电动缸性能参数测试系统设计

针对现有的电动缸测试系统和测试方法不能满足电动缸产品出厂参数快速测量的问题,研发了一套以PC机作为上位机,雷赛DMC5480运动控制卡作为核心控制器,高精度磁栅尺为检测装置的电动缸性能参数测试系统。根据测试需求设计了开放式电动缸测试系统、测试方法和功能测试模块;结合数据测量装置,基于VB和API函数研发了开放式电动缸自动测试系统软件平台,包括电动缸的位置精度、回程误差、重复定位精度、误差分析与补偿及跟随误差测试等功能模块。该测试系统成功应用于某公司电动缸出厂参数快速测量。     

玉米区域试验中误差方差的异质性及其对品种评价的影响

为了研究我国玉米区域试验中误差方差的异质性存在状况及其对品种评价的作用, 以2003-2006年东北和华北16组玉米区域试验资料为依据,对玉米区域试验各环境试验误差方差差异状况及误差方差同质模型和异质模型的拟合效果进行了验证,并对品种效应差异显著性测验在误差同质模型和误差异质模型分析结果的差异状况进行了比较。结果表明,在分析的所有试验中,试验误差方差在环境间具有较大差异;误差方差异质模型比误差方差同质模型对试验数据拟合效果普遍较好;模型是否考虑误差方差的异质性对品种-环境交互效应测验结果有较大影响,而对品种主效应测验结果影响极小;误差方差异质模型比误差方差同质模型测验效率高。     

自适应加权最小二乘支持向量机的空调负荷预测

为了提高建筑空调负荷的预测精度,在分析空调负荷主要影响因素的基础上提出了一种基于自适应加权最小二乘支持向量机(AWLS-SVM)的建筑空调负荷预测方法。该方法根据预测误差的统计特性,采用基于改进正态分布加权规则,自适应地赋予每个建模样本不同的权值,以克服异常样本点对模型性能的影响。建模过程中采用粒子群优化(PSO)算法对模型参数进行优化,以进一步提高模型预测精度。基于DeST模拟数据将AWLS-SVM方法应用于南方地区某办公建筑的逐时空调负荷预测中,并与径向基神经网络(RBFNN)模型、LS-SVM模型及WLS-SVM模型作比较,其平均预测绝对误差分别降低了51.84 %、13.95 %和3.24 %,并进一步基于实际空调负荷数据将该方法应用于另一办公建筑的逐日空调负荷预测中。预测结果表明：AWLS-SVM预测的累积负荷误差为4.56 MW,亦优于其他3类模型,证明了AWLS-SVM具有较高的预测精度和较好的泛化能力,是建筑空调负荷预测的一种有效方法。     

企业内部可追溯体系的建立

可追溯体系的建立有助于增强企业识别产品的历史、应用和位置的能力。在满足国际标准GB/T22000-2006(等同于ISO22000∶2005)的基础上,介绍企业内部如何建立自己的可追溯体系,同时介绍了作为可追溯体系建立基础的可追溯单元的识别与建立,以及可追溯单元在企业内部各操作步骤的变化及由此带来的相关信息传递和沟通的管理。可追溯体系的建立,使得食品链间及企业内部的沟通更加透明和有效,也可提高企业内部的工作效率。     

用于齿面扭曲消减的齿向修形曲线设计方法

针对蜗杆砂轮磨消减齿面扭曲时存在成本高、效率低等问题,探讨在设计阶段消减齿面扭曲的途径。首先,基于蜗杆砂轮磨齿时的接触迹分析,给出了一种齿面扭曲的计算方法,分析了鼓形量及螺旋角对扭曲量的影响;其次,提出一种常用鼓形齿修形曲线的改进设计方法,将修形曲线分成三段,分别计算齿向左右两段各处扭曲量。在满足齿轮设计要求的前提下,通过调整三段曲线的比例因子以及各处的鼓形量,实现齿面扭曲量的消减。计算实例表明,该方法可有效消减齿面扭曲现象,减小齿向修形误差。     

基于高光谱的水稻土有机质含量估算研究

利用高光谱技术可实现土壤有机质含量的快速、精确反演。然而运用不同的光谱预处理算法及建模方法获取的模型预测精度及稳定性不同。为了选取最佳土壤有机质估算模型,本研究应用ASD波谱仪测定河南省潢川县水稻土的光谱数据,比较使用2种建模方法组合18种光谱预处理转换算法建立模型的反演效果。对于多元逐步回归模型和偏最小二乘模型,使用SGF3-2预处理算法均获得了最佳的预测效果,所建模型具有较小的误差和较高的精度。相比使用多元逐步回归法,使用偏最小二乘回归法可以获取更稳定的预测模型。运用偏最小二乘模型结合SGF3-2预处理算法得到了最佳的水稻土有机质含量估算模型,模型预测均方根误差RMSEv=0.036,决定系数Rv2=0.89。选择最佳的建模方法结合预处理算法,可以改进模型反演精度。本研究对比的不同方法也可以应用到类似的土壤模型选取中。     

日光节能温室卷帘机定位关键技术研究

日光节能温室是我国北方地区农作物冬季实现增产的关键措施之一,其中卷帘机的升降、天窗放风是实现其内部环境调控的重要措施,也是日常管理工作的主要内容。当前卷帘机的操作主要是人工操作,劳动强度大、费时费力且农作物不能及时得到有效合理的光照。卷帘机定位关键技术作为日光温室自动化控制系统的一个组成单元,通过研究利用角度传感器记录卷帘机运行位置的方法,提出了卷帘机运动位置控制模型,解决了日光温室模糊控制系统对卷帘机位置精准测量与控制的问题,为日光节能温室的产业化发展提供了科学的技术支撑。     

农作物种质资源本体构建研究

本体是一种能够有效提高农作物种质资源整合、共享和利用效率的组织方式。在分析传统本体构建方法的基础上,结合中国农作物种质资源自身的特点,提出结构化数据与非结构化数据相结合的半自动化本体构建方法。该方法首先基于面向对象的思想从关系数据库中抽取概念及其关系建立初始本体;然后从非结构化的网站数据中提取概念,并利用在线字典WordNet和网络百科全书Wikipedia丰富概念的语义,完善初始本体。使用本体构建工具Protégé构建了农作物种质资源本体模型。实验表明,该方法既充分利用了数据库中的资源,又考虑了非结构化数据的补充作用,减少了构建成本,本体更加完善。探讨了本体进化的途径,指出了本研究的优点和局限性。     

用模糊神经网络提高洪峰预报精度的研究

在大量研究的基础上,提出了基于模糊理论的神经网络改进算法,用来提高对洪峰的预报精度。该方法在网络训练时引入模糊理论来确定网络误差修改的程度。引入的算法增大了大值输出样本和期望输出的误差,使得网络向着提高洪峰拟合精度的方向修改权重。应用表明,改进的模糊BP神经网络能够较好的反映洪水演进机理,提高了神经网络洪水预报模型对洪峰的预报精度,保证了洪峰预报的可靠性。     

基于标记控制分水岭算法的树冠高程模型分割

树冠高程模型是树冠表面模型和数字高层模型的差值,是森林资源调查的重要数据源。笔者提出利用标记控制分水岭算法进行树冠高程模型分割的方法,首先用高斯滤波平滑树冠高程模型,对树冠边缘做初步检测,然后利用形态学重构方法进行树冠形状确认,在此基础上进行二值图像的距离变换和h-minima变换,并标记树冠顶部,最后对实验数据进行分水岭分割,实现单株木树冠边缘勾勒。误差分析表明,该方法能有效提高分割正确率,当结构元素和h-minima变换中的参数分别等于3、1.5时,树冠分割正确率为78.5%。     

Assembly fault rate analysis using grey relation and least squares support vector machines

To get the relationship between assembly fault rate and its attributes, least squares support vector machine (LSSVM)is introduced to quantitatively study assembly fault rate. Aiming at the drawbacks of assembly reliability evaluation method(AREM), the attributes of assembly-fault-rate-affecting 5M1E(Man, Machine, Material, Method, Measurement and Environment) factors obtained by AREM are improved, hence the LSSVM model with all attributes is established. To reduce the time of calculating the assembly fault rate and provide the priority for assembly reliability improvement, grey relation analysis is applied to extracting the main attributes, at the same time genetic algorithm(GA)is used for parameter optimization in LSSVM. The assembly fault rate analysis results show that the method using grey relation analysis and least square support vector machine is simpler and more accurate compared with other methods such as LSSVM model using all attributes and BP neural network using main attributes.     

Error Analysis and Modification of Virtual Instrument System

The errors of each parts of virtual instrument system, which are produced in the signals transfer process, are introduced. These errors include sensor error, signal conditioning error, data acquisition error and data dealing error, etc. The main error can be found by analyzing the influence of these errors on different virtual instrument system. The methods of errors modification are also discussed. It's an effective method that modifying system errors, especially nonlinear errors, by software. At last, as a good example, the error analysis and modification of Virtual Noise Analysis Instrument is given.     

Error Description and Modification of Virtual Measuring Instrument

When measuring, virtual instruments are inevitable to cause error damaging the precision of measuring resuits. It presents error constitution, methods of error transfer and synthesis of virtual measuring instrument. Based on the analysis of error transfer and synthesis of virtual measuring tual measuring instrument and gets the method of dealing instrument, it generalizes the error constitution formula of virwith errors. Then, errors can be modifyed.     

Calculation of lumped parameter of two-port network forvolume conduction energy transfer

Skin electrode unit is a channel through which energy can be transferred to the implanted device by volume conduction. The unit can be equivalent to lumped circuit, but so far there are no appropriate calculation methods of these circuit parameters, so variable load method based on field-circuit coupled is proposed. A skin electrode unit field circuit coupled model is established to obtain the relationship of the network parameters between voltage and current at electrode port, and the amplitude and phase of the power signal is extracted by the use of all phase FFT spectrum analysis. On this basis, equivalent circuit impedance parameters of the skin electrode unit under various conditions are obtained by the application of variable load method and the validity of the method is verified. As a result, the equivalent circuit impedance parameters obtained in this way can be used for the circuit analysis and optimization of the volume conduction energy transfer system.     

Error Transfer''s Analysis about Evaluation Criterion of a Rocket-Flight

On the basis of the accuracy evaluation's demand of single impulse radar and other ground measure equipment, model of the inherent accuracy of ballistic camera as Evaluation's comparison criterion on fairway of a Rocket-Flight are worked out. Three respects analysis follows:1) Will the criterion be able to be used? 2) In case of two laser ballistic camera having effective data ,where does the one ballistic camera be as criterion? Where does the two ballistic camera be as criterion? 3) How can the speed be evaluated? The formula ,calculation method's simplification as well as the curve figure of the error transfer of the criterion are given and analysed. The model have been successfully used in single impulse radar's accuracy evaluation. It is a typical case of the accuracy analysis.     

基于支持向量机方法的森林火险预测研究

以利用气象数据预测森林火险等级为目的,使用半正定规划建模选定支持向量机的最优核函数,依据500余条林火数据建立了支持向量回归机模型,并使用回归误差特征曲线图对比分析各个回归模型的学习效果。分析得到该自定义核函数的均方误差为1.76,支持向量数为190,约占训练数据集的1/2。结果表明,与传统的线性回归方法及基于高斯核的支持向量机相比,该预测模型具有较高的准确率并且有效的避免了过学习的现象。     

The machine setting reverse method of spiral bevel gear

The profile error correction of spiral bevel gears is difficult. To solve this problem, the inspected method of spiral bevel gears tooth surface is studied in 3906 gear measuring center. The grids of tooth surface is measured by measurement software. Taking reference tooth surface as the goal, a method of machine setting reverse using approximation algorithms is proposed, and a mathematical model is build. At last, a reverse example based on grinded spiral gear is given. The result shows that the cutting machine setting of bevel gear tooth surface can be exactly calculated.     

Pitch error measurement of high-order oval bevel gear on three dimensional measuring machine

Based on the prototype workpiece which is manufactured according to the high-order oval gear envelope method,a measurement method of high-order oval bevel gear is proposed in order to verify the correctness of design and manufacture method for this gear pair. The mathematical model of measurement and evaluation is established according to the spatial gear engagement theory. Then the coordinate point set obtained from three-dimensional measuring machine is analyzed and filtered based on the actual measurement on prototype workpiece. Therefore,the ideal element is available. And then the aberration curve of pitch curve,individual circular pitch error and accumulated error can be obtained after analyzing the point set. Finally,the conclusion that the high-order oval bevel gear pitch error evaluation method is feasible can be obtained because the measurement and analysis result dovetailed basically with the theoretic calculation result.     

风电齿轮箱传动误差分析及振动噪声预估

针对一级行星两级平行轴风电齿轮传动系统,综合考虑齿轮时变啮合刚度、啮合阻尼、传递误差等因素,建立31个自由度的弯扭轴耦合集中参数动力学模型,采用变步长Runge-Kutta法对系统动力学微分方程进行求解,得出齿轮传动系统各级传动误差;借助软件建立风电齿轮箱刚柔耦合动力学模型,并导入传动误差,采用模态叠加法求得齿轮箱轴承支反力,并将其作为声振耦合模型的边界条件,采用声学有限元法对风电齿轮箱进行振动噪声预估,并与试验结果对比分析,两者吻合良好。