二轴框架平台动力学特性及其可镇定性的研究

对一类典型的Yaw-Pitch结构导引头控制回路中被控系统的动力学特性及内环回路的设计进行了研究.建立了描述结构动力学特性的微分方程组,讨论了基座角振动和结构耦合等因素对多自由度框架结构运动-动力学特性的影响.分析了模型中非线性因素和结构参数摄动导致的稳定性问题,给出了内环回路状态反馈校正的保守鲁棒稳定域.     

一种星上MSM型Clos交换结构的调度算法（英文）

针对MSM型Clos交换网络提出一种MMFD调度算法,该算法在输入级交换单元及中间级交换单元输出端口设置了状态指针,在每个时隙开始时刻,调度器根据指针值确定中间级交换单元的配置,然后根据配置状态确定所交换的信元。分析和仿真表明该算法在均匀业务和突发业务下吞吐率都达到了100%,排队时延优于CRRD和SRRD等典型算法。     

一种导电塑料膜电位器辐照试验研究

导电塑料膜电位器是一种空间应用较为广泛的测角装置,但国内空间应用经验较少。尤其是针对其空间耐辐照特性还没有开展过相关试验研究,这是该种电位器能否用于空间长寿命机构中的核心问题之一。文章给出了针对电位器进行辐照试验的试验方法和原理,并对电位器辐照前后的性能进行了对比。试验结果表明该电位器的辐照性能满足型号需求,为其后续应用于空间长寿命机构提供了参考。     

A Distributed Cooperative Localization Algorithm for Mobile Multi-platforms Oriented to Unpredicted Communication Topology

The cooperative localization(CL)is affected by the communication topology among the platforms. Based on the unscented Kalman filtering,the distributed CL(DCL)oriented to the unpredicted communication topology is investigated. To improve the adaptability,the character of the look-up Cholesky decomposition is exploited for the covariance matrix decomposing. Then,the distributed U transformation can be dynamically implemented according to the available communication topology. In the proposed algorithm,the global information is not required for the individual,and only the available information from the neighbor is used. Each platform's state can be estimated independently. The error covariance of the state estimates can be updated in the single platform. The algorithm is adaptive to any serial communication topologies where the measuring to the measured platform is a starting path. The applicability of the proposed algorithm to unpredicted communication topology is improved,remaining equivalent localization performance to free connection communication.     

回归与探索——论郭小川爱情叙事诗的艺术特色

"战士诗人"郭小川在20世纪50年代发表《白雪的赞歌》《深深的山谷》与《严厉的爱》三篇爱情叙事诗,在当时文学政治化大背景下对叙事诗的题材选择做出了新的突破。诗人谱写的爱情叙事诗以复杂的情感以及对人生哲理性的沉思等使叙事与诗完美融合,达到了人性诗化的回归。郭小川在叙事诗中对视角、叙事、意象的构建打破了传统思维惯性,增强了作品的审美张力。     

An active damping vibration control system for wind tunnel models

In wind tunnels, long cantilever sting support systems with low structural damping encounter flow separation and turbulence during wind tunnel tests, which results in destructive low-frequency and big-amplitude resonance, leading to data quality degradation and test envelope limitation. To ensure planed test envelope and obtain high-quality data, an active damping vibration control system independent of balance signal based on stackable piezoelectric actuators and velocity feedback using accelerometer, is proposed to improve the support stability and wind tunnel testing safety in transonic wind tunnel. Meanwhile, a design of powerful sting-root embedded active damping device is given and an active vibration control method is presented based on the mechanism analysis of aircraft model vibration. Furthermore, a self-adaptive fuzzy Proportion Differentiation(PD) control model is proposed to realize control parameters adjustment automatically for various testing conditions. Besides, verification tests are performed in laboratory and a continuous transonic wind tunnel. Experimental results indicate that the aircraft model does not vibrate obviously from -4° to 11° at Ma = 0.6, the number of useable angle-of-attack has increased by 7° at Ma = 0.6 and 5° at Ma = 0.7 respectively, satisfying the requirements of practical wind tunnel tests.     

A Reconfigurable Mobile Launch Pad for Multiple Launchers

A launch pad is an important part of the launch vehicle system.It bears the weight of launch vehicles and payloads,and is burnt due to the high-temperature and ...     

基于FEA的复合材料结构极限承载失效预测

针对复合材料层合板失效分析,基于经典层合板理论与一阶剪切变形理论,通过层合板等效刚度以及各单层板的应力-应变建立了一种并行多尺度方法,并基于此方法采用FORTRAN语言编写了子程序,通过与试验结果以及有限元分析(Finite Element Analysis, FEA)软件内嵌的复合材料失效模型进行对比,证实了并行多尺度方法的可行性,实现了对复合材料层合板在多种工况情况下的渐进损伤分析。     

跨声速风洞调节片式二喉道中心体构型初步研究

新一代先进飞行器的发展,对风洞试验数据的稳定性和精细化水平提出了更高的要求。而二喉道,作为马赫数精确控制系统,可降低试验流场马赫数波动量,提高试验数据稳定性。二喉道从结构构型上可分为调节片式、活动堵块式和栅指式。本文针对调节片加中心体式二喉道,研究不同中心体构型对二喉道性能的影响。首先,利用数值模拟手段定性研究不同中心体构型的二喉道的气动性能;其次,通过风洞试验,设计加工了4种构型的二喉道进行验证试验。数值模拟和试验验证表明:加长板中心体在总压损失和流场控制方面综合性能最好,并在新建的大型连续式风洞中采用了加长板中心体方案。     

基于三维卷积残差网络的无人机高光谱岩性分类

岩性识别和分类是地质学、资源勘查等不可或缺的环节,高光谱遥感的兴起为岩性识别提供新的思路。利用机器学习挖掘岩石高光谱图像中的信息从而准确识别岩性,这具有重要的应用价值。目前用机器学习的方法实现岩石的高光谱影像分类研究中,缺少对空间和光谱信息的充分利用,因此本文使用了一种加入注意力机制的三维卷积残差网络结构,能够有效提取岩石高光谱图像的空间、光谱特征以及空谱联合特征。本实验利用无人机搭载高光谱传感器采集了10种不同类型的岩石样本影像,应用该算法对岩石高光谱图像进行分类。实验结果表明：该算法与传统机器学习算法SVM、RF和深度学习算法ResNet、3D CNN和SSRN相比具有更高的精度。