Virtually coupled train set control subject to space-time separation:A distributed economic MPC approach with emergency braking configuration

The emerging virtual coupling technology aims to operate multiple train units in a Virtually Coupled Train Set(VCTS)at a minimal but safe distance.To guarantee collision avoidance,the safety distance should be calculated using the state-of-the-art space-time separation principle that separates the Emergency Braking(EB)trajectories of two successive units during the whole EB process.In this case,the minimal safety distance is usually numerically calculated without an analytic formulation.Thus,the constrained VCTS control problem is hard to address with space-time separation,which is still a gap in the existing literature.To solve this problem,we propose a Distributed Economic Model Predictive Control(DEMPC)approach with computation efficiency and theoretical guarantee.Specifically,to alleviate the computation burden,we transform implicit safety constraints into explicitly linear ones,such that the optimal control problem in DEMPC is a quadratic programming problem that can be solved efficiently.For theoretical analysis,sufficient conditions are derived to guarantee the recursive feasibility and stability of DEMPC,employing compatibility constraints,tube techniques and terminal ingredient tuning.Moreover,we extend our approach with globally optimal and distributed online EB configuration methods to shorten the minimal distance among VCTS.Finally,experimental results demonstrate the performance and advantages of the proposed approaches.

Lattice configurations in spin-1 Bose–Einstein condensates with the SU(3) spin–orbit coupling

We consider the SU(3) spin–orbit coupled spin-1 Bose–Einstein condensates in a two-dimensional harmonic trap. The competition between the SU(3) spin–orbit coupling and the spin-exchange interaction results in a rich variety of lattice configurations. The ground-state phase diagram spanned by the isotropic SU(3) spin–orbit coupling and the spin–spin interaction is presented. Five ground-state phases can be identified on the phase diagram, including the plane wave phase, the stripe phase, the kagome lattice phase, the stripe-honeycomb lattice phase, and the honeycomb hexagonal lattice phase. The system undergoes a sequence of phase transitions from the rectangular lattice phase to the honeycomb hexagonal lattice phase, and to the triangular lattice phase in spin-1 Bose–Einstein condensates with anisotrpic SU(3) spin–orbit coupling.

Three Dimensional Coupling between Elastic and Thermal Fields in the Static Analysis of Multilayered Composite Shells

This new work aims to develop a full coupled thermomechanical method including both the temperature profile and displacements as primary unknowns of the model.This generic full coupled 3D exact shell model permits the thermal stress investigation of laminated isotropic,composite and sandwich structures.Cylindrical and spherical panels,cylinders and plates are analyzed in orthogonal mixed curved reference coordinates.The 3D equilibrium relations and the 3D Fourier heat conduction equation for spherical shells are coupled and they trivially can be simplified in those for plates and cylindrical panels.The exponential matrix methodology is used to find the solutions of a full coupled model based on coupled differential relations with respect to the thickness coordinate.The analytical solution is based on theories of simply supported edges and harmonic relations for displacement components and sovra-temperature.The sovra-temperature magnitudes are directly applied at the outer faces through static state hypotheses.As a consequence,the sovra-temperature description is assumed to be an unknown variable of themodel and it is calculated in the sameway as the three displacements.The final systemis based on a set of coupled homogeneous differential relations of second order in the thickness coordinate.This system is reduced in a first order differential relation system by redoubling the number of unknowns.Therefore,the exponential matrix methodology is applied to calculate the solution.The temperature field effects are evaluated in the static investigation of shells and plates in terms of displacement and stress components.After an appropriate preliminary validation,new benchmarks are discussed for several thickness ratios,geometrical data,lamination sequences,materials and sovra-temperature values imposed at the outer faces.Results make evident the accordance between the uncoupled thermo-mechanical model and this new full coupled thermo-mechanical model without the need to separately solve the Fourier heat conduction relation.Both effects connected with the thickness layer and the related embedded materials are included in the conducted thermal stress analysis.

Strong coupling in silver-molecular J-aggregates-silver structure sandwiched between two dielectric media

We theoretically investigate the strong coupling in silver-molecular J-aggregates-silver structure sandwiched between two dielectric media by using classical methods. Fresnel equations are employed to solve our proposed structure. The results show that both the reflection and transmission spectra show a Rabi splitting-like line shape, revealing the strong coupling phenomenon. Furthermore, the radiative angle versus incident wavelength exhibits a Fano line shape. The strong coupling phenomenon can be well tuned by controlling the surface plasmon excitation, such as the incident angle and the thickness of the silver films. Our structure has potential applications in quantum networks, optical switches, and so on.

High-Sensitivity Tunnel Magnetoresistance Sensors Based on Double Indirect and Direct Exchange Coupling Effect

Detection of ultralow magnetic field requires magnetic sensors with high sensitivity and low noise level,especially for low operating frequency applications.We investigated the transport properties of tunnel magnetoresistance(TMR)sensors based on the double indirect exchange coupling effect.The TMR ratio of about 150%was obtained in the magnetic tunnel junctions and linear response to an in-plane magnetic field was successfully achieved.A high sensitivity of 1.85%/Oe was achieved due to a designed soft pinned sensing layer of CoFeB/NiFe/Ru/IrMn.Furthermore,the voltage output sensitivity and the noise level of 10.7 mV/V/Oe,10 nT/Hz^(1/2)at 1 Hz and3.3 nT/Hz^(1/2)at 10 Hz were achieved in Full Wheatstone Bridge configuration.This kind of magnetic sensors can be used in the field of smart grid for current detection and sensing.

The Use of a Combination of RDC and Chiroptical Spectroscopy for Determination of the Absolute Configuration of Fusariumin A from the Fungus Fusarium sp.

A new alkylpyrrole derivative,fusariumin A(1),was isolated from the culture broth of the fungus Fusarium sp.The absolute configuration of fuasiumin A has been established as(2'R,3'R)using a combination of RDC(residual dipolar coupling)-based NMR and DFT-supported chiroptical spectroscopy.It is worth to note that in this study without the aid of the RDC analysis,an unambiguous determination of configuration and conformation was not feasible due to the excessive conformational possibilities of this open-chain compound.

双流耦合构型混合动力拖拉机旋耕工况控制策略研究

大功率拖拉机作业时载荷冲击会造成发动机的输出转矩大范围波动,为减小载荷冲击对拖拉机动力单元的影响,提出以发动机和双电机为动力源的拖拉机双流耦合动力系统构型,以减小载荷冲击引起的动力传动系统换挡频次。基于Haar小波分解提出了基于功率预测的转矩分配策略,首先记录拖拉机的作业参数,基于径向基神经网络对拖拉机旋耕作业时的功率需求进行预测,由Haar小波变换确定高频和低频转矩需求值的范围,并分别由电机和发动机提供。最后,通过硬件在环试验对提出的动态转矩分配进行了可行性验证,测试结果表明:提出的基于神经网络功率需求预测模型对行驶端和动力输出端(Power take-off,PTO)的功率进行预测,实际值和预测值均方根误差分别占最大功率的7.6%和7.9%;提出的转矩分配策略能够应对拖拉机旋耕时的载荷波动。发动机转矩波动与传统构型相比减小35.0%,有效地缩小了发动机转矩波动范围,缓解了拖拉机作业时载荷冲击对发动机的影响。

筒式永磁联轴器传动特性解析算法及结构优化

永磁联轴器存在结构复杂、装配困难、抗偏载能力差等问题,传动性能评估中,有限元仿真计算时间长,解析计算准确性低。为此,设计了新型筒式永磁联轴器构型,梯形磁体与楔形插槽可实现永磁体自吸装配。针对该构型,提出了一种等效磁荷磁路解析计算方法计算传递转矩,并设计了一种吸斥复合永磁联轴器构型。对两种永磁联轴器在内外转子相对偏转0°~45°时的传递转矩、径向相对偏移-3.8~3.8 mm的受力情况进行了仿真及实验验证。研究结果表明,提出的解析算法较仿真结果误差减小50%,且解析计算用时由2 h缩短为2 min。与筒式构型相比,吸斥复合构型的径向偏载最大受力减小48.59%。最后为永磁联轴器设计优化提出了合理化建议。

旋流冲击下不同孔型发散冷却壁面耦合传热特性对比

采用红外热成像技术考察了不同冷气压降下圆孔、扇形孔和扩张孔的发散冷却特性。结果表明:由于旋流冲击效应,壁面出现局部低冷效区域,且与孔型无关;孔型变化仅影响壁面的冷却效果,增大冷却空气压降可改善冷效效果,低冷效区域的面积也随之减小;冷却孔型和冷却空气压降的差异会导致最低冷效点位置发生迁移;随着冷气速度的增大,该点位置向上游方向迁移;就均匀性而言,冲击点圆孔的最低效率比面积平均值降低14.3~27.5百分点,扇形孔和扩张孔的最低冷效与平均水平差别更大,冷效均匀性更差;扩张孔的综合冷却效率最高,但均匀性最差。

基于Web组态低代码智能联轴器监测系统

泰尔重工现有的联轴器监测系统存在诸多问题,如内容单一、格式僵化、开发成本高等,无法满足用户对监控的定制化需求。基于Web数字组态低代码开发技术,在调研了联轴器设备现有和潜在需求的基础上,对联轴器相关的设备业务逻辑进行统一抽象和封装。从而开发了联轴器相关设备可复用的组件和低代码组件工具箱,并以此为基础为用户开发了可视化IDE,包括拖拽组件和简单Web页面表单配置参数的自定义操作平台,使智能联轴器监测系统的可视化,个性化的定制更加简便。实际使用表明,该平台可为联轴器监控系统提供快速开发平台,满足用户日常提出的自定义扩展开发需求。系统为未来升级提供了灵活性和可扩展性。

Bennett机构构型的环形可展天线桁架热致振动分析

卫星在运行过程中会频繁进出地球阴影区,天线桁架在太阳热辐射和无辐射的交替影响下,会产生热致振动响应,从而影响天线的使用精度和寿命。为提高天线的稳定性,以Bennett机构替代构型构建环形天线桁架,并建立有限元模型,计算其在突加热载荷条件下的瞬态温度场;通过热-结构间接耦合仿真,分析桁架在突加热载荷条件下的热致振动响应,并与传统的对角线伸缩式环形桁架进行比较。结果表明,相比于传统的对角线伸缩式环形桁架,Bennett替代构型环形桁架在热载荷作用下振幅明显减小,表现出良好的稳定性。

“光伏-储能”耦合参与调峰的配电网运行优化配置

本文主要研究了“光伏-储能”耦合参与调峰的配电网运行优化配置问题。随着光伏发电在配电网中的广泛应用,如何有效利用光伏发电并解决其随机性和间歇性问题成为了关键。通过引入储能系统,可以实现光伏发电与储能的优化配置,提高配电网的稳定性和经济性。首先分析了“光伏-储能”型配电网的供能关系,然后确定配电网耦合调峰作用的实施效果,最后调节相关电力储能设备,实现对“光伏-储能”配电网的运行优化。

嵌入后退式子母弹高速分离安全性评价方法

嵌入后退式子母弹分离过程中,当子弹的后、中吊挂脱离导轨后,子弹运动姿态受到母弹的牵连,处于半约束状态,吊挂与导轨间的接触碰撞和母弹对子弹的气动干扰对分离过程具有极大的影响。为了为嵌入后退式子母弹高速分离安全性设计提供重要的理论支撑依据,确保子母弹安全分离,提出了子母弹高速分离高精度时空数值仿真安全性评价方法。在构建子母弹分离过程变构型气动力响应面模型和变构型变质量多体动力学模型的基础上,建立了子母弹分离过程变构型变质量组合体多体-气动流固耦合高精度时空数值仿真平台。基于该模型对不同的初始边界条件的子母弹分离过程进行仿真计算,获得了子母弹分离过程中的姿态参数,可对子母弹分离安全性进行动态评估;确定了子母弹可安全分离初始边界条件,为制定有利于提高子母弹高速分离安全性的技术措施提供了量化设计依据。通过仿真算例和试验表明,所构建的子母弹高速分离高精度时空数值仿真平台具有较高的准确性和可信度,研究结果对嵌入后退式子母弹高速分离安全性评价具有非常重要的工程价值。

新型城镇化与物流产业耦合协调发展路径研究

基于TOE框架,将耦合协调模型与fsQCA相结合,选取科研投入、设施建设、产业结构、产业聚集、对外开放程度、居民消费水平六个指标为前因变量,以耦合协调度作为结果变量,对全国31个省份展开研究,探究多要素驱动新型城镇化与物流产业协调发展的路径。研究结果表明,目前我国新型城镇化与物流产业耦合协调度总体偏低且存在明显的区域差异;新型城镇化与物流产业耦合协调发展是由多种因素共同驱动的,高耦合协调路径可归纳为均衡型(科研型)、均衡型(设施型)、技术-产业型、技术-环境型(开放型)、技术-环境型(消费型)等五种类型。

多要素驱动区域创新链耦合协调度提升的路径研究——TOE框架下的fsQCA分析

有效提升区域创新链耦合协调度是实施创新驱动发展战略过程中亟待解决的现实问题。基于“知识创新—研发创新—产品创新”区域创新链,在“技术—组织—环境”(TOE)理论框架下,运用模糊集定性比较分析(fsQCA)方法,对中国内地31个省份开展评价,探究多要素驱动区域创新链耦合协调度提升的条件组态和路径。研究结果表明,东、中、西部各省份存在显著差异,且有效提升区域创新链耦合协调度的关键要素有2个,即数字化技术水平、市场化水平;提升路径为4条,即知识—研发—产品创新均衡型、研发—产品创新引领型、知识—研发创新引领型、产品创新引领型。上述结论有助于拓展区域创新链研究视角,同时,对提升不同地区区域创新链耦合协调度具有现实价值。

飞机轮组滑水行为与道面积水附加阻力

针对飞机在不同滑行状态与道面积水条件下的轮组滑水行为特征差异问题,开展道面积水附加阻力研究,改进基于道面对轮胎竖向支撑力指标的临界滑水状态判定条件。以空客A320机型主起落架为研究对象,建立双轮轮组-积水道面流固耦合滑水分析模型,对道面积水附加阻力影响因素进行规律分析。结果表明:积水附加阻力在轮胎临界滑水状态达到最大,所得临界滑水速度与NASA公式计算结果相差小于5%,且在滑水过后持续影响滑行状态,较道面支撑力更适合作为滑水分析指标;飞机着陆时轮胎高速接地可发生瞬时滑水,同等参数条件下道面积水阻力始终低于起飞过程,着陆阶段临界滑水速度较起飞阶段低8.3%~10.6%,着陆阶段飞机滑水风险更高,符合事故统计规律;轮辙变形改变道面积水条件并引起轮组内部滑水过程时空差异;仅对平整道面理想积水情况,道面积水阻力轮组系数可近似按轮胎数量计算,有轮辙道面条件下双轮轮组系数中位数低于2.0,造成着陆减速滑行过程延长。

考虑源荷不确定性的氢能微网容量优化配置

针对电热气耦合微网存在的能源利用率低、鲁棒性难以控制的问题,提出考虑源荷不确定性的氢能微网容量优化配置方法。首先,利用氢储能、电锅炉和有机朗肯循环(organic Rankine cycle,ORC)系统增加传统微网的电热气转换途径,构建多能耦合、低碳高效的氢能微网;然后,提出一种基于有序聚类算法和模糊C均值(fuzzy C-means,FCM)聚类算法的电负荷-风电出力典型日选取方法,以年化总成本最小为优化目标,计及功率平衡、设备运行、储氢系统和天然气管道等约束,建立氢能微网容量优化配置模型;最后,对某工业园区的实际数据进行分析,得到系统中各设备的优化配置方案以及成本大小,并进行灵敏度分析,验证了所提模型可有效降低系统总成本、减少碳排放。

考虑动力电池梯次利用的充电站容量优化配置

为提高电动汽车充电站储能系统稳定性、安全性和经济性,提出一种考虑动力电池梯次利用的充电站光储容量优化配置方法。首先,针对退役动力电池考虑了电池充放电深度和循环次数对使用寿命的影响,建立了退役动力电池容量衰减和寿命损耗模型,基于容量衰减和寿命损耗模型建立退役动力电池荷电状态(state of charge,SOC)与健康状态(state of health,SOH)耦合关系评价模型;其次,在SOC与SOH耦合关系评价模型的基础上,以充电站年净收益最优为目标函数建立充电站容量优化配置模型;最后,在满足一定能量交换策略的前提下,以某地区光伏储能电站为例对模型进行求解。通过算例分析得出:基于退役电池SOC与SOH耦合关系评价模型进行梯次利用的储能容量优化配置能使整个储能系统的功率峰值降低,且相较于无评价模型系统的功率更加平滑,有利于延长储能系统的寿命周期,提高了系统的稳定性和经济性。

破解中国能源“不可能三角”——基于省域面板数据的动态QCA分析

使用2005—2021年省域面板数据,对我国能源“安全—经济—绿色”的耦合协调发展状况进行评估,并采用动态QCA方法探索时间纵轴上“技术—组织—环境”因素对能源“安全—经济—绿色”耦合协调发展的组态效应。研究表明,我国的确存在一定的能源“不可能三角”问题,且任何单一因素都不能驱动能源“安全—经济—绿色”耦合协调发展,需要多因素的协同驱动。此外,存在三种可推动能源“安全—经济—绿色”耦合协调发展的组态模型,分别为“技术—组织—环境协同驱动”模型、“组织—环境驱动”模型和“技术—环境驱动”模型。

面对称无尾高超声速飞行器三通道耦合失稳判据

针对新一代面对称高超声速飞行器通常采用的无尾布局、小控制面设计而导致的飞行器稳定性大幅降低以及通道间控制耦合严重的问题,基于飞行器的六自由度动力学方程,利用线化小扰动理论,通过推导引入了飞行器三通道开环和闭环的气动稳定性耦合判据,其判据中包括了传统的气动静导数和动导数,组成了新的三通道耦合稳定性判据体系。相比现有判据,本研究新引入了俯仰和滚转通道静稳定性耦合判据,以及三通道的动稳定性耦合判据,并用数值仿真验证了本文引入的判据在判断无尾布局高超声速飞行器稳定特性中的有效性,为该类飞行器提供了快速有效的稳定性分析工具。