高超声速飞行器机体／发动机耦合建模与控制

为了真实的反映高超声速飞行器机体、发动机间的耦合特性,首先建立了超燃冲压发 动机预压缩面、进气道、燃烧室、尾喷管、外喷管的数学模型,推导了以敏感度方程表示的 机体对发动机的耦合模型和发动机对机体的耦合模型,然后建立了飞行器点火飞行段的数学 模型,并进行了简单的校核,最后基于变结构控制理论设计了一种简单的开环＋闭环的控制 系统。模型的简单校核及控制系统仿真表明建立的模型定性上符合高超声速点火飞行段的飞 行特性,设计的控制器在存在干扰、噪声、拉偏时能够快速收敛,且鲁棒性强。     

空间平台下传递对准方案

提出了惯性坐标系下空间平台主惯导与有效载荷子惯导之间的传递对准方案。首先, 介绍了惯性坐标下捷联惯导系统算法及其流程图。然后,推导了惯性坐标系下的传递对准状 态方程,包括捷联惯导系统误差方程以及姿态失准角模型方程;推导了传递对准姿态匹配量 测方程。最后,给出了传递对准最优状态方程和降阶状态方程,并且讨论了仿真流程和仿真 环境;传递对准仿真结果表明在10s时间内,在给定的机条件下,子惯导与主惯导的失准角估计精度在1′以内。     

基于多轴同步控制的微尺度双向加载实验系统

针对目前微细成形中材料屈服、强化行为实验研究的不足,提出通过建立多轴同步控制的微尺度双向加载实验系统,实现超薄板在复杂加载路径下的性能表征测试。双向加载实验系统基于四轴独立驱动的硬件组成和上、下位机分布式控制策略,采用数字散斑测量（DIC）计算实验过程的应变。通过建立交流永磁同步电机（PMSM）控制模型,辨识了速度闭环控制参数。在非线性PID控制方法实现单轴位置闭环控制的基础上,基于虚拟主轴法实现了不同位移/载荷比例条件下的四轴同步运动。双向加载实验结果表明:同步控制精度满足位移小于等于0.02 mm、载荷小于等于0.05 kN的要求,可用于超薄板微尺度屈服和强化行为的实验研究。      

CME引起的地磁暴穿越时间

日冕物质抛射(CME)从发生至引起地磁暴最大值的时间间隔称为穿越时间.本文选取1997-2015年89个CME-Dst事件,分析CME速度、能量、耀斑类型等对穿越时间的影响;采用非线性拟合以及支持向量机(SVM)非线性回归技术,建立基于1997-2009年62个CME-Dst事件的CF模型和SVM模型,并利用其余27个CME-Dst事件对模型预报效果分别进行检验.结果表明,CF模型和SVM模型的预报准确率均达到85.2%,其中CF模型的平均绝对值误差为13.77 h,而SVM模型为13.88 h.与ECA模型结果(准确率为77.8%,平均绝对值误差为14.55 h)进行对比发现,CF模型和SVM模型的准确率更高而误差更小.CF模型和SVM模型能够提前1~5天较好地预报地磁暴爆发时间.     

LXI总线技术在测量领域中的应用研究

介绍了总线发展趋势及LXI总线出现的背景,分析了LXI总线的特点及其优势。从硬件构成和软件构成两方面对分布式测试系统进行了设计,最后以变电站分布式测试系统设计为例讲解了LXI技术在测试测量领域中的应用。     

Investigation of straightforward impedance eduction method on single-degree-of-freedom acoustic liners

In order to address the current aircraft noise problem, the knowledge of impedance of acoustic liners subjected to high-intensity sound and grazing flow is of crucial importance to the design of high-efficiency acoustic nacelles. To this end, the present study is twofold. Firstly, the StraightForward impedance eduction Method (SFM) is evaluated by the strategy that the impedance of a liner specimen is firstly experimentally educed on a flow duct using the SFM, and then its accuracy is checked by comparing the numerical prediction with the measured wall sound pressure of the flow duct. Secondly, the effects of grazing flow and high-intensity sound on the impedance behavior of two single-layer liners are investigated based on comparisons between educed impedance and predictions by three impedance models. The performance of the SFM is validated by showing that the educed impedance leads to excellent agreement between the simulation and the measured wall sound pressure for different grazing flow Mach numbers and Sound Pressure Levels (SPLs) and over a frequency range from 3000?Hz down to 500?Hz. The grazing flow effect generally has the tendency that the acoustic resistance exhibits a slight decrease before it increases linearly with an increase in Mach, predicted successfully by the sound-vortex interaction theoretical model and the Kooi semi-empirical impedance model. However, the Goodrich semi-empirical impedance model gives only a simple linear relation of acoustic resistance starting from Mach zero. Additionally, when the SPL increases from 110 to 140?dB in the present investigation, the acoustic resistance exhibits a significant increase at all frequencies in the absence of flow; however, the resistance decreases slightly under a grazing flow of Mach 0.117. It indicates that the SPL effect can be greatly inhibited when flow is present, and the grazing flow effect can be reduced partly as well at a relatively high SPL.     

Materials Experiment on Tiangong-2 Space Laboratory

During the China's Tiangong-2 (TG-2) flight mission, the experiments of 18 kinds of material samples were conducted in space by using a Multiple Materials Processing Furnace (MMPF) mounted in the orbital module of the TG-2 space laboratory. After the experiments of 12 kinds of samples of the first and second batches were completed successfully, astronauts packed and brought them back to the ground by ShenzhouⅡ spacecraft. By studying processing and formation on semiconductor and optoelectronics materials, metal alloys and metastable materials, functional single-crystal, micro-and nano-composite materials encapsulated in sample ampoules both in space and on Earth, we expect to explore some physical and chemical processes and mechanism of the materials formation that are normally obscured and therefore are difficult to study quantitatively on the ground due to the gravity-induced convection, to obtain the processing and synthesis technology for preparing high quality materials, and lead to the improvement and development of materials processing techniques on Earth, and also develop the experiment device and comprehensive ability for materials experiment in microgravity environment. This report briefly introduces the main points of each research work and preliminary comparative analysis results of 12 samples carried out by scientists undertaking research task.      

客车铝合金车架设计与典型工况分析

应用轻量化材料如高强度钢和铝、镁合金等来替代普通钢制造汽车承载构件已成为发展趋势。本文以工业铝合金为材料设计了一种新型的轻型城郊客车车架,并建立有限元模型进行了多种典型工况的仿真分析。首先,基于CATIA进行了客车车架各零部件的设计,整体装配与校核;然后,通过简化模型、模拟连接等,在ANSYS Workbench中建立了合理的车架-悬架有限元模型;最后,模拟客车满载弯曲、制动等5种典型工况施加载荷与边界条件,进行有限元仿真,仿真结果表明该铝合金车架能够满足各典型工况的强度和刚度性能要求。      

大迎角分离流场在等离子体控制下的特性研究

设计了一种新型的大迎角主动流动控制方法.采用圆锥-圆柱组合体模拟飞行器前体,在靠近圆锥尖端处镶嵌了一对马蹄形单电极介质阻挡放电(Single-Dielectric Barrier Discharge SDBD)等离子体激励器,通过风洞实验研究了等离子体激励器在不同状态下对大迎角模型前体的非对称气动载荷的控制作用.实验结果表明,通过控制等离子体激励器的开闭可以使得圆锥-圆柱组合体在大迎角下出现的侧力改变方向.还对通过调节单侧等离子体激励器的激励电压实现圆锥前体侧力系数在正负极值间连续变化的可能性进行了初步的实验探索.     

火箭发动机燃烧过程无记忆鲁棒镇定的积分不等式方法

研究了液体火箭发动机燃烧室燃烧过程的无记忆鲁棒镇定问题。通过构造适当的Lyapunov泛函并结合积分不等式变换技巧,将所得的非线性矩阵不等式转化为可解的线性矩阵不等式,导出了不确定时滞系统可鲁棒镇定的时滞相关条件。与现有方法相比,该方法不涉及模型变换技术,因而减少了理论与计算上的复杂性。同时在较大的参数变化范围内保证了燃烧过程的鲁棒镇定。最后通过数值仿真验证了其有效性。