潜艇微速与漂流条件下纵向运动特性计算与分析

按照相对运动原理在潜艇阻力和螺旋桨推力中引入海流速度项,建立了海流作用下潜艇纵向动力学方程.用所建立的方程,针对3 000 t级的潜艇开展了定常海流作用下潜艇纵向漂流和微动力航行时的数值模拟与计算.针对模拟计算结果进行了分析研究,提出了"漂流指数"的概念和定义,并按照定义根据所建立的动力学方程在线性假定下推导出了潜艇漂...     

基于升余弦滤波的基带预失真环路延迟补偿

传统的基带预失真环路延迟估计和补偿方法估计过程复杂,收敛速度慢,补偿信号存在混迭失真,影响预失真系统的性能。为此,提出了一种新的基带预失真器环路延迟估计和补偿方法,该方法采用黄金分割法完成环路延迟搜索,用升余弦滤波器完成环路延迟补偿。其环路延迟估计搜索速度快,准确度高,环路延迟补偿后信号失真小,应用该方法的基带预失真系统NMSE指标较传统方法优化17 dB。     

基于LabVIEW和PCI-5640R中频卡的假单脉冲锥扫调制信号模拟

在假单脉冲体制雷达的中频信号模拟中,由DSP配合软件实现的锥扫调制模拟,运算速度慢且数据传输量大。针对该问题,提出了一种基于LabVIEW语言和PCI-5640R中频卡的信号锥扫调制的实现方案,根据中频卡中的FPGA可编程实现多路并行运算的特点,利用LabVIEW对其编程,并进行仿真实验。结果表明：该方法模拟效果好,运算速度快,而且实现简单。     

磁流变阻尼器响应时间仿真与试验研究

响应时间是磁流变阻尼器（Magnetorheological Damper,MRD）重要性能指标之一。为分析MRD响应时间及影响因素,建立了MRD动态响应模型,提出了一种基于Ansoft和Adams联合仿真分析MRD响应时间的方法,并通过仿真与试验相结合的方法分析了阶跃电流幅值、活塞运动速度以及系统刚度等因素对MRD响应时间的影响。仿真结果和试验数据表明：MRD响应时间随活塞速度和系统刚度的增大呈减小趋势,随阶跃电流幅值的升高呈增大趋势。同时证明通过联合仿真分析MRD响应时间和影响因素的方法是有效的。     

基于虚拟触角的自主车辆运动规划方法

在对自主车辆进行运动学分析的基础上,结合反应式行为规划方法和昆虫利用触角进行避障行走的思想,提出了一种使用圆弧形虚拟触角进行运动规划算法,并规划出在各圆弧轨迹片段车辆前轮摆角的参考值。仿真和实验结果表明：通过设置适当的初始参数,该算法能够使自主车辆在行驶过程中完全避开障碍物到达目标点,且轨迹光滑,满足车辆的运动学约束条件。该算法计算简洁、实时性强,适用于底层的实时控制,为自主车辆运动规划提供了一种简便、有效的策略。     

轮式装甲车辆的几何通过性建模与仿真

介绍了轮式装甲车辆通过障碍物的规则,分析了几何障碍物属性和通过判断条件,针对几何障碍物属性,提出了几何障碍物的通过算法,建立了几何通过性模型。采用VC＋＋编程对模型进行了仿真,通过仿真实验验证了算法和模型的可行性。     

小载荷无人机无源定位技术研究

近年来,电子战设备和信号情报系统更加高效小型化,无人机可以携带的载荷种类不断增多.随着无人机的研究、设计和制造水平得到前所未有的提高,在无源定位领域开始发挥越来越重要的作用.从无源定位技术的分类入手,重点研究无人机无源定位的方式、对象和关键技术;以雷达辐射源为例,构建了小载荷无人机虚拟到达时间差(Virtual time differences of arrival,VTDOA)无源定位模型,讨论了对应的定位算法,并给出了仿真试验结论;最后根据最新研究成果展望了无人机无源定位技术的发展趋势.     

面向反恐战术边缘的移动云服务模型架构

分析了新形势下在反恐战术边缘执行反恐任务所面临的问题以及解决以上问题的能力需求,提出了面向反恐战术边缘的移动云服务模型,并分别从总体架构、边缘架构、指控架构和功能架构等方面对模型相关策略和要素进行了描述.分析了该模型的运行机制,为实现在反恐战术边缘提供机动灵活的信息交换和处理能力提供了一种新的途径.     

Mechanical behavior and failure mechanism of polyurea nanocomposites under quasi-static and dynamic compressive loading

Polyurea is an elastomeric material that can be applied to enhance the protection ability of structures under blast and impact loading.In order to study the compressive mechanical properties of SiC/polyurea nanocomposites under quasi-static and dynamic loading,a universal testing machine and split Hop-kinson pressure bar(SHPB)apparatus were used respectively.The stress-strain curves were obtained on polyurea and its composites at strain rates of 0.001-8000 s-1.The results of the experiment suggested that increase in the strain rates led to the rise of the flow stress,compressive strength,strain rate sensitivity and strain energy.This indicates that all of the presented materials were dependent on strain rate.Moreover,these mechanical characters were enhanced by incorporating a small amount of SiC into polyurea matrix.The relation between yield stress and strain rates were established using the power law functions.Finally,in order to investigate the fracture surfaces and inside information of failed specimens,scanning electron microscopy(SEM)and micro X-ray computed tomography(micro-CT)were used respectively.Multiple voids,crazes,micro-cracks and cracking were observed in fracture surfaces.On the other hand,the cracking propagation was found in the micro-CT slice images.It is essential to understand the deformation and failure mechanisms in all the polyurea materials.     

Repeater jamming suppression method for pulse Doppler fuze based on identity recognition and chaotic encryption

Pulse Doppler (PD) fuze is widely used in current battlefield. However, with the threat of repeater jamming, especially digital radio frequency memory technology, the deficiency in the anti-repeater jamming of a traditional PD fuze increasingly emerges. Therefore, a repeater jamming suppression method for a PD fuze based on identity (ID) recognition and chaotic encryption is proposed. Every fuze has its own ID which is encrypted with different chaotic binary sequences in every pulse period of the transmitted signal. The thumbtack-shaped ambiguity function shows a good resolution and distance cut-off characteristic. The ability of anti-repeater jamming is emphatically analyzed, and the results at different signal-to-noise ratio (SNR) show a strong anti-repeater jamming ability and range resolution that the proposed method possesses. Furthermore, the anti-repeater jamming ability is influenced by processing gain, bit error rate (BER) and correlation function. The simulation result validates the theo-retical analysis, it shows the proposed method can significantly improve the anti-repeater jamming ability of a PD fuze.