敏感器正常和故障模式下微小卫星的姿态确定方法

围绕某日-地空间环境组网探测系统中微小卫星定姿系统的设计需求,基于MEMS陀螺、小型CMOS太阳敏感器、微磁强计,研究了该微小卫星各敏感器正常工作模式以及敏感器故障模式下的系统建模和姿态确定方法。各敏感器正常工作模式下,用陀螺、太阳敏感器和磁强计进行组合定姿;陀螺故障时,用太阳敏感器和磁强计进行组合定姿;太阳敏感器故障时,用陀螺和磁强计进行组合定姿;陀螺/太阳敏感器同时故障时,用磁强计进行定姿。仿真结果表明,本文定姿方法的姿态确定精度满足该系统中微小卫星在轨运行时的定姿精度要求,为该微小卫星的半物理仿真系统的研究及其在轨运行时的姿态确定提供了依据。     

半球谐振陀螺星载惯性测量单元设计与实现

半球谐振陀螺是一种新型固体振动陀螺,具备功耗低、寿命长、稳定性高等特点,可完美适应卫星的姿态控制。针对微小卫星应用需求,利用半球谐振陀螺构建了星载惯性测量单元。首先,通过测量单元硬件结构设计,对其内部空间进行优化,并通过力学特性及力学试验仿真分析,验证其机械可靠性。其次,针对微小卫星应用环境优化半球谐振陀螺电路设计,提高惯性测量单元可靠性。最后,力学环境试验结果表明,三轴半球谐振陀螺的零偏稳定性均优于0.1°/h,敏感器件满足标度因数非线性度≤500ppm和零偏稳定性≤0.1°/h(1σ)的要求,实现了满足微小卫星应用需求的低成本、小体积、高可靠的半球谐振陀螺星载惯性测量单元。     

卫星三轴姿态确定系统的光纤陀螺/星敏感器组合技术研究

为了满足卫星三轴姿态确定的精度要求，提出了基于状态估计法的星敏感器和光纤陀螺组合的方案，并设计了相应姿态确定算法。通过仿真证明：此方案能达到高精度卫星姿态确定系统的要求。     

激光陀螺惯组系统级标定方法

针对激光陀螺惯性测量组件在传统的分立式标定中受橡胶减震器影响的问题,从系统的角度对激光陀螺惯性测量组件的标度因数误差、安装误差传播规律进行分析。通过分别绕三只陀螺敏感轴转动激发激光陀螺的标度因数误差、安装误差,通过三只加速度计敏感轴分别指天激发加速度计的标度因数误差、安装误差和零位,从而完成激光陀螺惯性测量组件的系统级标定。在未进行温控及温补的情况下,陀螺仪标度因数误差重复性在3.5×10~(-6)以内,安装误差重复性在3″以内,加速度计标度因数误差和零位在其性能指标内,安装误差在4.5″以内。试验结果表明,该方法满足高精度、长期稳定性好的惯导系统工程应用要求。     

基于半球谐振陀螺与星敏感器的星载姿态测量系统实现

为满足长寿命卫星对高精度、高可靠、低功耗、轻重量的姿态测量系统的需求,构建了一种基于半球谐振陀螺与星敏感器的星载姿态测量系统。针对国产半球谐振陀螺和加速度计结构特点,建立了惯性器件配置结构,完成了系统的相关标定,开发了以四元数为基础的姿态算法,利用卡尔曼滤波技术,将惯性姿态测量系统与星敏感器进行组合,实现了工程样机设计。测试表明,在实验室环境下,静态姿态精度达到13.9″(峰值),动态姿态精度达到15.4″(峰值),所研制的工程样机的精度指标能够满足高精度卫星的使用要求。     

光纤陀螺惯性测量单元的设计与实现

本文介绍采用全数字闭环光纤陀螺组成的惯性测量单元的实现方法,采用DSP作为中央处理单元,完成三轴组合的时序控制、数字解调、滤波算法、波形合成及数据传输,并对三轴陀螺进行了全面的性能测试,测试结果表明惯性测量单元中每个陀螺零漂均小于0.5°/h,标度因数线性度＜200 ppm,达到了预期的设计要求.     

MEMS-IMU构型设计及惯性器件安装误差标定方法

提出一种由三只单轴MEMS陀螺仪和三只单芯片双轴6个加速度计构成的MEMS-IMU配置方案。针对该方案的特点,研究了基于重力参考矢量对MEMS惯性器件安装误差的标定方法。该方法的关键是利用同一安装平面内的两个加速度计测量矢量的叉乘矢量的方向代替MEMS陀螺敏感轴方向,利用两轴或三轴角位置转台标定MEMS-IMU中惯性器件的安装误差。分析了标定矩阵的求逆条件数,提出了3位置和6位置的标定,指出了多位置标定中转台姿态角度的选择范围。新型MEMS-IMU配置方案及安装误差标定方法可有效解决MEMS-IMU惯性器件安装误差的标定与补偿问题。     

在飞航导弹中用星敏感器修正捷联惯导陀螺漂移

星敏感器是一种高精度的姿态测量装置。研究了星敏感器和陀螺的特点,对星敏感器工作原理和修正陀螺漂移技术进行了原理分析。在不利用外界提供的姿态和位置信息的情况下,采用卡尔曼滤波的信息融合算法,建立组合导航系统的状态方程和量测方程,利用星敏感器输出的载体相对于惯性空间的姿态信息来修正捷联惯导的陀螺漂移。设计飞航导弹的典型飞行轨迹,通过数学仿真,对上述算法的有效性进行了验证,结果表明星敏感器能够有效地补偿捷联惯导由于陀螺漂移带来的误差,明显提高了导航定位精度。     

模糊神经网络预测在卫星姿态测量中的应用

以满足对地观测卫星测姿精度为目标,将由惯性基准、红外地平仪和太阳敏感器测姿过程视为典型的建模问题,讨论了基于自适应神经网络的模糊推理系统(ANFIS)的卫星姿态预测。仿真结果表明,ANFIS预测能够满足卫星姿态测量精度的要求,具有较强的容错性,同时该方法可将俯仰、横滚和偏航三个姿态分离建模,有利于提高卫星姿态测量的可靠性,为卫星姿态测量信息处理提供了一种新的方法。     

弹载惯性/卫星/星光高精度组合导航

选取捷联惯导系统误差作为组合导航系统状态,利用捷联惯导与卫星导航系统各自的位置输出构造量测,设计惯性/卫星组合导航算法。在惯性/星光组合导航算法设计中,对星敏感器安装误差进行建模并也列入组合导航系统状态,利用星敏感器输出的姿态矩阵和根据惯导输出计算得到的等效姿态矩阵构造量测。从而,利用联邦滤波技术设计出弹载惯性/卫星/星光高精度组合导航方法。该组合导航方法的仿真结果表明,其定位、定姿精度分别达到12.1m(3σ)和0.27′(3σ),而且能够有效标定出惯性器件的随机常值误差和星敏感器的安装误差。     

The 7th International Conference on Fluid Mechanics May 24-27,2015,Qingdao,China

正http://www.icfm7.org First Announcement and Call for PapersThe objective of International Conference on Fluid Mechanics(ICFM)is to provide a forum for researchers to exchange new ideas and recent advances in the fields of theoretical,experimental,computational Fluid Mechanics as well as interdisciplinary subjects.It was successfully convened by the Chinese Society of Theoretical and Applied Mechanics(CSTAM)in Beijing(1987,     

INFORMATION FOR CONTRIBUTORS

Contributions： The Journal, Acta Mechanica Solida Sinica, is pleased to receive papers from engineers and scientists working in various aspects of solid mechanics. All contributions are subject to critical review prior to acceptance and publication.     

Preface

This special issue of PARTICUOLOGY is devoted to the first UK-China Particle Technology Forum taking place in Leeds, UK, on 1-3 April 2007. The forum was initiated by a number of UK and Chinese leading academics and organised by the University of Leeds in collaboration with Chinese Society of Particuology, Particle Technology Subject Group （PTSG） of the Institution of Chemical Engineers （IChemE）, Particle Characterisation Interest Group （PCIG） of the Royal Society of Chemistry （RSC） and International Fine Particle Research Institute （IFPRI）. The forum was supported financially by the Engineering and Physics Sciences Research Council （EPSRC） of United Kingdom,     

基于鲁棒滤波的捷联导引头视线角速度估计方法

针对捷联导引头无法直接获取视线角速度等信息的问题,研究了鲁棒滤波在大气层外飞行器捷联导引头视线角速度估计中的应用。为了建立非线性滤波估计模型,考虑目标视线角速度的慢变特性,采用一阶马尔科夫模型建立了状态方程;推导了视线角速度的解耦模型,并建立了量测方程;考虑到实际应用中存在系统噪声统计特性失准的问题,基于Huber-Based鲁棒滤波方法,设计了视线角速度滤波器,并完成了基于Huber-Based滤波方法和扩展卡尔曼滤波方法的数学仿真。仿真结果表明Huber-Based滤波方法的视线角、视线角速度及视线角加速度估计精度分别达到0.1140'、0.1423'/s、0.0203'/s2,而扩展卡尔曼滤波方法的视线角、视线角速度及视线角加速度估计精度仅分别为0.6577'、0.6415'/s、0.0979'/s~2。仿真结果证明了该方法可以有效地估计出相对视线角速度等信息,并且在非高斯噪声的条件下,依然可获得较高的估计精度,具有一定的鲁棒性。     

Guide for authors

正Each of the sections below provides essential information for authors.We recommend that you take the time to read them before submitting a contribution to Acta Mechanica Sinica.We hope our guide to authors may help you navigate to the appropriate section.How to prepare a submission This document provides an outline of the editorial process involved in publishing a scientific paper in Acta Mechanica     

Use specification of multiscale materials for life spanned over macro-, micro-, nano-, and pico-scale

Multiscale material intends to enhance the strength and life of mechanical systems by matching the transmitted spatiotemporal energy distribution to the constituents at the different scale, say—macro, micro, nano, and pico,—, depending on the needs. Lower scale entities are, particularly, critical to small size systems. Large structures are less sensitive to microscopic effects. Scale shifting laws will be developed for relating test data from nano-, micro-, and macro-specimens. The benefit of reinforcement at the lower scale constituents needs to be justified at the macroscopic scale. Filling the void and space in regions of high energy density is considered.Material inhomogeneity interacts with specimen size. Their combined effect is non-equilibrium. Energy exchange between the environment and specimen becomes increasingly more significant as the specimen size is reduced. Perturbation of the operational conditions can further aggravate the situation. Scale transitional functions and/or f_j/j+1 are introduced to quantify these characteristics. They are represented, respectively, by , and (f_mi/ma,f_na/mi,f_pi/na). The abbreviations pi, na, mi, and ma refer to pico, nano, micro and macro.Local damage is assumed to initiate at a small scale, grows to a larger scale, and terminate at an even larger scale. The mechanism of energy absorption and dissipation will be introduced to develop a consistent book keeping system. Compaction of mass density for constituents of size 10⁻¹², 10⁻⁹, 10⁻⁶, 10⁻³ m, will be considered. Energy dissipation at all scales must be accounted for. Dissipations at the smaller scale must not only be included but they must abide by the same physical and mathematical interpretation, in order to avoid inconsistencies when making connections with those at the larger scale where dissipations are eminent.Three fundamental Problems I, II, and III are stated. They correspond to the commonly used service conditions. Reference is made to a Representative Tip (RT), the location where energy absorption and dissipation takes place. The RT can be a crack tip or a particle. At the larger size scales, RT can refer to a region. Scale shifting of results from the very small to the very large is needed to identify the benefit of using multiscale materials.