光通信粗瞄系统莫尔条纹信号正弦性补偿方法

为了保证光通信终端的精确对准,抑制编码器莫尔条纹正弦性偏差引入的细分误差,设计了基于经验模态分解(empir-ical mode decomposition,EMD)的正弦性修正方法。首先,介绍了卫星光通信终端跟瞄系统的组成与工作原理。接着,分析了莫尔条纹正弦偏差给系统带来的细分误差并给出满足工程需求的正弦性阈值。然后,在阐述EMD分解原理的基础上,给出了基于EMD的正弦性修正方法,该方法利用编码器自身粗码信息计算转速,从而确定精码莫尔条纹信号的基波频率值,并采用EMD分解在原始信号中提取与该值相匹配的基波分量。最后,对该方法进行了原理和转速自适应性仿真,并应用到去掉光学滤波镜片后的粗瞄回路编码器中。仿真及实验结果表明:在光通信终端的各工作转速下,修正后的莫尔条纹正弦性均小于0.85%,满足细分要求;修正后的精码译码结果精确,编码器测角精度维持在1″以内,满足终端对准精度的要求。     

小型光电编码器细分误差校正方法

为提高小型光电编码器精度,设计了精码莫尔条纹信号细分误差校正方法.首先建立存在直流分量、幅值误差、波形畸变的精码光电信号的波形方程,然后利用牛顿迭代法将两路精码细分信号校正至标准的正弦和余弦信号,最后建立两路信号间的正交性误差模型,通过最小二乘法求解出正交性误差校正参数.运用本文的细分误差校正法对某16位小型绝对式光电编码器进行误差校正处理,经测试,细分误差峰峰值由校正前的160″减小到校正后的48″.实验结果表明:研究的误差校正方法可以有效地减小细分误差、提高编码器精度,对于研制小型化、高精度光电编码器具有重要意义.     

莫尔条纹正交偏差的智能补偿方法

提出了一种新的编码器莫尔条纹正交偏差的补偿方法及实现方式。通过比较分析,采用相关函数分析法测量各精码周期莫尔条纹的正交偏差,并基于系统自身的粗码信息,构造一种智能采样算法,保证莫尔条纹采样均匀性;在工作中对所有精码周期的莫尔条纹实行数字式实时补偿,并可以通过模式间的切换自适应地更新正交偏差补偿参数,持续地保证补偿的精确性,降低编码器在各种恶劣环境下的误码率。实验结果表明,正交偏差10度以内时,补偿后的信号正交性提高了93%以上,保证了编码器测量精度。     

提高光栅莫尔条纹信号质量的滤波方法

针对莫尔条纹信号的质量问题提出一种相位差滤波法.将指示光栅上四场裂相方式中每场细分为多个不同相位的行组合,利用行组合间的不同相位排列关系来消弱高次谐波的分量,从而提高莫尔条纹信号的质量.首先,介绍了莫尔条纹的傅里叶级数表达式,对莫尔条纹的各次谐波特性进行了分析.然后,以指示光栅的图案设计为例,阐明该滤波方法消除二次、三...     

基于FPGA的新型数字锁相倍频方法

为了克服模拟锁相倍频电路在应用过程中易受温度和电压影响、锁相时间长、存在直流零点漂移及部件饱和等缺欠,以实现对被测信号的高速高精度采样,提出了一种基于FPGA的新型数字锁相倍频方法.该方法依据锁相倍频的基本原理,通过检测被测信号的边缘计算出频率值,找到相应的指针位置,再根据产生的分频因子来控制数控振荡器的输出信号,从而完成对被采集信号的锁相倍频.经过仿真分析,验证了该方法的可行性,证明了其具有精度高、锁相速度快等优点.     

锁相倍频细分中光栅位移跟踪速度与分辨率的关系

针对光栅传感器信号细分时普遍存在的分辨率提高、位移跟踪速度下降这一现象,基于锁相倍频细分方法研究了光栅位移跟踪速度与分辨率之间的关系.以50线/mm的普通光栅尺为例,利用FPGA芯片的底层嵌入模块74297实现了对光栅信号的锁相倍频细分.研究了锁相倍频细分电路的截止频率,推导出光栅跟踪速度与分辨率的数学关系.利用QuartusⅡ软件搭建了锁相倍频细分电路,利用Simulink工具箱对该电路进行了建模和仿真,验证了所得结果的正确性,为设计高分辨率、高位移跟踪速度的数字集成化光栅数显装置奠定了基础.     

一种光栅莫尔信号数字锁相细分方法

为了保证和提高光栅传感器在动态测量过程中信号细分结果的准确性和实时性,本文提出一种新型的莫尔信号数字锁相细分方法。该方法采用开环结构,根据光栅莫尔信号的实时频率,利用小数分频方法完成对光栅莫尔信号的细分功能;开发了基于现场可编程门阵列(FPGA)的数字锁相细分电路,并对细分实现过程中的电路关键环节进行详细分析;使用自制的细分电路板分别验证了以信号发生器和实际信号为输入的细分算法有效性,并且将改进数字锁相细分方法与传统锁相细分方法进行细分效果对比,实验结果证明,本文设计的数字锁相细分算法能够在更高的莫尔信号频率和频率变化率情况下完成细分功能,因而能够更好的应用于动态测量场合。     

莫尔条纹锁相细分误差补偿

<正> 一、绪言对于莫尔条纹的电子学细分、锁相技术的应用大约开始于六十年代初期。英国Goulder Mikron公司的齿轮单面啮合检查仪、齿距仪。苏联的БB—5058、БB—5059和БB—3244齿轮测量仪器等产品上均有锁相倍频技术的应用。我国成都工具研究所研制的单测头式齿轮整体误差测量仪及天津大学与天津第一机床厂研制的GYQ—80型光栅式齿轮误差检查仪,对光栅莫尔条纹的细分,也采用了锁相倍频技术。锁相倍频细分方法具有细分数高、对光栅     

非均匀采样莫尔条纹信号的分析与处理

为了动态、实时地测量光电编码器在变速转动情况下的细分误差,提出了一种莫尔条纹信号的非均匀采样分析与处理方法。利用傅里叶级数原理构造了实际情况下的莫尔条纹信号方程,根据编码器在不同转速下的实时采样,揭示了莫尔条纹信号的非均匀采样特征。鉴于信号采样的非均匀性,采用曲线拟合的最小二乘法重构莫尔条纹信号,利用离散傅里叶变换算法分析重构信号并求出波形参数。通过信号参数与细分误差的关系式,测量了编码器动态细分误差。采用该方法对21位绝对式光电编码器莫尔条纹信号进行了分析和处理,两次测试得到其动态细分极值误差为+3.21″、-4.69″和+3.45″、-4.81″。实验结果表明,该方法可以有效地分析和处理编码器在非匀速转动下产生的变频莫尔条纹信号,精确地测量编码器的动态细分误差,为工作现场编码器误差的实时检测与修正奠定了基础。     

空间精密位移信号软细分方法研究

为了解决高精度数控装备对位移传感器高分辨力反馈的需求,本文提出通过对空域信号特征的分析,从时空变换理论模型的角度去研究位移测量问题;利用光栅周期性栅线作为等空间位置触发位置采样建立空间序列模型;通过对光栅莫尔条纹信号自适应预测细分模型阶数与系数估计算法完成光栅莫尔条纹信号细分。实验结果证明此方法可以实现光栅莫尔条纹400倍细分,细分精度优于信号周期的±1%。此细分方法利用光栅刻划精度,信号细分精度与光栅信号波形质量无关,在不增加硬件的条件下实现光栅莫尔条纹精密细分,具有重要实际应用价值。     

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.     

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。     

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。     

交通荷载作用下桥梁结构参数识别方法

应用动力节点加载法,将作用在桥梁上的交通荷载转化为等效节点荷载,再用两步构造法识别结构物理参数.第1步,用Newmark-β方法变换结构运动方程,并用结构的加速度响应求得变换空间内的位移、速度和加速度响应;第2步,基于最小二乘原理,构造出变换空间内求解结构参数的递推式,进行结构物理参数识别.数值模拟结果表明,在交通荷载作用下,该方法能够快速、准确地进行桥梁结构参数识别.     

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。     

RLS and LMS blind adaptive multi-user detection method and comparison in acoustic communication

RLS and LMS blind adaptive multi-user detection algorithm and multi-user detector was proposed to solve the problem of multi-user signal detection problem encountered in underwater acoustic communication networks.In simulation analysis,RLS and the LMS blind adaptive multi-user detector were designed and tested for synchronous and asynchronous multi-user communication process.The results of SIR comparison and MMSE comparison show that,both of the two methods can realize blind adaptive detection when any user change in multi-user communication,during this process,the training communication sequences are not needed.The RLS algorithm has about 5 dB higher in SIR compared with LMS algorithm,and the convergence velocity of RLS algorithm is also higher than LMS algorithm when the communication users change.RLS algorithm has better ability in multi-user detection than that of LMS algorithm,and it has great attraction and guiding significance for solving the problem of multiple access interference(MAI) in multi-user communication.     

Robust Impedance Control of Robots Using an Adaptive Interaction Force Observer

For robot interaction control,the interaction force between the robot and the manipulated object or environment should be monitored.Impedance control is a type ...     

Research on key techniques of expendable conductivity temperature depth measuring system

This paper analysis the developing of expendable conductivity temperature depth measuring system(XCTD)and introduce its principle of measuring about temperature,salinity and depth of ocean.Some key techniques are put forward.According to the real needs of XCTD,conductivity sensor with high sensitivity is designed by principle of electromagnetic induce,the ocean conductivity from induced electromotive force has been calculated.Adding temperature correction circuit would help to reduce error of conductivity measurement because of sharply changing temperature.Advanced temperature measuring circuit of high precision and the constant current source is used to weaken effect of self-heating of resistance and fluctuation of the source.On respect of remote data transmission,LVDS is a good choice for the purpose of guarantee the quality of data transmitted and the transmission distance is reaching to thousand meters in the seawater.Modular programming method is also brought into this research aimed at improve the stability,reliability and maintainability of the whole measuring system.In February,2015,the trials in South China Sea demonstrate that the developed XCTD realize effective measurement at a speed of 6 knots and detection depth at 800 m.The consistency coefficient of the acquired data is greater than 0.99 and the success rate of probe launching is above 90%.     

CHARACTERISTCS OF FLUID FILM IN OPTIMIZED SPIRAL GROOVE MECHANICAL SEAL

In order to investigate the sealing performance variation resulted from the thermal deformation of the end faces, the equations to calculate the fluid film pressure distribution, the bearing force and the leakage rate are derived, for the fluid film both in parallel gap and in wedgy gap. The geometrical parameters of the sealing members are optimized by means of heat transfer analysis and complex method. The analysis results indicate that the shallow spiral grooves can generate hydrodynamic pressure while the rotating ring rotates and the bearing force of the fluid film in spiral groove end faces is much larger than that in the flat end faces. The deformation increases the bearing force of the fluid film in flat end faces, but it decreases the hydrodynamic pressure of the fluid film in spiral groove end faces. The gap dimensions which determine the characteristics of the fluid film is obtained by coupling analysis of the frictional heat and the thermal deformation in consideration of the equilibrium condition of the bearing force and the closing force. For different gap dimensions, the relationship between the closing force and the leakage rate is also investigated, based on which the leakage rate can be controlled by adjusting the closing force.