基于高频注入的永磁同步电机参数辨识策略

永磁同步电机高性能控制依赖电机参数和磁极初始位置的准确性,辨识磁极初始位置可以保证无位置传感器矢量控制启动过程的平稳性。传统的参数辨识方法辨识过程较为复杂或者精度不高,本文提出了一种易于实现的高频注入控制算法,通过注入高频电压,提取高频电流,就可以直接快速辨识出永磁同步电机电感,再通过注入两个脉冲电压矢量,就可以辨识磁极初始位置。这种方式辨识精度高,快速性好,工程实现方便,而且不需要转动电机,具有广泛的实用性。     

基于大数据的铁路工程投标企业异常行为预警研究

基于铁路工程电子招投标积累的海量数据,识别预警具有异常行为的铁路工程投标企业。运用社团结构检测分析识别具有抱团行为的投标企业;再通过函数拟合预测投标企业中标次数,根据实际值与预测值的标准残差所落置信区间范围,分析识别中标次数异常的投标企业;最后综合分析2种方法的结果,构建铁路工程投标企业异常行为分级预警模型,识别具有串围标嫌疑的企业并分级预警。研究结果表明:基于铁路工程电子招投标大数据,综合社团结构检测和函数拟合分析两种方法,可以有效识别预警铁路工程投标企业的异常行为。     

次级通道在线辨识的双层隔振系统振动主动控制

次级通道离线辨识限制了自适应控制的适用性,次级通道发生突变后,离线辨识的控制效果很差。本文在Eriksson在线辨识模型的基础上,通过变步长和调整滤波器阶数,对在线辨识模型进行优化,并将其运用到双层隔振系统。将白噪声引入控制输出端,在保证系统稳定的前提下调整滤波器阶数,以变步长LMS算法调整FIR滤波器权值系数,为次级通道进行实时在线参数辨识。仿真结果表明,优化后的次级通道在线辨识算法能有效抑制单频振动和多频振动,次级通道发生突变时,在线辨识控制效果优于离线辨识。     

闸楼房无人值守系统的设计与实现

主要介绍闸楼房无人值守系统的设计、实现及运用效果.该系统主要利用射频识别和计算机技术,通过在机车上安装射频IC卡,在车务部门与机务段分界点的闸楼房安装扫描读卡装置,实现机车出入信息的自动识别、采集与处理,并利用现有网络通道,实现铁路局、车务部门和机务段3级网络的信息共享,使各级运输管理人员都能够实时掌握机车出入及运用情况.     

交通行为建模－问题与机会

研究交通行为是科学规划与管理交通系统的基础.数学模型是整体把握交通行为的重 要工具.目前的交通行为模型注重适用性.而欠缺理论上的严密性,回顾了交通模型中的几个 经典成就,指出交通科学中还有许多问题等待解决,介绍了国际上传播交通模型的主要媒体.     

基于嵌入式服务器的多模航行信息接收系统设计

文章设计了一种基于嵌入式服务器的多模航行信息接收系统,具有自动接收船舶识别信息、航行告警信息和气象传真信息的功能,同时具备了通过多功能显示器和热敏打印装置进行集中显示和图像打印的功能。文中给出了系统硬件组态及相应软件设计流程,测试和试用结果显示系统具有极高可靠性和实用性,具有很大的市场推广价值。     

Surfer and Beachgoer Responsiveness to Coastal Water Quality Warnings

Fecal contamination of coastal waters has led local public health agencies to issue tens of thousands of beach advisories annually and to advise against ocean swimming and surfing for 72 hours following a rain. The responsiveness of recreationists to beach advisories and the “72 hour rule” is estimated by merging four years of multi-daily surfer and beachgoer counts at one beach in Southern California with hourly data on beach advisories, recent precipitation, meteorological conditions, and the UCSB academic calendar. Both surfing and beach-going decreased significantly following rainfall in response to the 72 hour rule, showing that recreationists are willing to engage in health risk-reducing avoiding behavior. However, neither surfing nor beach-going decreased significantly during beach advisories. Surfers were significantly more responsive to beach advisories during dry periods than during wet periods, consistent with the hypothesis that recreationists are most likely to respond to a risk warning that they believe provides accurate and additional health risk information beyond what they can observe personally. Additional studies of beach advisories elsewhere could clarify whether responsiveness to beach advisories varies by recreationist demographic, recreational activity, frequency of advisories, or frequency of repeat visitation. Increasing the accuracy and additional information provided by beach advisories, as proposed by numerous authors, could lead to increased responsiveness.     

考虑决策过程与潜在异质性的居民通勤选择行为研究

传统研究对居民通勤决策过程的动态性及微观心理偏好关注不足，为此利用潜在类别模型表征居民通勤决策的潜在异质性，从动态决策角度出发，构建可以体现偏好动态演进过程的决策场理论模型。该模型对不同潜在类别设置差异化的属性注意力权重，表征不同子市场用户动态偏好的差异性和相同子市场用户偏好似而不同的特征，同时实现用户分类和动态决策过程分析，改进传统决策场理论对个体偏好异质性表征不足的缺陷。对成都市轨道交通车站附近居民进行实证研究，结果表明，通勤居民可以细分为“商务需求型”“追求效率型”“经济环保型”“保守型”这4类，各类别间的备选方案初始偏好、属性关注程度均呈现显著差异。通过Matlab仿真实现对个体决策结果、微观偏好进化过程及非理性效应的预测和分析，验证了本文方法的有效性。     

Mannich反应制取的SPN衍生物的摩擦学研究

通过Mannich合成了一种含苄胺的SPN衍生物,在四球摩擦磨损试验机上研究了它们作为加氢油添加剂的摩擦学性能.实验结果表明,该类化合物能较好地提高基础油的极压抗磨性能.用X-射线光电子能谱(XPS)分析了钢球磨损表面典型元素的化学状态,结果表明,在摩擦过程中,钢球表面形成了一层合硫,磷无机膜和含氮有机膜组成的复合膜,...     

Hinge joint damage identification method of soft yoke mooring system based on multibody dynamic modeling and structural monitoring data

Soft yoke mooring system (SYMs) is a single-point mooring system used in shallow water oil and gas development. In general, SYMs consists of mooring framework support, mooring legs, yoke, and single-point turret and it forms a multibody dynamic system with 13 hinge joint structures such as universal joints and thrust bearings. The hinge joint is one of the key components of SYMs; therefore, it is necessary to accurately evaluate the operating behavior of the hinge joints. In this study, real-time damage identification is conducted based on the multibody dynamic features of the SYMs. First, a long-term monitoring strategy for the prototype application is developed based on the multibody governing equations of the SYMs. The motion behaviors and stress state of the hinge joints and bodies are calculated using prototype monitoring data. A hinge joint damage identification based on the virtual moment is proposed by considering the changes in the friction coefficient in the damage state. The virtual moment method is used to transform the damage identification problem of the SYMs into a problem of seeking the optimal solution to the dynamics identification function. Genetic algorithm (GA) is implemented to seek the optimal solution of the friction coefficient of each hinge joint. A large-scale model testing system of the SYMs is established to perform the damage identification of the bottom hinge joints of the SYMs. The results show that the proposed method can effectively identify the damage degree and position of the hinge joints of the SYMs and provide a real-time warning system for the in-service operation of the SYMs.