XGBoost机器学习在光电编码器误差补偿中的应用

光电编码器检测系统的误差主要受基准光电编码器测角误差、数据采集误差、检测系统同轴误差影响。其中，基准光电编码器的测角误差可进行补偿。因此设计了一种基于极度梯度提升树（extreme gradient boosting,XGBoost）机器学习的算法用来补偿基准光电编码器的误差。经该算法补偿后，静态精度提高了35倍，标准差由3.62″减小至0.13″，最大误差值由5.53″降低至0.39″。与传统的误差反传（back progagation,BP）神经网络算法以及径向基函数（radial basis function,RBF）神经网络算法补偿效果相比，XGBoost的补偿效果更优。XGBoost机器学习算法有效降低了基准光电编码器的测量误差，提高了光电编码器检测系统的检测精度。     

高精度光电轴角编码器轴系精度设计与测量

为实现高精度光电轴角编码器的精度 ,提出了光电轴角编码器的轴系精度指标 ,并对影响光电轴角编码器精度的主要因素—轴系晃动量的分离测量方法进行了讨论     

光电编码器用计算机自动检测装置

描述的是一个光电编码器的测试装置，该系统采用计算机对光电编码器的输出信号进行自动采集与处理，能有效、全面、可靠地对光电编码器的误差进行检测。阐述了该装置的原理及其硬件和软件的构成，并讨论了一些实际问题及解决方法。     

航天级光电编码器的信号处理系统设计

为了实现航天级光电编码器的小型化,减小航天设备的体积、重量并满足其冷备份要求,设计了具有双读数系统的航天级光电编码器信号处理系统。首先,介绍了双读数系统航天级光电编码器的精码和粗码信号处理方法以及信号处理系统的小型化和可靠性设计;然后,从光电编码器误差产生的原因及空间分布特征出发,对双读数系统航天级光电编码器进行了精度分析;最后,采用比较法,以23位高精度光电编码器作为角度基准,对该光电编码器进行了精度检测。实验结果表明:应用该信号处理系统的双读数系统光电编码器的分辨力为20″,精度σ≤30″。该系统已在工程项目中得到应用,实践表明系统的设计满足航天设备的技术要求。     

基于后验误差拟合的角位移测量误差补偿

在航天、军事、工业这些对器件的体积有着严格要求的领域,光电编码器不仅要求减小外径尺寸和重量,更要提高其测量精度。本文以光电编码器误差补偿方法为研究对象,基于后验误差拟合方法确定误差模型参数,从而实现对小型光电编码器的深度误差补偿。分析了影响光电编码器测角误差的主要因素,建立了长周期误差和短周期误差模型。然后,采用后验误差拟合算法实现了对误差模型参数的确定,提出误差补偿算法;最后,对某一小型光电编码器进行实验,验证了所提出误差补偿算法的性能。某型号光电编码器补偿前的精度为22.48″,补偿后的精度为5.82″。实验表明,采用后验误差补偿方法可以不考虑误差影响因素的大小,直接对编码器进行误差补偿,具有效率高、补偿准确等优点,极大地提高了批量生产时光电编码器产品的精度。     

高分辨力面阵图像式光电编码器的测角技术

为实现面阵图像式光电编码器的小型化及高分辨力,研究了面阵图像式光电编码器的码盘编码和基于图像处理技术的精码细分算法.首先根据光电编码器的性能指标要求设计相应的码盘尺寸;然后通过图像传感器采集随轴系转动的码盘图样;微处理器接收图像数据,通过图形识别算法得到粗码角度,并采用改进的基准线质心算法,计算亚像素级的精码角度信息.最后由粗码和精码组成光电编码器测角数据.实验结果表明,设计码盘直径为φ45 mm的面阵图像式光电编码器,在不配备光学镜头的前提下,采用研究的精码细分技术,可实现4 096份细分,测角分辨力达到5″,角度误差峰峰值为61″.该面阵图像式光电编码器和精码细分技术可以提高编码器的分辨力,缩小编码器体积,减轻重量.适用于航空航天领域对小型化光电编码器的需求.     

主精度光电轴角编码器轴系精度设计与测量

为实现高精度光电轴角编码器的精度,提出了咣电轴角编码器的轴系精度指标,并对影响光电轴角编码器精度的主要因素－轴系晃动量的分离测量方法进行了讨论。     

基于FPGA的光电编码器四倍频电路设计

分析光电编码器四倍频原理，提出了一种基于可编程逻辑器件FPGA对光电编码器输出信号倍频、鉴相、计数的具体方法，有利于提高被控对象的测量精度和控制精度。     

多传感器融合在移动机器人运动控制中的应用

本文提出一种基于T-S模型的变结构模糊神经网络直接逆模型控制器，并将其应用于移动机器人的运动控制中。利用光电编码器进行自定位。同时，用扩展卡尔曼滤波器融合多个超声波传感器的测量值，并采用回塑算法，将融合值用于复位光电编码器，不仅消除了光电编码器累积误差的影响，并能满足实时控制的要求。仿真实验说明了该方法的有效性。     

新型研齿机及其主轴控制技术的研究（下）

3·3系统主要硬件的配置3.3.回脉冲编码器采用光电旋转式脉冲编码器，每转可输出360个脉冲。图4为其结构图，随着轴的旋转，写入黑白囹形的素也旋转。通付2处缝隙的光透过或遮断，靠各自与缝隙配合的晶体管变成电流，经晚形整形而成为两个矩形波列。而之外的缝隙配合，使矩形波列输出相位错开1／4节距。电压输出型编码器，输出波形如图5所o。图4脉冲编码器结构图1.轴2.光电晶体管3.转盘（圆板）4.A相缝i.B相缝6.两相信号维图5编码器电压输出波形3.3.2数字量输入／输出子系统光隔1／O板该子系统为16通道光电隔离型1／O，能与IBM—PCXT／…     

固相微萃取和气相色谱-质谱法测定北京酱牛肉中的挥发性成分

采用顶空固相微萃取和气相色谱-质谱法（Head Space Solid Phase Microextraction Gas Chromatgraphy-Mass Spectrometry,HSSPME—GC—MS）对北京传统酱牛肉中的挥发性香气物质进行了测定,总共检测出68种风味化合物,其中包括醛类49.12%、酮类0.84%、醇类4.85%、烃类13.29%、酯类2.61%、酚醚类11.33%和含硫含氮及杂环化合物6.55%,另外还有11.41%的其它类物质,其中醛、酮和含硫含氮及杂环化合物中含有北京传统酱牛肉的主要香味成分。     

Validation of a method for composition measurement of a non-standard liquid fuel for Emission Factor evaluation

In this paper the theoretical and experimental aspects are described concerning the validation of a method for the measurement of the percentage composition of a generic liquid fuel, even though specific reference materials for instrumentation calibration are unavailable. This new method could be used for the evaluation of the Emission Factor (EF) of an unknown fuel for emission trading purposes, according to the requirements of both the juridical and technical standards. The validation of the procedure is based on the comparison of different techniques for the measurement of Gross Calorific Value (GCV), Net Calorific Value (NCV) which are quantities useful in EF evaluation; this new combination of actions established a complete and validated methodology for EF evaluation. The experimental results and uncertainty analysis show that this method is suitable for the estimation of the composition measurement and also that of GCV, NCV and EF also for non-standard liquid fuels; a comparable accuracy with respect to the methods for standard fuels has been estimated, making this method suitable for practical applications.     

螺旋锥齿轮珩磨轮的制造方法

对用于螺旋锥齿轮珩磨加工的珩磨轮模具制造的关键技术进行深入研究。介绍珩磨轮齿面准均布网格点的计算方法,通过计算这些准均布网格点及其径矢和法矢,建立齿面上每一个网格点的拨模极限导程的数学模型。通过计算齿面上这些网格点的可行的螺旋线导程,判断其交集是否为空集,并以此作为判断是否出现拨模干涉的依据。针对已经出现的拨模干涉,提出拨模导程的优化方法以及干涉的修正方案和齿面光顺过程。详细讨论金属模具的逐点成形和展成加工方法以及它们各自的适用范围和可加工性,并以刀倾法为例,阐述加工螺旋锥齿轮珩磨轮的金属凸模的计算步骤,为螺旋锥齿轮珩磨轮的制造提供理论依据。     

Qualitative criteria for dynamic buckling of imperfection sensitive nonconservative systems

A qualitative dynamic buckling analysis of imperfection-sensitive non-conservative dissipative systems under path-dependent loading in regions of divergence is presented. Despite the lack of potential for this type of loading a total energy-balance equation allows us to establish a sufficient criterion for dynamic buckling, the counterpart of that valid for potential systems. Moreover, using energy and geometrical considerations for the channel of motion, one can obtain for a 2-DOF model dynamic buckling loads (DBLs) which are practically exact for vanishing but non-zero damping and very accurate for non-zero damping. Numerical results show the efficiency and reliability of the proposed qualitative analysis.     

Controlled serial grinding for high-resolution three-dimensional reconstruction

This work reports an improved preparation procedure for acquiring SEM images for three‐dimensional (3D) reconstruction. The images are acquired consecutively after serial grinding and polishing. Ugelstad beads are used as landmarks for registration purposes and for determining the thickness of the abraded sections. An estimation of the bead sizes necessary for suitable thickness quantification at the corresponding spatial resolution and uncertainty is given. Shape‐based interpolation is used for filling the gaps between the cross‐sections. An indication of the distance between cross‐sections necessary for good interpolation is also given. An example of a 3D reconstructed paper volume is presented. The method is suitable for preparation of fibre and paper as well as other materials.     

A handheld support system to facilitate stereological measurements and mapping of branching structures

BranchSampler is a system for computer-assisted manual stereology written for handheld devices running Windows CE. The system has been designed specifically to streamline data collection and optimize sampling of tree-like branching structures, with particular aims of reducing user errors, saving time, and saving data in formats suited for further analysis in other software, for example, a spreadsheet. The system can be applied in a wide range of applications, from biomedical science to agriculture and horticulture. It can be applied for sampling nested generations of lung bronchioles and renal arterioles or for collection and optimizing sampling of crops for precision agriculture. Although the system has been designed specifically for sampling branching structures, it is sufficiently flexible to be used for other applications involving nested stereological designs. We describe the system specifications, software and Graphical User Interface development, functionality and application of the handheld system using four examples: (a) sampling monkey lung bronchioles for estimation of diameter and wall thickness (b) sampling rat kidney for estimating number of arteries and arterioles in a specific generation (c) mapping fruit (apple) tree yield in an orchard and (d) estimating the total leaf surface area of chrysanthemum plants in a greenhouse.     

Pseudo-vibration sensitivities for commercial laser vibrometers

Pseudo-vibration sensitivities in laser vibrometry are the consequence of measurement noise generated by surface motions other than that on-axis with the incident laser beam(s), such as transverse and tilt vibrations or rotation. Concentrating solely on commercial laser vibrometers to maximise value to the vibrometer user, this paper quantifies pseudo-vibration sensitivities for five single beam instruments (for translational vibration measurement) and two parallel beam instruments (for angular vibration measurement) across a range of surface treatments and roughnesses. Transverse, tilt and rotation sensitivities are quantified for the single beam instruments. In-plane rotation, rotation and tilt sensitivities are quantified for the parallel beam instruments. Estimates of sensitivities for parallel beam instruments based on related quantifications for single beam instruments are shown to offer order-of-magnitude agreement. Further confirmation is provided of the benefits of smaller laser beams for measurements on tilting or rotating surfaces and of larger beams for measurements on surfaces with transverse motion. For rotor vibration applications, lower sensitivities are found for a focus location on the shaft rotation axis rather than its surface. Based on experimental evidence, refinements to the test methods are suggested with a view towards the formation of a Standard. These comprise placing limits on surface flatness and rotor out-of-roundness, inclusion of agreed ranges for target displacement amplitude and rotor diameter, and acknowledgement of the importance of focus location for rotation sensitivities.     

A Surface Area Calculation and CAPP System for Non-Axisymmetric Deep Drawing Products

In this paper a surface area calculation for non-axisymmetric deep drawing products of elliptical shape was constructed for the design of blank shapes of deep drawing products by using an AutoLISP function in AutoCAD software. A computer-aided process planning (CAPP) system for rotationally symmetric deep drawing products has been developed. In this study, a CAPP system for non-axisymmetric deep drawing products of elliptical shape was constructed using process sequence design. The system developed consists of four modules. The first is the recognition of shape module for recognising non-axisymmetric products. The second is a 3D modelling module for calculating the surface area for non-axisymmetric products. The third is a blank design module for creating an oval-shaped blank with an identical surface area. The fourth is a process planning module based on production rules that play the most important role in an expert system for manufacturing. The production rules are generated and upgraded by interviewing field engineers. The drawing coefficient, the punch and die radii for elliptical shape products are considered as the main design parameters. The suitability of this system was verified by applying it to a real deep drawing product. This surface area calculation and CAPP system should be very useful for reducing the lead-time for manufacturing and for improving the accuracy of products.     

第四十六讲工业物联网技术及标准体系

针对当前工业物联网系统中存在的异构性和互操作性问题,本文介绍了一种工业物联网技术及标准体系,该标准体系中包括了工业物联网身份标识、工业物联网应用属性协议、工业物联网服务协议以及工业物联网互操作协议四项标准。该系列标准的制定将有利于提高工业物联网的运行效率和互操作性,为工业物联网发展提供支持。     

影响凸轮检测精度的问题与对策

针对目前国内在发动机凸轮检测中 ,选择检测基准、确定检测位置、测头切换、最小判别等方面存在的带有普遍性的影响凸轮检测准确性的问题进行了分析 ,并参照 GB/T1 1 82 -1 996和 GB/T1 6671 - 1 996,以“最小条件”为依据 ,从发动机凸轮升程和转角是非线性函数关系入手 ,对选择凸轮检测基准原则、确定凸轮检测位置 (求解检测起始转角 )方法、凸轮升程检测数据的处理、凸轮升程合格性的判定等进行了论述