脉冲激光诱发130 nm体硅CMOS器件的单粒子闩锁效应

基于130nm体硅CMOS工艺,设计了具有不同阱/衬底接触与MOS管有源区间距、NMOS有源区与PMOS有源区间距的反相器链,利用脉冲激光试验开展了不同设计和不同工作电压下CMOS电路的单粒子闩锁效应敏感性研究.结果表明,随着阱/衬底接触与MOS管有源区的间距减小,以及NMOS与PMOS有源区间距的增大,电路抗SEL效...     

基于BiSNet的航天发动机转子智能健康监控

航天发动机某部件转子健康监控,对检测发动机能否正常工作进而影响航天发射任务的成败至关重要.传统健康监控方法需要依赖经验和专业知识,在对故障机理深入理解后才能构建相应的健康监控模型.针对传统转子健康监控手段效率低、适应性差、过度依赖专家经验等不足,结合海量转子振动健康监控历史数据,提出并设计采用神经网络BiSNet的人工...     

固体姿轨控发动机动态推力补偿

作为实现导弹快速机动响应的关键部件,固体姿轨控发动机的性能需要通过动态多分力测试评价,但由于推力测试台结构复杂,对测试数据补偿提出了更高的要求。本文采用双模态阻尼补偿法开展固体姿轨控发动机推力补偿研究,通过脉冲激励试验获得了主要模态参数,并对脉冲激励和发动机冷流试验数据进行补偿,验证了双模态阻尼补偿方法的可行性和应用效果。结果表明:双模态阻尼补偿效果优于单模态补偿,可以有效恢复动态推力信号。所建立的双模态阻尼补偿,在姿轨控发动机研制中得到了应用。     

基于深层循环神经网络的陀螺仪降噪方法研究

陀螺仪固有的随机误差会随时间积累越来越大，循环神经网络作为一种有效处理时间序列信号的算法被广泛使用，然而传统的循环神经网络在处理陀螺仪产生的随机误差上无法解决长期依赖，容易出现梯度消失和梯度爆炸问题.为了获得精确的陀螺仪信号，本文基于循环神经网络变体的长短记忆网络和门循环单元的陀螺仪信号降噪算法，并创新性的将两种网络进行组合验证.文中先是通过Allan方差对陀螺仪随机误差进行误差分析，然后基于LSTM和GRU组合对陀螺仪输出信号进行补偿处理，结果表明LSTM结合GRU对陀螺仪的随机误差处理有明显改善，其中X、Y、Z轴方向陀螺仪的量化噪音、角度随机游走、零偏不稳定性、角速度游走和速度斜坡性能均有不同程度的提升.     

Influence of thermal inhibitor position and temperature on vortex-shedding-driven pressure oscillations

Vortex-acoustic coupling is one of the most important potential sources of combustion instability in solid rocket motors (SRMs). Based on the Von Karman Institute for Fluid Dynamics (VKI) experimental motor, the influence of the thermal inhibitor position and temperature on vortex-shedding-driven pressure oscillations is numerically studied via the large eddy simulation (LES) method. The simulation results demonstrate that vortex shedding is a periodic process and its accurate frequency can be numerically obtained. Acoustic modes could be easily excited by vortex shedding. The vortex shedding frequency and second acoustic frequency dominate the pressure oscillation characteristics in the chamber. Thermal inhibitor position and gas temperature have little effect on vortex shedding frequency, but have great impact on pressure oscillation amplitude. Pressure amplitude is much higher when the thermal inhibitor locates at the acoustic velocity anti-nodes. The farther the thermal inhibitor is to the nozzle head, the more vortex energy would be dissipated by the turbulence. Therefore, the vortex shedding amplitude at the second acoustic velocity antinode near 3/4L (L is chamber length) is larger than those of others. Besides, the natural acoustic frequencies increase with the gas temperature. As the vortex shedding frequency departs from the natural acoustic frequency, the vortex-acoustic feedback loop is decoupled. Consequently, both the vortex shedding and acoustic amplitudes decrease rapidly.     

Infrared radiation signature of exhaust plume from solid propellants with different energy characteristics

The infrared radiation signature of the plume from solid propellants with different energy characteristics is not the same. Three kinds of double-base propellants of different energy characteristics are chosen to measure the infrared spectral radiance from 1000 cm 1 to 4500 cm 1 of their plumes. The radiative spectrum is obtained in the tests. The experimental results indicate that the infrared radiation of the plume is determined by the energy characteristics of the propellant. The radiative transfer calculation models of the exhaust plume for the solid propellants are established. By including the chemical reaction source term and the radiation source term into the energy equation, the plume field and the radiative transfer are solved in a coupled way. The calculated results are consistent with the experimental data, so the reliability of the models is confirmed. The temperature distribution and the extent of the afterburning of the plume are distinct for the propellants of different energy characteristics, therefore the plume radiation varies for different propellants. The temperature of the fluid cell in the plume will increase or decrease to some extent by the influence of the radiation term.     

侵彻制导武器终端多约束最优制导律

针对侵彻型制导武器终端多约束制导问题,建立包含一阶弹体动力学的多约束制导模型,采用最优控制方法推导终端多约束制导问题的通解。根据终端约束与罚函数的关系,求解了实际工程中关心的3种最优制导律,并结合当前主流制导控制体制,在小角假设下,将其表述为便于工程实现的形式,即包含弹体动力学的最优比例导引制导律、弹道成型最优制导律和终端多约束最优制导律。理论分析和典型末制导条件仿真表明,后2种制导律可为侵彻制导武器终端位置与角度双约束以及位置、角度与加速度多约束制导问题提供理论基础和工程应用参考。     

基于数据挖掘算法的热压罐固化周期预测研究

目前,计划人员只能根据相关工艺文件中固化参数及热压罐固化周期的历史数据对热压罐进行连续排罐,导致计划人员无法制定精细的排产计划,还没有利用数据挖掘算法对热压罐固化周期进行预测的研究。采用支持向量回归和KNN预测两种预测方法,并对两种方法的预测结果进行对比试验。试验表明KNN预测的预测结果中有90%的罐次均优于支持向量回归的预测结果,且有90%罐次的误差小于0.5h。最后对两种方法的预测结果进行了原因分析。     

基于蒙皮内形定位的飞机壁板柔性装配系统

针对飞机壁板数字化、柔性化制造需求,提出一种基于蒙皮内形定位的飞机壁板柔性装配方法,通过有限元参数化建模,应用蒙皮支撑点寻优算法,实现卡板布局优化设计.根据壁板组件各零件的定位要求,详细设计了壁板柔性装配系统中长桁、蒙皮、角片的柔性定位方式,开发了基于EtherCAT总线的分布式网络控制系统用于完成整个壁板的装配.本系...     

低雷诺数下横流-射流中剪切涡的试验研究

为深入分析横流-射流(JICF)的流动特性及其中的复杂涡系结构,从流动机理上研究燃机叶片气膜冷却,揭示高温燃气流与冷却流的掺混机理,本文对横向流中单孔射流所形成的剪切涡开展了试验研究。主要研究了速度比、雷诺数及射流角对JICF所形成剪切涡的影响。结果表明:速度比、雷诺数以及射流角会改变主流与射流之间的掺混程度,从而改变射流轨迹的曲率、高度及垂向渗透能力,最终改变剪切涡的特性;迎风涡与背风涡分别是由射流边界层涡与主流边界层涡形成的,当主流边界层涡强度大于射流边界层涡时,背风涡是流场的主导结构,反之,迎风涡将成为流场的主要涡系结构。