无人机磁惯导系统中陀螺仪的叉积标定算法*

针对无人机磁惯导系统(MINS)中的三轴MEMS陀螺仪的现场标定问题,提出了一种叉积标定算法。该方法基于载体矢量变化率与角速度关系来标定陀螺仪的各项误差,即导航坐标系中任一常矢量在无人机载体坐标系中对时间的变化率,可表示为该矢量与载体角速度的叉积。叉积标定法利用这一原理,可在无精密设备的条件下快速、便捷地对三轴陀螺仪进行标定。数值仿真表明,叉积标定法在微分形式和积分形式下都能有效地辨识和补偿陀螺仪的各项误差系数,并且能在各种不同因素影响下获得良好的标定效果。实物试验结果证明,基于地磁矢量辅助的叉积标定法对MINS模块中陀螺仪进行标定时,其精度达到0.227 9°/s,能够接近于转台标定的水平。陀螺仪标定后的数据与旋翼无人机飞控中的二阶互补滤波算法相结合,使得定点悬停状态下角度偏差控制在0.8°以内,有利于无人机现场标定和实际飞行中姿态数据的量测。     

基于两步修正法的 MEMS 三轴陀螺仪标定方法

针对目前三轴陀螺仪标定存在依赖于昂贵的转台设备或标定参数不完全的问题,本文提出了一种了基于两步修正法的MEMS三轴陀螺仪标定方法。该方法首先使用六位置法对加速度计12参数模型、三轴陀螺仪比例因子、三轴陀螺仪静态零偏进行标定补偿,然后对三轴陀螺仪非正交误差模型建模,进行系统级标定。两步修正法可实现在无精密设备条件下快速准确的对各项误差进行辨识,获得良好的标定效果。仿真实验表明,本文算法所获得的非正交误差均值接近1%,标准差小于0.1%;比例因子误差均值小于0.14%,标准差小于0.004%,且具有很好的一致性。实际实验表明,65 s纯惯性导航姿态更新结果中,该标定方法的俯仰角误差精度可以达到0.624°,横滚角误差精度可以达到0.67°。     

面向机器人遥操作的数据手套设计及仿真验证

针对面向机器人遥操作的数据手套精度低、成本高以及惯性测量单元校正难、校正不完全等问题,基于9轴惯性测量单元设计了一款数据手套,对传感器数据进行了校正、融合,并在Simulink中搭建了仿真系统。采用LM算法校正加速度计和陀螺仪数据,椭球拟合算法校正磁力计数据;采用扩展卡尔曼滤波算法融合校正后的9轴数据,得到传感器的实时姿态。实验结果表明：经校正、融合得到的传感器三轴动态角度,其均方根误差小于1.5°,最大误差绝对值小于3°,计算得到的手指关节静态角度误差小于1°。该数据手套系统可以较准确地检测手指的姿态,并能实时控制虚拟灵巧手的运动,同时也能获得手指关节运动的角度、角速度等信息。     

基于椭球拟合的三轴磁传感器快速标定补偿方法

考虑到现有多轴磁传感器的标定补偿方法中普遍存在操作时间长、计算量较大、标定设备要求高、场地要求面积大等问题,提出一种基于椭球拟合的三轴磁传感器误差标定补偿方法。首先,分析传感器误差产生机理,并在此基础上,建立传感器误差模型,推导出各误差系数的计算公式,并利用椭球拟合的方法对三轴磁传感器进行测试标定与误差补偿。实验结果表明,该方法能够正确、有效地标定补偿三轴磁传感器的不正交误差、灵敏度误差以及零偏误差,具有操作简捷、省时、精度高等特点。     

一种新的基于加速度计的无陀螺捷联惯性导航系统设计与实现

提高角速度解算精度是提高无陀螺惯性导航系统导航参数解算精度的主要途径.本文通过对基于加速度计的无陀螺惯性导航系统的基本方程进行分解分析,研究了提高角速度解算精度的所有可能的加速度计安装布局方案,并结合考虑各种可能方案的原理样机的机械加工难易程度后,设计确定了一种新的既能够提高角速度解算精度、又易于实现样机研制的9加速度计的设计安装方案,根据该方案研制了样机,编制了导航参数解算软件,对系统进行了实验测试,实验结果表明,在静态条件下,研制的无陀螺惯性导航系统1 h的位置误差精度达到了1.5 km,姿态解算精度达到了0.082°.     

6UPS并联机构铰链间隙误差的标定与精度分析

研究了常用的机构标定方法及相应的测量工具,使用激光干涉仪完成了测量实验,并使用矢量法误差求解模型对测量结果进行了分析计算,获得了机构静平台铰链的安装位置误差、杆长的误差变化、动平台铰链的位置误差数值,并提出了采用拟合误差椭球面的方法对铰链位置装配误差与铰链间隙误差进行分离的误差分析方法,研究了椭球的求解方法,得到了椭球的长轴、次长轴和短轴参数,进一步比较了所有铰链误差在坐标系中的空间分布情况,研究了机构安装结构和铰链类型与误差分布规律的相互关系,这样优化的误差数据可以取得比较好的补偿效果。     

双轴地磁传感器的参数标定与误差补偿

针对在双轴地磁传感器与卫星组合测量弹丸姿态的系统中双轴地磁传感器容易受外界误差因子干扰的问题,通过分析影响地磁传感器测量精度的误差因子,提出了一种参数标定和基于椭圆旋转的误差补偿算法。首先,假设双轴地磁传感器存在虚拟x轴,对传感器的误差因子进行建模,得到误差补偿模型;其次,对传感器双轴输出表达式中的参数进行标定;对双轴的测量值集合形成的椭圆进行旋转;最后,计算误差补偿模型中的6个参数。三轴无磁转台实验数据分析表明,该方法可以将双轴地磁传感器测量滚转角的误差精度控制在±2°之间,基本满足了弹丸姿态测量的要求。     

巡飞弹空中自适应快速初始姿态估计

为了解决巡飞弹空中上电后在无参考姿态条件下的初始姿态确定问题,采用低成本磁力计、陀螺仪和加速度计(MARG)传感器设计姿态航向参考系统(AHRS),并提出了一种自适应参考矢量权重的快速初始姿态估计(AFCF)算法。首先,提出了三轴传感器使用前的快速误差校准方法;然后,采用快速互补滤波算法进行姿态估计,分析了其权重函数对于初始姿态估计及收敛性等的影响;接着,提出自适应参考矢量权重及自适应姿态估计方法;最后,利用高精度MTI(Milliren Technologies,Inc)传感器数据对算法进行了验证,并在低成本MARG姿态航向参考系统中对算法进行了实现,对比了改进算法及扩展卡尔曼滤波(EKF)算法的性能。实验结果与分析表明:动态条件下采用MTI传感器数据,改进算法能够在初始时刻收敛,比快速互补滤波(FCF)算法提前约4s;解算精度约为±0.6°,初始时刻精度明显优于FCF;硬件测试则表明改进算法的处理时间为0.062ms,仅为EKF算法的1/9,解算精度约为±1.3°,能够满足姿态测量过程快速收敛、高精度、实时性等要求。     

一种改进的挠性陀螺POS标度因数误差补偿方法

针对航空遥感的作业环境特点,分析了一类位置姿态测量系统(position and orientation system,POS)用挠性陀螺的标度因数与输入角速度之间的关系.通过实验发现了在小角速率范围内陀螺标度因数与输入角速度呈规律性的“双曲线”关系.提出了一种改进的多位置动静混合误差标定与补偿方法.首先根据输入角速度的正负分别标定陀螺标度因数并建立两者的对应关系,然后在误差补偿时根据输入角速度的方向和数值变化更新标度因数及其他误差系数,进而提高误差补偿精度.实验结果表明,利用改进方法进行误差补偿后POS角测量精度可以提升约20％.     

一种新型的矿井井斜测量方法研究

井斜测量单元研究是基于捷联惯性导航原理,由三轴光纤陀螺和三轴加速度计构成惯性测量单元,通过数学平台实时地解算出载体的姿态角、位置和速度等参数.以煤矿勘测和开采为背景,采用捷联惯性导航系统替代传统的平台惯性导航系统,利用光纤陀螺和加速度计构成惯性敏感单元替代传统的磁通门和加速度计的结构,适用于具有磁场干扰的场合.初步完成井斜测量系统的静态测试,并对产生的测量误差进行了分析,姿态角可获得较高的测量精度,基本满足井斜测量的指标.利用Labview进行数据采集界面和姿态信息显示界面设计,具有良好的交互性和实时性的特点.     

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.     

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。     

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....     

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.     

Limits of topographic measurement by the scanning tunnelling and atomic force microscopes

Parameters describing the topographic character of a surface (height, surface wavelength, slope and curvature) can be derived from equivalent sinusoidal profiles. The response of a surface-measuring instrument may be modelled in terms of instrument parameters such as stylus radius, and scanning range and resolution. The performance of the instrument may then be mapped as a zone in amplitude-wavelength (AW) space to show the sinusoidal profiles it is capable of measuring. In a first-order analysis the STM and AFM are considered as equivalent to contact-stylus instruments with a notional stylus radius equal to the tip radius plus the gap. Comparisons between different instruments and types of instrument are readily made by mapping in AW space. The error arising from convolution of the sinusoidal profile with that of the finite tip may be quantified and plotted as contours in AW space.