Research on the Coordinated Control of the Multi-point Array Support Force of Complex Structural Parts

Multi-point array flexible tooling based on multilateration is widely used in the processing and manufacturing of complex curved surface parts. However, during the positioning of workpieces, the force exerted on each flexible support point is not uniform, and there exists force coupling between the support units. In response to the force coupling problem in the multi-point array positioning support process, a coordinated control method for the support force of multi-point array positioning combining correlation coefficient and regression analysis was proposed in this paper. The Spearman correlation coefficient was adopted in this method to study the force coupling correlation between positioning points, and a mathematical model of force coupling was established between positioning units through regression analysis, which can quickly and accurately perform coordinated control of the multilateration support system, and effectively improve the force interference of the multi-point array positioning support scene.

Application of a compound controller based on fuzzy control and support vector machine to ship's boiler-turbine coordinated control system

Multivariables, strong coupling, nonlinearity, and large delays characterize the boiler-turbine coordinated control systems for ship power equipment. To better deal with these conditions, a compound control strategy based on a support vector machine （SVM） with inverse identification was proposed and applied to research simulating coordinated control systems. This method combines SVM inverse control and fuzzy control, taking advantage of the merits of SVM inverse controls which can be designed easily and have high reliability, and those of fuzzy controls, which respond rapidly and have good anti-jamming capability and robustness. It ensures the controller can be controlled with near instantaneous adjustments to maintain a steady state, even if the SVM is not trained well. The simulation results show that the control quality of this fuzzy-SVM compound control algorithm is high, with good performance in dynamic response speed, static stability, restraint of overshoot, and robustness.

Coordination environment of active sites and their effect on catalytic performance of heterogeneous catalysts

The structural complexity of supported metal catalysts,playing significant role in a wide range of chemical technologies,have prevented us from deeply understanding their catalytic mechanisms at atomic level.A fundamental understanding of the nature of active sites and structure–performance relationship of supported metal catalysts from a comprehensive view will open up numerous new opportunities for the development of advanced catalysts to address the global challenges in energy conversion and environmental protection.This review surveys the effects of multiple factors,including the metal size,shape,support,alloy and ligand modifier,on the coordinated environment of active center and further their influence on the catalytic reactions,aiming to provide guidance for the design of industrialized heterogeneous catalysts with extraordinary performance.Subsequently,the key structure characterization techniques in determining the coordination structure of active metal sites,especially the dynamic coordination structure change under the reaction condition,are well summarized.A brief summary is finally provided together with personal perspectives on the further development in the field of heterogeneous metal catalysts.

Coordinated control strategy for robotic-assisted gait training with partial body weight support

Walking is the most basic and essential part of the activities of daily living. To enable the elderly and non-ambulatory gait-impaired patients, the repetitive practice of this task, a novel gait training robot(GTR) was designed followed the end-effector principle, and an active partial body weight support(PBWS) system was introduced to facilitate successful gait training. For successful establishment of a walking gait on the GTR with PBWS, the motion laws of the GTR were planned to enable the phase distribution relationships of the cycle step, and the center of gravity(COG) trajectory of the human body during gait training on the GTR was measured. A coordinated control strategy was proposed based on the impedance control principle. A robotic prototype was developed as a platform for evaluating the design concepts and control strategies. Preliminary gait training with a healthy subject was implemented by the robotic-assisted gait training system and the experimental results are encouraging.

Temperature Prediction Model Identification Using Cyclic Coordinate Descent Based Linear Support Vector Regression

Temperature prediction plays an important role in ring die granulator control,which can influence the quantity and quality of production. Temperature prediction modeling is a complicated problem with its MIMO, nonlinear, and large time-delay characteristics. Support vector machine( SVM) has been successfully based on small data. But its accuracy is not high,in contrast,if the number of data and dimension of feature increase,the training time of model will increase dramatically. In this paper,a linear SVM was applied combing with cyclic coordinate descent( CCD) to solving big data regression. It was mathematically strictly proved and validated by simulation. Meanwhile,real data were conducted to prove the linear SVM model's effect. Compared with other methods for big data in simulation, this algorithm has apparent advantage not only in fast modeling but also in high fitness.

构网型单元异常下的孤岛交直流混合微电网群分布式协同控制策略

当构网型单元处于限功率运行与故障等工况下,传统孤岛交直流混合微电网群分布式协同控制方法易造成交流子微网母线电压与频率失去支撑,进而导致系统失稳.为解决上述问题,本文提出了一种面向构网型单元限功率运行与故障工况的孤岛交直流混合微电网群分布式协同控制策略.当子微网构网型单元处于限功率运行或故障工况时,首先,在构网型单元异常子微网变换器控制层,构网型单元将输出功率钳位于最大值或退出运行,跟网型单元通过与互联变换器进行二次协同控制,实现功率的合理分配;其次,在网间互联变换器控制层,与构网型单元异常子微网相连的互联变换器转为构网型控制模式,为构网型单元异常子微网提供母线电压与频率支撑,其余互联变换器按照正常子微网自身剩余容量分担构网型单元异常子微网所需的支撑功率.多工况下的仿真结果表明,当负荷连续增加,构网型单元处于限功率运行工况时,所提分布式协同控制策略可通过网间互联变换器的变模式运行,实现构网型单元异常子微网交流母线电压与频率的快速恢复、跟网型单元输出功率的精准分配;当构网型单元处于故障工况时,所提分布式协同控制策略可以有效解决构网型单元异常子微网因交流母线电压与频率失去支撑导致的失稳问题.

ZigBee技术和支持向量机下室内火灾自动报警系统

室内火灾报警系统只能基于少量传感器的数据进行判断,容易受到烟雾、温度等干扰,导致误判率较高。为此,基于ZigBee技术和支持向量机设计一种室内火灾自动报警系统。采用传感器节点采集室内烟雾浓度与温度信息,通过ZigBee路由设备将采集的信息转发至ZigBee协调器内。利用基于负载均衡的ZigBee网络多径路由算法建立信息传输路径,将ZigBee路由设备转发的信息传输至支持向量机处理模块内。使用支持向量机算法处理烟雾浓度与温度信息,获取高校室内火灾类型的发生概率,并与事先设置的判别阈值进行比较,当火灾发生概率大于阈值,自动报警模块会自动发出警报。实验结果表明:所设计系统火灾信息采集精度较高,无线网络生存周期长,具备较优的信息传输效果,且能够有效计算高校室内火灾类型发生概率并自动发出警报。

含跟网/构网型混联多馈入系统协调优化配置方法

随着传统同步机组被电力电子设备逐步取代,电力系统由原来的“物理同步”逐渐转变为“控制同步”。因此,由变流器控制环节引发的稳定问题受到广泛关注。已有研究表明,含跟网/构网型设备的混联多馈入系统中构网型设备能够抑制弱电网下由跟网型设备并网引起的次同步振荡,然而其在强电网下容易导致系统出现低频振荡现象。而目前电力系统仍处于向“双高”系统转变的过渡阶段,关于不同电网强度下混联多馈入系统中跟网/构网型变流器对电网电压支撑能力的量化评估及其在多频段下的协调优化配置方法仍不清晰。为此,该文首先对单馈入跟网/构网型变流器并网系统进行模态分析,探究不同电网强度下跟网/构网型变流器对应的主导振荡模态在多频段下的分布特性,并形成混联多馈入系统的协调优化配置原则。其次,基于模态解耦的思想对混联多馈入系统的稳定性进行等效近似,揭示多频段下系统主导振荡模态阻尼比与跟网/构网型支撑能力量化指标之间的关系。由此,提出一种面向系统小干扰稳定性提升的跟网/构网型协调优化配置方法。最后,通过仿真算例验证所提混联多馈入系统等效近似方法的正确性和协调优化配置方法的有效性。

出院准备度的概念分析

运用经典概念分析法,对出院准备度的起源、定义、属性特征、案例演示、前因/后果及评估工具进行综合分析,为国内开展出院准备相关研究及实施出院准备服务提供参考,促进我国出院护理发展。

受限空间环境下的架桥机横移架梁施工技术研究

针对狭窄空间和特殊地形条件下架桥机的横向移传与放置桥梁节段所面临的技术挑战展开了深入探讨与分析,并通过对多个城市轨道交通项目进行采样分析,构建了模拟横移架梁过程的精确数值模型,确立了横移过程中的关键影响因子,同时,对于特异性地质与空间限制条件,创新性地提出了一套模块化横移支架系统,该系统具备快速组装融合与位置精确调整的优势,显著提升了在受限空间内的架梁工作效率和可行性。

New insight into the stability and dynamics of fluid-conveying supported pipes with small geometric imperfections

In several previous studies,it was reported that a supported pipe with small geometric imperfections would lose stability when the internal flow velocity became sufficiently high.Recently,however,it has become clear that this conclusion may be at best incomplete.A reevaluation of the problem is undertaken here by essentially considering the flow-induced static deformation of a pipe.With the aid of the absolute nodal coordinate formulation(ANCF)and the extended Lagrange equations for dynamical systems containing non-material volumes,the nonlinear governing equations of a pipe with three different geometric imperfections are introduced and formulated.Based on extensive numerical calculations,the static equilibrium configuration,the stability,and the nonlinear dynamics of the considered pipe system are determined and analyzed.The results show that for a supported pipe with the geometric imperfection of a half sinusoidal wave,the dynamical system could not lose stability even if the flow velocity reaches an extremely high value of 40.However,for a supported pipe with the geometric imperfection of one or one and a half sinusoidal waves,the first-mode buckling instability would take place at high flow velocity.Moreover,based on a further parametric analysis,the effects of the amplitude of the geometric imperfection and the aspect ratio of the pipe on the static deformation,the critical flow velocity for buckling instability,and the nonlinear responses of the supported pipes with geometric imperfections are analyzed.

Hooke and Jeeves algorithm for linear support vector machine

Coordinate descent method is a unconstrained optimization technique. When it is applied to support vector machine （SVM）, at each step the method updates one component of w by solving a one-variable sub-problem while fixing other components. All components of w update after one iteration. Then go to next iteration. Though the method converges and converges fast in the beginning, it converges slow for final convergence. To improve the speed of final convergence of coordinate descent method, Hooke and Jeeves algorithm which adds pattern search after every iteration in coordinate descent method was applied to SVM and a global Newton algorithm was used to solve one-variable subproblems. We proved the convergence of the algorithm. Experimental results show Hooke and Jeeves＇ method does accelerate convergence specially for final convergence and achieves higher testing accuracy more quickly in classification.

半市场化社区互助养老:农村老年人照料中的集体统筹与实践定位

互助养老实践打破了纯福利型和纯市场化养老模式存在的弊端,但在服务对象和服务内容上仍然存在一定不足。半市场化社区互助养老把市场和社区要素同时纳入,依托村社集体发挥公共角色功能,为高龄老人推荐低龄老人资源,提供低于市场价的半市场化养老服务,成为当前人口老龄化背景下的合适选择。在半市场化社区养老实践中,村社集体不但能够对内外部养老资源进行整合和社会动员,还可以介入养老服务过程,进行居间协调公证、监督养老服务质量、保护照料双方合法权益,强化互助养老的公益属性。半市场化社区互助养老以集体统筹为核心,通过统合政府、市场和家庭等多元主体的角色,为村庄老年人搭建起低成本、高福利的互助养老公共平台。

准确把握新时代促进区域协调发展的实践路径

区域协调发展是新时代推动我国经济高质量发展的重要任务,为中国式现代化提供了必要的空间体系支撑。基于习近平关于区域协调发展的重要论述,从目标导向、战略思路和配套政策三个维度分析新时代我国促进区域协调发展的战略框架,并以此为基础探讨促进区域协调发展的实践路径意义重大。新时代我国区域协调发展的目标导向是区域经济效率提升、社会发展公平与主体功能优化的有机统一,与这一多元目标导向相适应的战略思路是尊重经济规律、发挥比较优势、完善空间治理和保障民生底线。而要使上述战略思路能够得到有效实施,还需要完善相应的配套政策设计,具体包括区域经济发展型政策、民生保障型政策与功能支撑型政策。

级联型混合直流与UPFC的柔性潮流协调控制策略

级联型混合直流输电系统具有能抑制换相失败、传输大容量功率的优势。但当级联型混合直流低端模块化多电平换流器(MMC)采用主从控制时,若系统发生交直流故障或负荷突增,可能会产生电流不平衡问题,导致受端交流侧功率出现大范围反向传输及电压支撑能力下降。为解决该问题并增强受端电网的稳定性,针对级联型混合直流输电系统,提出一种基于统一潮流控制器(UPFC)的柔性潮流协调控制策略。研究了基于柔性交流输电(FACTS)设备统一潮流控制器(UPFC)的级联型混合直流系统柔性潮流控制特性,针对系统故障及大扰动时出现的功率返送及电压稳定性问题,提出基于UPFC的频率支撑策略和基于动态限幅的电压支撑策略。该策略将送端侧故障带来的功率扰动转移到受端交流系统UPFC所在线路,利用UPFC功率补偿能力进行协调,同时基于动态限幅控制策略,采用无功优先控制方式提高换流站无功输出能力。最后,在PSCAD–EMTDC平台搭建了含受端交流系统的级联型混合直流输电系统模型。首先,仿真了LCC直流电流指令值下降过程,结果表明,本文所提基于UPFC的协调控制策略可以有效地减小交流系统频率波动,抑制功率返送现象;其次,仿真了系统负荷突增过程,验证了动态限幅控制策略能更好地提升MMC对交流系统的电压支撑能力;最后,仿真了连锁故障过程,结果表明,所提协调控制策略能有效地实现对系统频率和电压支撑,抑制功率波动,提高了级联型混合直流系统及受端电网的稳定性。因此,本文提出的级联型混合直流与UPFC的柔性潮流协调控制策略具有有效性和可行性。

基于海上风力发电机组中虚拟飞轮储能系统的频率支撑协调控制策略

针对海上风力发电场并入电网导致电网等效惯量下降问题,提出基于海上风力发电机组(OWTs)中虚拟飞轮储能系统(VFESS)的频率支撑协调控制策略,并利用遗传算法优化VFESS吸收和释放功率的曲线。首先,OWTs采用宽转速运行控制方法形成VFESS,通过释放和吸收能量来短时支撑电网频率;然后,考虑负荷扰动、VFESS存储容量、同步发电机组一次调频时间等条件后,利用遗传算法优化VFESS释放和吸收能量的功率曲线,以实现电力系统频率跌落幅度最小、频率变化率最小的目标。最后,算例分析表明采用该方法的OWTs能提供短时频率支撑,减小电力系统低频减载装置动作次数。

计及分布式光伏和储能主动支撑的配电网日前日内协调优化运行策略

为充分挖掘分布式光伏与储能对配电网的主动支撑能力,提高配电网运行效益与供电质量,提出计及分布式光伏和储能主动支撑的配电网日前日内协调优化运行策略。考虑到光伏和负荷预测误差所带来的调度成本风险,采用条件风险价值的方法对其进行量化。日前优化模型以配电网运行成本与成本风险最小为优化目标,制定日前优化方案,为日内优化提供参考;日内优化模型对分布式光伏与储能的有功无功功率进行调度,以加权电压偏差、线路损耗、储能有功功率偏差最小为优化目标,在提升配电网供电质量的同时保证日内运行的经济性。将所提出的模型转化成便于求解的二阶锥规划模型,采用IEEE 33节点算例对所提出的策略进行验证。算例结果表明,所提出的日前日内协调优化策略充分挖掘了分布式光伏与储能的主动支撑能力,有效降低了配电网的运行成本,并对电压越限问题有明显的缓解作用。

省域国家体育产业基地集聚与体育产业发展耦合协调研究

该研究运用耦合协调度模型、TOPSIS模型和面板回归模型,对省域国家体育产业基地集聚与体育产业发展耦合协调度及影响因素进行了实证分析。研究显示:(1)省域国家体育产业基地集聚与体育产业发展耦合协调度一般呈正比关系,但也存在集聚程度高而耦合协调度小、集聚程度相同但耦合协调度不同的情形。(2)财政支出对国家体育产业示范基地集聚与体育产业发展耦合协调度的影响显著为正;旅游景区、财政支出和体育行业发展对国家体育产业示范单位集聚与体育产业发展耦合协调度的影响显著为正;体育行业发展和旅游景区对国家体育产业示范项目集聚与体育产业发展耦合协调度的影响显著为正;GDP对3种类型国家体育产业基地集聚与体育产业发展耦合协调度的影响均不显著;年末人口数对3种类型国家体育产业基地集聚与体育产业发展耦合协调度的影响均显著为负。因此,该研究建议应分区域分类型发展国家体育产业基地;加大财政扶持力度;营造浓郁的体育行业发展氛围;增强景区体育旅游开发力度。

Analytical study on pretensioned bolt-cable combined support of large cross-section tunnel

To study the mechanical responses of large cross-section tunnel reinforced by pretensioned rock bolts and anchor cables, an analytical model is proposed. Considering the interaction between rock mass and bolt-cable support, the strain softening characteristic of rock mass, the elastic-plastic characteristic of bolt-cable support, and the delay effect of installation are considered in the model. To solve the different mechanical cases of tunneling reinforced by bolt-cable support, an analytical approach has been put forward to get the solutions of stress and displacement associated with tunneling. The proposed analytical model is verified by numerical simulation. Moreover, parametric analysis is performed to study the effects of pretension force,cross-section area, length, and supporting density of bolt-cable support on tunnel reinforcement, which can provide references for determining these parameters in tunnel design. Based on the analytical model, a new Ground Response Curve(GRC)considering the reinforcement of bolt-cable support is obtained, which shows the pretension forces and the timely installation are important in bolt-cable support. In addition, the proposed model is applied to the analysis of the Great Wall Station Tunnel, a high-speed railway tunnel with a super large cross-section, which shows that the analytical model of bolt-cable support was a useful tool for preliminary design of large cross-section tunnel.

考虑风电运行轨迹与场景划分的场级主动调压优化控制策略

传统风电场跟随主站电压指令调节的方式容易导致站内无功源频繁波动、站内无功裕度不足,影响风电场的调压能力。为此提出了一种考虑风电运行轨迹与场景划分的场级主动调压优化控制策略。首先,基于风电场功率预测数据和有功–电压灵敏度曲线,绘制并网点电压波动轨迹,结合AVC子站接收到的电压指令,协调风机和SVG的无功输出,有效降低了无功设备的调节频次。其次,根据电压跌落幅度划分详细运行场景,通过调整SVG的控制模式,有效抑制了电网电压的大幅波动。最后,构建了包含AVC功率控制器的仿真测试平台,验证对比了所提方法相对于传统风电场AVC控制策略在降低无功调节频次、提升无功裕度、主动电压支撑方面的效果,为实现风电场主动调压提供了新的解决思路。