致的1/2缩尺基础隔震钢筋混凝土框架结构,并在Y方向附加外挂墙板和U型金属消能器,形成隔震-减震结构,X方向不含外挂墙板,为隔震结构。分别在两个方向输入单向地震动进行振动台试验,试验结果表明:相比隔震结构,隔震-减震结构能进一步降低结构在设防和罕遇地震下的位移响应;隔震-减震结构在罕遇地震下最大层间位移角小于或接近钢筋混凝土框架结构弹性层间位移角限值,主体结构保持弹性,外挂墙板未出现损伤,可以实现预期的性能目标。

预应变SMA⁃TMD对钢框架结构抗震性能影响研究

针对钢结构在地震激励下加速度响应过大的问题,介绍了一种将形状记忆合金(SMA)应用到调谐质量阻尼器(TMD)装置中的解决方案,利用SMA的特性实现有效的自复位和稳定的阻尼,将预应变SMA棒应用到TMD中,提高装置的阻尼性能。通过试验测试及有限元模拟,研究安装施加预应变SMA-TMD的钢框架抗震性能。结果表明:预应变SMA棒不仅有助于自复位,而且还能大大提高SMA-TMD的等效黏滞阻尼比;经过优化的SMA-TMD装置可以大大降低钢框架的地震动响应,并加快地震能量消耗。

售货机升降系统S型速度控制策略

在传统三闭环控制方式下,售货机升降接货系统易因启停过程中加速度突变产生冲击,导致系统运行不平稳。针对这一问题,文中对传统升降系统加减速控制策略进行改进,加入前馈和微分负反馈,提出一种S型速度曲线控制算法。根据路径规划判别条件将S型速度曲线分为七段式、六段式和四段式3种,并给出各路径约束条件下的参数求解方法和具体执行流程。将该算法运用到升降控制系统中进行仿真和实际工况测试,实验结果表明,与传统三闭环控制相比,文中所提控制策略可以提高售货机升降系统运行的平稳性,减小冲击,使速度曲线更加柔和,并能够保持较好的跟踪性能。

适用于数字化主控室的核电厂HRA基础数据架构研究

目前国内开展核电厂人员可靠性分析(HRA)采用的人员失误概率基础数据库年限较为久远,且缺乏对于数字化主控室环境下人员失误模式的考虑。本文基于多个HRA方法及国外典型人员可靠性数据库的设计,结合国内电厂的实际情况,搭建了核电厂HRA基础数据库的框架,对于其中的绩效影响因子(PSF)架构采用数据库概念设计阶段的自顶向下设计方法,结合数字化环境下新增的人员失误模式,给出可供采集的PSF数据项,完成可适用于数字化环境的核电厂HRA基础数据库中PSF架构的搭建,并针对核电厂HRA基础数据架构着手开发相应的数据库软件,为核电厂人员可靠性数据的采集、防人因失误工作的开展提供有效支持。

电弧增材制造铝合金的“控形”和“控性”技术研究现状

电弧增材制造铝合金具有沉积速度快、设备成本低、材料利用率高等优点,受到工业界和学术界的极大关注。但电弧增材制造固有的熔化和凝固特性决定最终材料存在“控形”“控性”的难题。本文从“控形”“控性”两方面对电弧增材制造铝合金的国内外进展进行分析,重点阐述了工艺参数优化、在线处理方式如基板预热、冷轧、熔池在线监测、微铸锻、搅拌摩擦焊等,以及后处理方式,讨论了不同技术的发展现状及趋势,并提出电弧增材制造铝合金“控形”“控性”的发展方向。

玫瑰花状MoS_(2)对丁基黄原酸钾的吸附-光催化协同去除性能研究

利用水热法合成玫瑰花状MoS_(2),研究其对丁基黄原酸钾的吸附-光催化协同去除性能。结果表明,成功制备了具有光催化性能与吸附性能的玫瑰花状MoS_(2);在pH=7、MoS_(2)用量为25 mg、吸附时间为30 min条件下,MoS_(2)对丁基黄原酸钾的最大吸附容量达110.93 mg·g^(-1);在300 W氙灯下照射30 min时,MoS_(2)对丁基黄原酸钾的降解效率为81.99%;而通过光催化降解-吸附的协同作用,在40 min时丁基黄原酸钾去除率达99.89%;经过5次循环后,MoS_(2)对丁基黄原酸钾的协同去除率仍大于95%。此研究为MoS_(2)在含黄药废水处理方面开辟一种新方法。

基于网源协同量化提升“两个细则”调频性能研究与应用

并网机组的调频性能是保证电力系统稳定运行和电力供应质量的重要指标之一。山东电网由于外电入鲁和新能源装机比重不断增加,整个能源结构发生了重大改变,调频性能的提升变得尤为重要。目前,发电机组存在调频性能波动较大、调频响应速度较慢、调节精度差等问题,对电网的稳定性和可靠性产生了一定的影响。为此,通过基于网源协同方式的量化分析方法和综合研究影响“两个细则”调频性能的各种因素,建立数学模型并进行实验,评估和优化调频性能,制定相应的调频控制策略和改进措施。这对于并网机组的稳定运行和电力供应质量的提高具有重要意义。

汽车下控制臂性能优化及轻量化设计

汽车下控制臂需要具备一定的强度和刚度以抵抗挤压、冲击变形,还需要具备较高的固有频率,以避免低频共振,产生噪音。文章以某在研汽车下控制臂为轻量化设计对象,通过仿真分析识别出屈曲力不足的设计风险,综合运用形状、拓扑优化方法重新设计了控制臂,并对新设计进行性能仿真。结果表明,新控制臂消除了屈曲力不足的设计风险,新设计较原设计减重6.6%。文章采用线性优化方法解决高度非线性的屈曲力优化问题,采用拓扑优化识别出载荷的传递路径,为汽车控制臂的屈曲力优化及轻量化设计提供新思路。

煤矿巷道智能掘进机器人系统关键技术研究

按照国家“加快煤矿智能化发展”的战略部署,贯彻“采掘并重,掘进先行”方针,针对煤矿巷道掘进存在地质条件复杂、工艺装备落后、作业人员偏多、操作环境恶劣、安全风险严竣、采快掘慢失衡等问题,深入总结分析国内外煤矿巷道智能掘进技术的研究动态,指出存在的不足和亟待解决的问题。针对煤矿复杂地质条件下的巷道掘进难题,研发了一种全新的集截割、临时支护、钻锚和锚网运输等并行智能协同的煤矿巷道掘进机器人系统。通过研究进展分析、理论方法探索以及研发实践,提出构建煤矿巷道智能掘进机器人系统的3大关键技术问题及其研究内涵,创建解决关键技术问题的研究体系架构:煤矿巷道掘进机器人系统建模与围岩耦合机理;煤矿巷道掘进机器人系统智能协同控制技术,提出数字孪生驱动的虚拟现实远程智能控制方法;煤矿巷道快速掘进机器人系统精确定位定向和定形技术,提出机器人系统全局和局部精准定位定向及断面截割精准定形控制方法。破解复杂地质条件下的煤矿巷道智能掘进机器人系统关键技术难题,对于研发高质量、高可靠、高效率、高智能的煤矿巷道智能掘进机器人系统,从根本上改善掘进工作面环境,解放生产力,全面提高煤矿巷道掘进效率和质量。

差动式磁控形状记忆合金执行器研究

磁控形状记忆合金(MSMA)是一种新型具有形状记忆功能的合金材料,特别适合于制造高精度的运动与位置控制执行器。针对传统MSMA执行器磁场励磁控制功率大、恢复弹簧压力不易调整和MSMA变形受温度影响较大等缺点,提出了一种差动式MSMA执行器,采用永磁体产生恒定偏磁磁场,励磁绕组仅提供差动可控磁场,两个MSMA元件轮流工作,其中一个元件变形产生的压力用于另一个元件恢复变形从而取消了恢复弹簧。该差动式MSMA执行器减小了控制功率,消除了温度对MSMA的影响,提高了控制精度、稳定性和动态响应速度。文中给出了样机实验结果。

SMA复合摩擦阻尼器性能的试验研究

利用形状记忆合金(SMA)的超弹性效应及高阻尼性能,结合传统Pall摩擦型阻尼器的特点,提出了一种SMA复合摩擦阻尼器。在建立阻尼器力学分析模型的基础上,对SMA复合摩擦阻尼器的性能进行了试验研究,分析了位移幅值、加载频率等对阻尼器的等效刚度、单位循环耗能和等效阻尼比的影响,并与理论分析结果进行了对比。研究表明,SMA复合摩擦阻尼器在加卸载循环下会形成比较稳定的滞回曲线,表明这种阻尼器具有良好的耗能能力。

IT外包项目中控制机制与合作绩效的实证研究——基于IT服务提供商的视角

有效的控制机制对IT外包项目的关系治理与成功实施具有重要意义。同时考虑基于契约的正式控制和基于信任的非正式控制对外包合作绩效的影响,并以本土的IT外包服务提供商企业为对象进行了实证分析,通过325份问卷的调研数据,探讨了契约控制与信任控制在项目获取途径的调节作用下,通过感知不确定的中介作用对外包合作绩效的影响。结果表明:信任控制与外包合作绩效呈正相关关系,并且通过感知不确定性的完全中介作用对外包合作绩效产生正向影响;而契约控制与外包合作绩效的相关关系未得到实证支持;项目获取途径对控制机制与外包合作绩效间关系的调节效应不显著。

非线性锅炉汽轮机系统的鲁棒控制(英文)

本文采用环路成形Ｈ∞控制方法对一非线性锅炉汽轮机系统进行设计．为了能方便地在实际工程中实现复杂的控制器，本文提出用多变量ＰＩＤ 控制器逼近所得控制器的方法．最终简化的控制器由位于主对角通道的三个ＰＩ控制器及位于次对角通道的一个ＰＩ控制器实现，仿真表明所得控制器具有较好的信号跟踪、抗干扰性能，并能在较大范围操作点工作。

“凝心”能“协力”吗?——母公司文化控制、研发协同与子公司创新绩效关系研究

企业集团内部协同创新问题受到广泛关注,但对其前置因素的探索仍有未尽之处。本文从母公司控制方式入手,考察母公司文化控制、母子公司和子子公司研发协同对子公司创新绩效的影响。研究发现:(1)母公司文化控制促进了包括母子公司、子子公司研发协同在内的公司间研发协同;(2)研发协同提升了子公司创新绩效;(3)研发协同在母公司文化控制与子公司创新绩效间起中介作用;(4)母公司文化控制通过研发协同对子公司创新绩效产生的促进作用随着外部环境不确定性的提高而增强。上述结论揭示了母公司文化控制在研发管理中的卓越作用,为集团"软控制"效果提供了证据支持。

产学研合作与创新绩效关系的META分析

在文献整理与归纳的基础上,提出产学研合作与创新绩效之间关系的假设模型。通过国内外主要文献数据库的查找,以及离群值和偏倚性检验,最终获得39篇相互独立的样本文献。经Meta分析方法处理后,研究得到了以下结论,产学研合作对创新绩效存在显著的正向关联;产学研合作对创新绩效的影响随时间因素和文化差异的变化而变化;当产学研合作为多维结构以及研究模型为结构模型时,产学研合作对创新绩效的作用更显著;中介变量的存在情况未能显著调节两者之间的相关关系。