地磁图数据随机误差建模与补偿

地磁图是影响地磁匹配导航性能的重要因素,其中地磁图的随机误差严重影响匹配定位精度,甚至导致误匹配。 为提 高地磁匹配性能,提出了地磁图数据随机误差建模与补偿方法。 该方法在对地磁图数据随机误差特性分析的基础上,建立数据 的非平稳时间序列模型,并将此模型作为状态方程,以实时数据为量测量,采用 Kalman 滤波方法对地磁图数据进行滤波,补偿 地磁图数据的随机误差。 通过基于滤波前后地磁图数据的导航定位实验,间接证明滤波方法的有效性。 对实际地磁图数据处 理结果表明,应用该方法滤波后的地磁图数据进行导航,其定位精度提高了 54. 7%。     

基于集员未知输入观测器的风力机桨距执行器故障诊断

风力机一般放置在恶劣的环境中,其桨距执行器极易出现故障。文中针对一类含有未知但有界干扰和噪声的风力机系统的桨距执行器故障问题,设计了集员未知输入观测器对桨距的执行器故障进行检测并分离。采用气动机理和现代辨识原理建立风力机系统模型,通过优化未知输入观测器设计对系统中的干扰解耦,基于中心对称多胞体估计不考虑故障时残差的区间包络,并将其作为残差估计的上下动态阈值,实现状态估计。在上述基础上提出了利用一组集员未知输入观测器进行故障诊断的策略。仿真结果表明,在实验过程中,文中所设计的集员未知输入观测器准确地诊断出了风力机桨距执行器的3阶和5阶线性系统在发生突变故障和缓慢时变故障的时间和位置,证明了所提故障诊断策略的有效性。     

Human error probability estimation by coupling simulator data and deterministic analysis

Operator error in diagnosis and execution of task have significant impact on Nuclear Power Plant (NPP) safety. These human errors are classified as mistakes (rule base and knowledge based errors), slip (skill based) and lapses (skill based). Depending on the time of occurrence, human errors have been categorized as i) Category ‘A’ (Pre-Initiators): actions during routine maintenance and testing wherein errors can cause equipment malfunction ii) Category ‘B’ (Initiators): actions contributing to initiating events or plant transients iii) Category ‘C’ (Post-Initiators): actions involved in operator response to an accident. There have been accidents in NPPs because of human error in an operator's diagnosis and execution of an event. These underline the need to appropriately estimate HEP in risk analysis. There are several methods that are being practiced in Probabilistic Safety Assessment (PSA) studies for quantification of human error probability. However, there is no consensus on a single method that should be used. In this paper a method for estimating HEP is proposed which is based on simulator data for a particular accident scenario. For accident scenarios, the data from real NPP control room is very sparsely available. In the absence of real data, simulator based data can be used. Simulator data is expected to provide a glimpse of probable human behavior in real accident situation even though simulator data is not a substitute for real data. The proposed methodology considers the variation in crew performance time in simulator exercise and in available time from deterministic analysis, and couples them through their respective probability distributions to obtain HEP. The emphasis is on suitability of the methodology rather than particulars of the cited example.     

Simulation based neuro-fuzzy hybrid intelligent PI control approach in four-area load frequency control of interconnected power system

This paper presents a novel control approach of hybrid neuro-fuzzy (HNF) for load frequency control (LFC) of four-area power system. The advantage of this controller is that it can handle the non-linearities, and at the same time it is faster than other existing controllers. The effectiveness of proposed controller in increasing the damping of local and inter area modes of oscillation is demonstrated in four area interconnected power system. Area-1 and area-2 consist of thermal reheat power plant whereas area-3 and area-4 consist of hydro power plant. Performance evaluation is carried out by using fuzzy, ANN, ANFIS and conventional PI and PID control approaches. The performances of the controllers are simulated using MATLAB/Simulink package. The result shows that intelligent HNF controller is having improved dynamic response and at the same time faster than ANN, fuzzy and conventional PI and PID controllers.     

烘干法数显水分测定仪测量结果不确定度分析

烘干法水分测定仪是一种基于烘干原理直接对衡量样品表面分离物或微量水分进行计量分析的仪器。文章依据JJG 658--2010《烘干法水分测定仪国家计量检定规程》中的检定方法,并按照JJF1059-1999《测量不确定度评定与表示》规范,对数字显示水分测定仪的测量结果进行不确定度分析。     

旋进旋涡流量计合成不确定度及其表示方法

随着市场对天然气需求的不断扩大,天然气公司对流量计计量准确度的要求也变得越来越高,但是流量计的测量误差却是无法避免的,而不同的误差可以通过不同的方法来进行控制或减小,其中重要的未定系统误差可以通过不确定度来确定。因此如何正确合理地求出流量计的测量不确定度是十分必要的,本文将以旋进旋涡流量计的测量不确定度的分析过程为基础,指出了在合成标准不确定度以及扩展不确定度的表示中应当值得注意的地方。     

再制造双圆弧齿轮单齿切削机床设计

目前抽油机减速器双圆弧齿轮使用一段时间后会出现单个齿破损或多个齿间隔破损的情况,现有的修复方法效率低。针对这种情况,提出设计一种对修复后的再制造双圆弧齿轮进行再加工的切削机床,验证再制造双圆弧齿轮单齿加工的可行性。结合再制造双圆弧齿轮单齿展成加工理论,对单齿加工机床的刀具运动部件、齿向螺旋进给部件、齿形展成进给部件以及工件运动部件进行设计,最终得到满足加工要求的再制造双圆弧齿轮单齿切削机床。分析再制造双圆弧齿轮单齿加工的误差后,提出一种减小再制造双圆弧齿轮轴向齿距误差的方法。     

CMT电弧增材制造316L不锈钢成形精度与组织性能分析

以冷金属过渡电弧增材制造的方法成形了316L奥氏体不锈钢单道多层薄壁件,分析了不同焊接参数下材料的成形宽度、侧面成形误差、沉积有效率以及显微组织的变化. 结果表明,随着焊接速度的减小,成形试样的宽度逐渐增大;随着热输入的增加,侧面成形误差呈先减小后增大的趋势,沉积有效率呈先增大后减小的趋势,侧面成形误差与沉积有效率的变化相反. 沉积效率越大,侧面成形误差越小,成形有效率可达到90%以上. 成形件显微组织为γ-Fe和δ铁素体,δ铁素体形貌有树枝状和蠕虫状两种. 显微硬度测试结果显示在垂直于沉积方向和平行于沉积方向硬度值变化不大,这与各方向成形材料的显微组织比较均匀有关.     

基于线性回归和神经网络的金属陶瓷激光熔覆层形貌预测

目的研究激光熔覆关键工艺参数(激光功率、扫描速度、送粉速率)与单道熔覆层宏观形貌(宽度、高度、熔池深度)之间的数量关系,以实现对WC-Co50复合熔覆层形貌的预测,从而为牙轮钻头的修复提供参考。方法设计不同的实验参数,利用4k W光纤激光器在牙轮钻头钢15MnNi4Mo表面熔覆单道WC-Co50复合涂层。采用工业显微镜观察单道熔覆层的横截面宏观形貌,并测量其三维尺寸。在上述形貌参数的基础上,分别运用多元线性回归分析和人工神经网络方法,建立关键工艺参数与熔覆层宏观形貌之间的关系模型,并将实验结果与模型预测结果进行对比。结果总体来讲,神经网络对熔覆层形貌的预测结果更为精确,平均相对误差为5.3187%;多元线性回归分析预测的平均相对误差为6.0028%。分析表明,对熔覆层宽度的预测结果最精确,两种方法的平均相对误差仅为1.2999%;对高度及熔池深度的预测结果稍差,平均相对误差分别为8.0586%和7.6237%。结论两种预测方法都具有较高的精度,但神经网络法函数关系不明确,运算过程复杂,需要通过进一步的算法优化来提高预测精度。     

数控机床的热误差建模与补偿研究

数控机床的热变形误差是影响其加工精度的主要因素。针对当前机床热误差难以解决的问题,提出一种融合模糊聚类理论、灰色关联理论和多元线性回归理论的热误差建模及补偿原理,通过应用于实验室自主研制的AGPM,经机床温度场的测点优化分析、多元线性回归求解,建立了精确的热误差补偿模型。经补偿验证,该原理理论正确、简单易行、稳定可靠,可以大幅减小机床的热变形误差。