超荧光光源温度动态特性的分析及控制

针对高精度光纤陀螺对光源稳定性的需求,提出了一种以32位数字信号处理器TMS320F2812为核心的掺铒超荧光光纤光源(SFS)的数字化温控方案。以该光纤光源(SFS)为研究对象,分析了现有的光源温度控制技术的优缺点;在模拟控制方案的基础上,提出了"数字恒流源+数字温控"的方案。研究了热电制冷器(TEC)的工作特性、SFS泵浦源的内部结构和传热机理,建立了SFS光源管芯温控系统的数学模型。设计了相应的连续域超前-滞后校正网络,并进行控制器的离散化处理,得到了PID数字补偿控制算法。最后,实验验证了SFS光源的数字化温控系统的温控精度。结果表明,在20~90℃,系统温控精度优于±0.05℃,满足了光纤陀螺低功耗、小型化等要求。     

三轴一体化光纤陀螺光源驱动技术

根据三轴一体化光纤陀螺共享光源,要求光源能够提供较大的高精度的恒流以满足实际需要.结合SLD(超辐射发光二极管)光源结构特点及其工作原理,采用恒流和温控方案,设计了新的高精度恒流驱动和温度控制系统.经测试结果表明,设计的系统能够在环境温度为-45℃～ 70℃内稳定工作,实现了高精度恒流和温度驱动控制,满足三轴一体化光纤陀螺对光源驱动的要求.     

光纤陀螺用SLD光源的光功率稳定性研究

SLD光源的稳定性对光纤陀螺的性能有及其重要的影响。为提高光纤陀螺的精度 ,设计了 SLD光源的数字化控制系统 ,采用“恒流 +温控”的方案 ,并引入了数字 PID控制算法 ,大大提高了光源出纤光功率的稳定性。用实验证明了数字方法的控制效果远远好于目前广泛应用的模拟控制方法     

光纤陀螺用SLD光源的控制方法研究

光源控制技术是光纤陀螺技术研究领域的关键技术之一.为进一步提高光源的控制精度,从SLD光源驱动原理出发,提出光源模拟控制与数字控制方案,分析了电路原理,结合实际研究情况,从恒流精度、温控精度及光功率等关键技术指标出发,对两种方案进行比较并给出结论.     

自主式光纤陀螺油井测斜仪

简要介绍了光纤陀螺原理，分析了光纤陀螺应用于油井测斜的优点。研制了基于惯性测量技术的光纤陀螺测斜仪，它是一种不依赖任何外部设备，完全自主且实时快速的井眼轨迹测量仪器。样机实验结果表明：该仪器能够实现全方位测量，满足石油测井要求。     

基于内模的光纤陀螺温控系统设计

本文针对光纤陀螺对温度敏感这一特性,在充分分析光纤陀螺物理特性基础上,分析了温度对陀螺噪声、陀螺光源的影响,温度的变化将导致光线环中不同区段上光纤的折射率不同,这种不同将最终导致光纤陀螺的零点随温度的变化而发生漂移;随后建立了相应的温度误差模型;通过最小二乘拟合,建立了较为准确的控制对象模型,采用内模控制方法对温控系统进行了设计,其设计原理简单、跟踪调节性能好、鲁棒性强、参数整定直观明了,能消除不可测干扰的影响;最后通过系统仿真,对分别用内模控制和常规PID控制设计的温控系统进行了比较,通过比较分析,验证了内模控制对于本系统所具有的优越性,研究成果对设计高精度温度控制系统有着重要的参考价值。     

光纤陀螺用SLD光源全数字控制系统

超辐射发光二极管(SLD)是干涉式光纤陀螺的理想光源,介绍了全数字SLD光源控制系统的硬件构成、控制软件流程及PID算法。测试结果表明,在-20～50℃温度范围内,光功率波动小于0.3%,平均波长的温度漂移为3×10-6/K,此数控方法在光纤陀螺高精度、工程化研究中有良好的应用前景,对其他半导体激光光源的高精度控制具有通用性。     

光纤陀螺用SLD的光功率自动控制的实验研究

光纤陀螺(FOG)所用光源的特性对光纤陀螺的性能有很大的影响,着重介绍半导体光源超辐射二极管(SLD)的特性,以及SLD的稳定性对光纤陀螺的影响。针对环境温度和驱动电流对SLD光功率稳定性的影响,设计光功率控制方案及相应的驱动控制电路。     

基于SoC单片机的小型化SLD光源数字控制系统设计

为提高光纤陀螺用超辐射发光二极管(SLD)光源的稳定性,实现光源性能检测和评价的灵活性,在光源工程化生产中常采用数字化控制系统对光源进行控制。以SoC单片机C8051F060为控制检测平台,结合高性能TEC控制器ADN8831和数字PID控制算法,设计了新型小型化光源数字控制系统。实验表明,该光源数字化控制系统体积小,精度高,操作灵活,可扩展性强,具有良好的实用价值。     

用于高精度光纤陀螺的掺铒光纤宽带光源的优化

为优化双程后向结构的掺铒光源,分析了光纤长度、泵浦功率和温度的变化对光源平均中心波长的影响,初步确定了掺铒光纤长度的优化范围,并在全温度范围内进行实验验证。实验选用的980nm泵浦源电流为110mA,掺铒光纤的长度为12.5m,该装置的输出功率为13.26mW,光源的平均波长稳定性为0.6℃-1。通过建立光谱分布优化仿真模型,实现输出光谱的近高斯分布,3dB带宽达到32nm。经过优化后得到的掺铒光纤光源具有输出功率高、平均波长稳定性好、输出光谱呈高斯分布等优势,是高精度光纤陀螺的理想光源。     

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...     

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.     

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.     

Application of Feature Extraction through Convolution Neural Networks and SVM Classifier for Robust Grading of Apples

This paper proposes a novel grading method of apples,in an automated grading device that uses convolutional neural networks to extract the size,color,texture,an...     

分布动态载荷识别的抗噪处理

针对正交多项式频域法在用多种响应对矩形薄板进行载荷识别中抗噪性较差的问题,综合运用平均法、矩阵预处理和奇异值截断法等方法对之进行改善,并引入空间映射的思想,将该方法的应用范围拓展为复杂的模型.利用仿真算例,证实了该方法具有较好的抗噪性.     

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....     

基于MELTAC-N平台的核电厂安全级DCS环网研究与测试

针对工程实践中环网通讯相关问题的处理缺乏理论基础及国产化安全级DCS平台的开发缺乏成熟经验借鉴问题,对基于MELTAC-N平台核电厂安全级DCS环网的软硬件实现进行了研究。提出了安全级DCS环网双环网冗余设计、光切换开关设计等硬件设计方法,以及以RPR协议为基础,采用全数据收发策略的软件设计方法。在CPR1000安全级DCS平台上对安全级DCS环网的可靠性及实时性进行了评价,并进行了容错能力、响应时间及响应时间稳定性测试验证实验。结果表明,基于MELTAC-N平台安全级DCS环网软硬件设计具有较好的容错能力及响应时间稳定性。     

The laboratory simulation of abrasive wear

Abrasive wear has long been recognised as one of the most potentially serious tribological problems facing the operators of many types of plant and machinery; several industrial surveys have indicated that wear by abrasion can be responsible for more than 50% of unscheduled machine and plant stoppages. Locating the operating point of a tribological contact in an appropriate operational ‚map’︁ can provide a useful guide to the likely nature and origins of the surface degradation experienced in use, though care must be exercised in choosing the most suitable parameters for the axes of the plot. Laboratory testing of materials and simulations of machine contacts are carried out for a number of purposes; at one level for the very practical aims of ranking candidate materials or surface hardening treatments in order of their wear resistance, or in an attempt to predict wear lives under field conditions. More fundamentally, tests may be aimed at elucidating the essential physical mechanisms of surface damage and loss, with the longer term aim of building an analytical and predictive model of the wear process itself. In many cases, component surface damage is brought about by the ingress of hard, particulate matter into machine bearing or sealing clearances. These may be running dry although, more usually, a lubricant or service fluid is present at the interface. A number of standardised wear test geometries and procedures have been established for both two- and three-body wear situations, and these are briefly described. Although abrasive wear is often modelled as following an ‚Archard’︁ equation (i.e. a linear increase in material loss with both load and time, and an inverse dependence on specimen hardness) both industrial experience and laboratory tests of particularly lubricated contacts show that this is not always the case: increasing the hardness differential in an abrasively contaminated lubricated pair may not always reduce the rate of damage to the harder surface.     

ANGULAR DISTORTION ALLOWABLE VALUE AND ASSESS METHOD OF WELD ON COKE TOWER

A graph as the new engineering method for estimate the safety of bulging deformation of coke tower is proposed. Through stresses analysis of circumferential weld of coke tower and comparing the stresses produced by pressure with heat stress of steady state, residual stress, bending stress produced by both itself weight and wind loads, it showed that the stresses produced by pressure on the angle distortion are the main factor of equivalent stress of the combined stress. After comparing four kinds of stress controlling conditions, the relation to stress with depth of angular distortion, grade of curvature of angular distortion and half of region of angular distortion has been inferred. Graph of deformation allowable value of coke tower for different condition by angular distortion and half of region of angular distortion has been plotted. The five steps for its engineering use have been explained. The lighter the grade of curvature is, the larger of bulge allowance, may be, and the bigger of depth of angular distortion may pose too. For the coke tower with a popular structure of Dg 5 400 mm×28 mm, the result by graph is nearly more than the result of two formulas formed by other research, the error is less than 7.0%. But, the graph can be easily applied to different size of angular distortion.