模块化雷达天线阵面平面度误差分析及软件开发

一种基于DAU模块积木化拼装结构的新体制相控阵雷达,其天线阵面大小取决于DAU的数量和拼装形式。为了确保天线低副瓣指标,需要对由DAU拼装形成的天线阵面进行平面度误差分析,并寻求基本拼装单元DAU结构要素与阵面平面度误差之间的联系。在此基础上,通过合理建模和拼装定位公差分析,开发出可信的并与实际阵面比对过的参数化天线阵面平面度误差分析软件。     

大型相控阵天线结构与调整机构一体化设计

针对某大型相控阵天线自重大、加强筋安装位置受限等特点导致天线阵面精度难以保证的工程背景,进行相控阵天线阵面结构方案优化设计。考虑到大型阵面的自重变形导致的柔性特点,提出综合考虑阵面变形后平面度和调整机构精度的一体化优化设计模型,对调整机构支腿的布局进行了优化设计。同时,考虑到加强筋安装位置和型材受限,利用连续化过滤函数,使得型材变量与连续变量进行映射,将离散变量拓扑优化转换为连续变量拓扑优化求解,提高了求解效率,降低了求解的规模。采用上述方法对某大型相控阵雷达进行了案例验证,收到满意的结果。     

轻薄阵列天线阵面形状调整的作动器布局优化

针对轻薄阵列天线结构刚度差、易受复杂环境载荷影响,产生天线阵面结构变形的问题,进行阵面结构补偿设计。首先从阵面结构动力学方程出发,在保证天线阵面可控的前提下,以作动器补偿后阵面变形均方根误差最小和所需的控制能量最少为优化目标,推导并建立了作动器布局的优化模型;并根据阵面变形控制方程计算各作动器的最佳输出力,保证补偿后阵面变形均方根误差最小;最后,以悬臂式阵列天线和某圆形孔径阵列天线模型为例,采用遗传算法对作动器进行了布局优化。分析结果表明,该作动器布局的优化模型可靠,可保证轻型阵列天线阵面的结构变形均方根误差减小80%以上。     

某相控阵天气雷达结构总体设计

相控阵天气雷达是一个较复杂的系统,其布局要求紧凑,天线阵面精度要求高,组件功耗大,与其他天气雷达相比,其结构设计更复杂。文中通过总体布局设计、天线阵面结构设计与天线阵面平面精度控制以及天线座结构设计完成了某型相控阵天气雷达的设计开发工作。同时通过天线与天线座结构刚强度计算和组件热设计计算来确保设计满足要求。目前,该雷达已交付用户,其成功研制对后续类似雷达的设计具有一定的参考价值。     

某有源相控阵气象雷达天线结构设计

随着科学技术的进步和现代雷达的发展,有源相控阵雷达因功能全面,战术指标优良,越来越多地运用在气象领域。但由于大型相控阵天线成本很高,限制了该类型天线的应用,因此能否研发出高性能、低成本的有源相控阵天线关系到其在民品市场中的应用与推广。文中以有源相控阵气象雷达天线为例,分析其结构设计需求,针对其结构设计难点,设计了一种性价比高的天线结构,并对天线阵面进行总体优化布局,对天线骨架,高频箱,裂缝波导,天线阵面吊装和三维布线等方面进行了详细叙述。     

变频调速技术用于相控阵雷达的阵面通风控制

相控阵雷达的天线阵面是整个雷达系统的重要组成部分 ,阵面中移相驱动器的移相精度是保证雷达系统测量精度的重要依据。阵面中的温度和通风控制是保证移相驱动器正常工作的必要条件。传统方法采用风机通风进行降温控制 ,使阵面中温度变化范围较大 ,造成移相驱动器的移相误差加大 ,影响雷达天线的性能指标。采用智能化通风方案 ,由微控制器利用软件控制风机和加热器工作 ,能较好地实现阵面中的环境温度相对稳定 ,改善移相驱动器的移相精度 ,提高整个雷达系统的天线指标和测量精度。本文阐述了以微控制器为核心单元 ,采用变频调速技术来实现天线阵面的智能通风控制 ,对相控阵天线阵面的温度控制方法做出了新的尝试     

相控阵天线碗状变形对其辐射性能的影响分析

如何快速而准确地评估天线阵面结构变形对电性能的影响是工程上亟需解决的关键问题。文中根据某大型相控阵天线设计了3种规格的阵列天线,按照典型的天线阵面碗状变形,分别采用HFSS数值计算方法和有源阵元方向图（Active Element Pattern, AEP）计算方法计算阵元Z向误差和指向误差对电性能的影响。结果表明：当Z向偏差小于λ/20（λ为波长）时,碗状变形对副瓣电平和波束宽度的影响显著,对增益影响较小;当Z向偏差增大到λ/20时,天线增益明显恶化;随着阵元规模的增大,得益于阵元互耦效应,碗状变形对电性能的影响减弱。AEP计算方法忽略了阵元方向图的差异性及互耦效应,导致其计算精度不如HFSS数值计算方法的计算精度高,特别是副瓣计算结果差异明显。该研究可为相控阵天线结构设计参数的确定提供指导。     

某有源相控阵天线阵面风液混合散热系统设计

文中针对某有源相控阵天线设计了一种风液混合散热系统,既解决了相控阵天线高热流密度散热问题,又实现了天线阵面一体化集成设计。针对风液混合阵面的热环控技术要求,从阵面系统布局、热设计、热仿真优化等全流程解析了天线阵面散热系统的设计过程。最后,通过产品实物验证了该天线阵面风液混合散热系统的可行性,可为后续天线阵面散热系统设计提供工程参考。     

风冷有源相控阵天线热设计

T/ R 组件作为天线阵面的主要热源,其最高温和均温性控制是有源相控阵天线热设计的核心内容。文中针对某风冷相控阵天线的热控设计要求,从规划和控制各级传导热阻、接触热阻和对流热阻的全新视角分析了天线阵面的热设计过程,通过仿真对设计进行了优化,并对系统的设计结果进行了热测试,验证了该方法的可行性。     

有源相控阵天线服役性能调控技术进展与挑战

有源相控阵天线广泛应用于地面防空、机载火控、弹载制导、空间通信、电子侦察、气象导航等领域,是未来雷达技术发展的主流。天线在服役过程中不可避免地会受到复杂环境载荷作用,使阵面产生难以预知的结构变形与馈电误差,导致阵元位置偏移、指向偏转、阵元间互耦改变等,最终严重恶化天线的电性能。为此,文中归纳了陆、海、空、天不同服役场景下的环境载荷因素,厘清了稳态载荷、瞬态载荷对天线性能的影响机理,总结了天线阵面形变与馈电系统误差监测方法,进一步从结构补偿、电子补偿两方面给出了天线性能调控关键技术,并探讨了有源相控阵天线服役性能调控未来的研究方向与挑战。     

Minimal Realization of Linear Graph Models for Multi-physics Systems

An engineering system may consist of several different types of components,belonging to such physical"domains"as mechanical,electrical,fluid,and thermal.It is t...     

Quantum Cooperative Robotics and Autonomy

The intersection of Quantum Technologies and Robotics Autonomy is explored in the present paper.The two areas are brought together in establishing an interdisci...     

考虑进油孔有限长滑动轴承油膜力的近似解析解

针对具有进油孔的有限长滑动轴承油膜力求解问题,采用变分原理和分离变量法,求得了有限长滑动轴承油膜压力分布的近似解析表达式。将油膜压力分布的近似解析表达式在油膜存在区域上进行积分,即得到了油膜力。将提出的计算有限长滑动轴承油膜力方法与无限长轴承模型、有限元方法的计算结果进行了比较,发现了提出的方法与有限元方法的计算结果很接近。最后,研究了进油孔位置和进油压力对油膜存在区域、油膜力等的影响,研究结果表明进油孔位置和进油压力对油膜存在区域和油膜力有较大的影响。     

三绕组变压器的双绕组等效建模及在Matpower中的应用

针对实际电网存在着大量的三绕组变压器,但国际上一些著名商业软件,如BPA仿真软件、Matpower这一权威潮流计算开源软件,均只提供双绕组变压器模型,限制了其在具有三绕组变压器的电力系统中的应用的问题,潮流计算是自主开发的电力系统各种应用软件的核心模块,因此依托国际权威开源程序进行二次开发,是一种较好的选择。对Matpower要求的数据格式进行了归纳,对变压器的一般的等值电路及带理想变压器的等值电路和带标幺值的等值电路进行了分析研究,提出了三绕组变压器转换为双绕组等效模型的建模方法,使得原先只适应双绕组变压器的潮流计算软件可以适用于三绕组变压器电网的潮流计算;最后以Matpower软件为例进行了案例计算,并用PSASP仿真软件进行对比验证。研究结果证明,所提出的建模方法是有效的。     

On the Relation of Load to Average Gap in the Contact Between Surfaces with Longitudinal Roughness

A computer simulation model for the contact between longitudinally-oriented rough surfaces has been formulated. This model closely duplicates the actual surf ace contact deformation behavior by taking into account the elastic interactions between the asperities. There were no assumptions made about the shapes, or any deformation behavior of the asperities, except for their obeying the laws of elasticity. The plastic deformations on the high asperity peaks were taken into account by setting a ceiling on their contact pressures at the material hardness value. The simulations used real surface profiles which were digitized from unworn circumferentially ground steel surfaces. Each pair of these profiles was mathematically combined to form an equivalent rough profile pressing against an infinitely rigid flat and having the appropriately adjusted elastic modulus. A total of 28 different pairs of profiles were used in the simulations. Each contacting pair was subjected to 30 different load levels and the local contact pressures and deformations were calculated. The contact simulations yielded some important mathematical relationships between parameters, such as the real area of contact, average gap, and average asperity load through statistical curve fitting. Two analytical functions were generated to relate the average load to average gap and the real area of contact to load.     

INTEGRAL EQUATION METHOD＇S APPLICATION IN HOLE-EDGE STRESS OF COMPOSITE MATERIAL PLATE WITH DIFFERENT SHAPED HOLES

The strength of composite plate with different hole-shapes is always one of the most important but complicated issues in the application of the composite material. The holes will lead to mutations and discontinuity to the structure. So the hole-edge stress concentration is always a serious phenomenon. And the phenomenon makes the structure strength decrease very quickly to form dangerous weak points. Most partial damage begins from these weak points. According to the complex variable functions theory, the accurate boundary condition of composite plate with different hole-shapes is founded by conformal mapping method to settle the boundary condition problem of complex hole-shapes. Composite plate with commonly hole-shapes in engineering is studied by several complex variable stress fimction. The boundary integral equations are founded based on exact boundary conditions. Then the exact hole-edge stress analytic solution of composite plate with rectangle holes and wing manholes is resolved. Both of offset axis loadings and its influences on the stress concentration coefficient of the hole-edge are discussed. And comparisons of different loads along various offset axis on the hole-edge stress distribution of orthotropic plate with rectangle hole or wing manhole are made. It can be concluded that hole-edge with continuous variable curvatures might help to decrease the stress concentration coefficient; and smaller angle of outer load and fiber can decrease the stress peak value.     

电站锅炉模糊风险评价方法研究与应用

针对电站锅炉风险等级评价问题,将模糊综合评价技术应用到电站锅炉风险等级评价中。开展了电站锅炉失效影响因素及模糊评价因素的重要程度分析,建立了一套科学合理适于在线评价的电站锅炉风险评价体系,提出了模糊综合评价技术与改进的模糊层次分析法相结合的模糊风险评价方法,利用改进的模糊层次分析法计算了指标体系中各层指标权重。对某一台电站锅炉的实际运行工况影响子因素进行了模糊风险评价,采用模糊合成算子进行模糊综合运算得到电了站锅炉运行工况影响子因素的评价向量。研究结果表明:电站锅炉的运行工况影响子因素的风险评价等级为第6级,失效可能性等级为小,该电站锅炉运行工况良好。     

Short-Term Relay Quality Prediction Algorithm Based on Long and Short-Term Memory

The fraction defective of semi-finished products is predicted to optimize the process of relay production lines, by which production quality and productivity ar...     

End-to-End Multiview Gesture Recognition for Autonomous Car Parking System

The use of hand gestures can be the most intuitive human-machine interaction medium.The early approaches for hand gesture recognition used device-based methods....     

Non-monotonic material contrast in scanning ion and scanning electron images

30 keV Ga⁺ focused ion beam induced secondary electron (iSE) imaging was used to determine the relative contrast between several materials. The iSE signal compared from C, Si, Al, Ti, Cr, Ni, Cu, Mo, Ag, and W metal layers does not decrease with an increase in target atomic number Z₂, and shows a non-monotonic relationship between contrast and Z₂. The non-monotonic relationship is attributed to periodic fluctuations of the stopping power and sputter yield inherent to the ion–solid interactions. In addition, material contrast from electron-induced secondary electron (eSE) and backscattered electron (BSE) images using scanning electron microscopy (SEM) also shows non-monotonic contrast as a function of Z₂, following the periodic behavior of the stopping power for electron–solid interactions. A comparison of the iSE and eSE results shows similar relative contrast between the metal layers, and not complementary contrast as conventionally understood. These similarities in the contrast behavior can be attributed to similarities in the periodic and non-monotonic function defined by incident particle–solid interaction theory.