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.     

小型绝对式金属光电编码盘

为了提高光电编码器的抗强冲击振动性能,设计了一种新型的小型绝对式金属光电编码盘.首先介绍了小型金属光电编码器的工作原理;然后采用单圈循环格雷码的编码方式,在1圈码道上实现0°～360°的全量程绝对编码,设计出绝对式金属码盘;最后依据金属码盘码道的排列方式及精码、粗码信息的采集要求设计出金属狭缝盘.码盘及狭缝盘基底材料采用不锈钢,通过采用电子学细分技术、精粗校正可使编码器分辨力达到5.27″.小型绝对式金属光电编码器具有成本低、抗冲击性强、分辨力高等特点,在强冲击、强振动工作环境及对体积质量有严苛要求的场合具有很高的应用价值.     

单码道绝对式角度编码器的编码及解码原理

研究了绝对式角度编码器的编码原理及解码方法.在分析国外已有编码原理的基础上,提出了一种新的编码和解码方法来确定编码器参考线的位置.使用码区编号的概念后,使得编码器的原理变得非常简单CCD传感器获取至少一个码区的编码后,依据该码区内相邻条码标识符间的关系获得码区编号,即可以得到每个条码的粗测值;由CCD传感器每个像素代表的角度值及码区内每个条码至参考线的像素可以获得该条码的精测值,将粗测值和精测值组合成参考线的最后测量结果.这里还研究了条码总数N,码区内条码个数m和条码种类k间的关系,并以单码道绝对式角度编码器为例对编码器的理论精度进行了估计.     

双角度编码器超精密转台测角误差校准

为了提高超精密角度计量转台的测量精度,对转台所用编码器分度误差与细分误差的校准展开研究。首先,介绍了转台的结构,设计了方便进行相互比对的双角度编码器测角系统并描述了其多读数头布置方式。然后,基于直接比较法与自校准法进行了双编码器分度误差的快速、高精度校准。最后,借助精密电容式位移传感器测量系统,利用比较法检测了两套编码器各读数头的单信号周期测量误差。校准结果显示:采用双读数头均布的第一套编码器的分度误差为±0.27″,细分误差在±0.1″以内;基于四读数头均布方式进行测量的第二套编码器分度误差为±0.17″,细分误差在±0.2″以内;两套编码器的测量精度皆为亚角秒级。双编码器相互比对的校准方式有助于对转台的测角误差进行全面、准确地评估。     

基于DSP与FPGA的电容绝对式编码器的设计北大核心CSCD

为了解决绝对式编码器的编码盘复杂,增量式编码器不能获取绝对位置信息的问题,设计了一种具有2组码道的非接触角度测量的电容式旋转编码器。编码器包括2个定子和1个转子,由FPGA产生的4路相位差90°的高频方波信号作用在定子的发射极上,转子具有正弦轮廓,可将角度位置编码为基于正交调制的相位/频率调制信号,然后利用FPGA和DSP将调制信号数字化解码到角位置,最后通过RS485将数字角度位置传输到计算机上,实现了绝对角位移的在线检测。实验结果表明:设计的编码器工作可靠,测量稳定。     

旋转变压器数据融合与误差补偿的FPGA实现

为提高双通道多极旋转变压器测角系统的精度,提出了基于查表原理的粗、精通道测角数据融合方法。该方法降低了数据融合技术对粗通道旋转变压器原始测角精度的要求,并针对融合后测角误差曲线建立了基于三角函数拟合的误差补偿函数,在FPGA中实现了数据融合和误差补偿的快速计算,且搭建了双通道多极旋转变压器标定实验平台。     

单圈绝对式电子经纬仪测角信号处理

为实现快速、高精度角位移测量,提出了一种单圈绝对式电子经纬仪测角信号处理算法。只需刻画脉冲左右边沿在阈值附近各2个采样点就可以快速估计出脉冲宽度和脉冲中心坐标;对现有文献细分方法进行改进,给出了基于多组刻画脉冲中心求解高分辨力细分角的公式;并对算法时间复杂度和抗噪声性能分别进行了分析与仿真。实验结果表明,本方法在水平方向上测角误差标准差仅为2.5″,平均每秒钟可测角输出25次,具有实现简单、只需较少计算量就可以获得较高测量精度的优点。研究结果可以为单圈绝对式电子经纬仪、全站仪提供一种新的测角信号处理实用方法。     

高分辨力光电轴角编码器分辨力和精度的检测

采用微动螺杆、斜面、正弦杠杆等四级缩小原理、产生标准的微量角，测量高分辨力光电轴角编码器的分辨力和细分误差，并用直接比较法测定编码器的测角精度和进行数据处理。     

莫尔条纹信号的数字锁相倍频系统

为实现对莫尔条纹信号的高倍动态细分,提出了莫尔条纹信号数字锁相倍频的细分方法,并设计了基于CPLD芯片的数字锁相倍频系统.该系统将莫尔条纹原始信号处理成方波信号,采用全数字倍频系统对其进行锁相倍频.首先利用鉴频/鉴相器对编码器信号进行鉴别,得到倍频控制字和相位差;然后将倍频控制字送入数控振荡器,实现对原始信号的高倍倍频,同时保证了新生倍频信号与原始信号的相位同步;最后将数控振荡器输出的倍频信号经过N分频,反馈回鉴频/鉴相器,并利用相位差进行相位调整.经过实验证明,系统成功实现了对编码器信号的32768倍的细分.倍频电路全部在CPLD芯片中编程实现,其动态特性好,提高了对编码器信号的跟随速度,避免了机械上对精码码道的刻画、电子学上对精粗码校正及A/D转换中量化等的误差;并且克服了传统模拟倍频方法的响应时间较长、易受温度和电网电压波动影响、存在直流零点漂移及部件饱和等缺欠.     

伪随机码在绝对式光电轴角编码器中的应用

介绍了中国光电轴角编码器制造业中新出现的一种绝对式编码器,伪随机码绝对式光电轴角编码器.阐述了伪随机码绝对式光电轴角编码器的编码方法、技术要点及特点.伪随机码绝对式编码器采用M序列伪随机码作为编码方法,采用双狭缝技术进行分时位置读取,并采用ROM元件进行译码输出.伪随机码可以在一条码道上存储多位信息,多位码盘只需要一条码道,极大限度缩小了码盘直径,为国内生产小型化的多位绝对式编码器开辟了新途径.     

Minimal Realization of Linear Graph Models for Multi-physics Systems

An engineering system may consist of several different types of components,belonging to such physical"domains"as mechanical,electrical,fluid,and thermal.It is t...     

Quantum Cooperative Robotics and Autonomy

The intersection of Quantum Technologies and Robotics Autonomy is explored in the present paper.The two areas are brought together in establishing an interdisci...     

考虑进油孔有限长滑动轴承油膜力的近似解析解

针对具有进油孔的有限长滑动轴承油膜力求解问题,采用变分原理和分离变量法,求得了有限长滑动轴承油膜压力分布的近似解析表达式。将油膜压力分布的近似解析表达式在油膜存在区域上进行积分,即得到了油膜力。将提出的计算有限长滑动轴承油膜力方法与无限长轴承模型、有限元方法的计算结果进行了比较,发现了提出的方法与有限元方法的计算结果很接近。最后,研究了进油孔位置和进油压力对油膜存在区域、油膜力等的影响,研究结果表明进油孔位置和进油压力对油膜存在区域和油膜力有较大的影响。     

三绕组变压器的双绕组等效建模及在Matpower中的应用

针对实际电网存在着大量的三绕组变压器,但国际上一些著名商业软件,如BPA仿真软件、Matpower这一权威潮流计算开源软件,均只提供双绕组变压器模型,限制了其在具有三绕组变压器的电力系统中的应用的问题,潮流计算是自主开发的电力系统各种应用软件的核心模块,因此依托国际权威开源程序进行二次开发,是一种较好的选择。对Matpower要求的数据格式进行了归纳,对变压器的一般的等值电路及带理想变压器的等值电路和带标幺值的等值电路进行了分析研究,提出了三绕组变压器转换为双绕组等效模型的建模方法,使得原先只适应双绕组变压器的潮流计算软件可以适用于三绕组变压器电网的潮流计算;最后以Matpower软件为例进行了案例计算,并用PSASP仿真软件进行对比验证。研究结果证明,所提出的建模方法是有效的。     

On the Relation of Load to Average Gap in the Contact Between Surfaces with Longitudinal Roughness

A computer simulation model for the contact between longitudinally-oriented rough surfaces has been formulated. This model closely duplicates the actual surf ace contact deformation behavior by taking into account the elastic interactions between the asperities. There were no assumptions made about the shapes, or any deformation behavior of the asperities, except for their obeying the laws of elasticity. The plastic deformations on the high asperity peaks were taken into account by setting a ceiling on their contact pressures at the material hardness value. The simulations used real surface profiles which were digitized from unworn circumferentially ground steel surfaces. Each pair of these profiles was mathematically combined to form an equivalent rough profile pressing against an infinitely rigid flat and having the appropriately adjusted elastic modulus. A total of 28 different pairs of profiles were used in the simulations. Each contacting pair was subjected to 30 different load levels and the local contact pressures and deformations were calculated. The contact simulations yielded some important mathematical relationships between parameters, such as the real area of contact, average gap, and average asperity load through statistical curve fitting. Two analytical functions were generated to relate the average load to average gap and the real area of contact to load.     

INTEGRAL EQUATION METHOD＇S APPLICATION IN HOLE-EDGE STRESS OF COMPOSITE MATERIAL PLATE WITH DIFFERENT SHAPED HOLES

The strength of composite plate with different hole-shapes is always one of the most important but complicated issues in the application of the composite material. The holes will lead to mutations and discontinuity to the structure. So the hole-edge stress concentration is always a serious phenomenon. And the phenomenon makes the structure strength decrease very quickly to form dangerous weak points. Most partial damage begins from these weak points. According to the complex variable functions theory, the accurate boundary condition of composite plate with different hole-shapes is founded by conformal mapping method to settle the boundary condition problem of complex hole-shapes. Composite plate with commonly hole-shapes in engineering is studied by several complex variable stress fimction. The boundary integral equations are founded based on exact boundary conditions. Then the exact hole-edge stress analytic solution of composite plate with rectangle holes and wing manholes is resolved. Both of offset axis loadings and its influences on the stress concentration coefficient of the hole-edge are discussed. And comparisons of different loads along various offset axis on the hole-edge stress distribution of orthotropic plate with rectangle hole or wing manhole are made. It can be concluded that hole-edge with continuous variable curvatures might help to decrease the stress concentration coefficient; and smaller angle of outer load and fiber can decrease the stress peak value.     

电站锅炉模糊风险评价方法研究与应用

针对电站锅炉风险等级评价问题,将模糊综合评价技术应用到电站锅炉风险等级评价中。开展了电站锅炉失效影响因素及模糊评价因素的重要程度分析,建立了一套科学合理适于在线评价的电站锅炉风险评价体系,提出了模糊综合评价技术与改进的模糊层次分析法相结合的模糊风险评价方法,利用改进的模糊层次分析法计算了指标体系中各层指标权重。对某一台电站锅炉的实际运行工况影响子因素进行了模糊风险评价,采用模糊合成算子进行模糊综合运算得到电了站锅炉运行工况影响子因素的评价向量。研究结果表明:电站锅炉的运行工况影响子因素的风险评价等级为第6级,失效可能性等级为小,该电站锅炉运行工况良好。     

Short-Term Relay Quality Prediction Algorithm Based on Long and Short-Term Memory

The fraction defective of semi-finished products is predicted to optimize the process of relay production lines, by which production quality and productivity ar...     

End-to-End Multiview Gesture Recognition for Autonomous Car Parking System

The use of hand gestures can be the most intuitive human-machine interaction medium.The early approaches for hand gesture recognition used device-based methods....     

Non-monotonic material contrast in scanning ion and scanning electron images

30 keV Ga⁺ focused ion beam induced secondary electron (iSE) imaging was used to determine the relative contrast between several materials. The iSE signal compared from C, Si, Al, Ti, Cr, Ni, Cu, Mo, Ag, and W metal layers does not decrease with an increase in target atomic number Z₂, and shows a non-monotonic relationship between contrast and Z₂. The non-monotonic relationship is attributed to periodic fluctuations of the stopping power and sputter yield inherent to the ion–solid interactions. In addition, material contrast from electron-induced secondary electron (eSE) and backscattered electron (BSE) images using scanning electron microscopy (SEM) also shows non-monotonic contrast as a function of Z₂, following the periodic behavior of the stopping power for electron–solid interactions. A comparison of the iSE and eSE results shows similar relative contrast between the metal layers, and not complementary contrast as conventionally understood. These similarities in the contrast behavior can be attributed to similarities in the periodic and non-monotonic function defined by incident particle–solid interaction theory.