航天软件中多重中断程序的动态检测方法研究

随着控制系统软硬件平台的设计复杂度不断增加,特别是飞行控制系统中集成的传感器不断增多,中断数量也随之不断增加.本文根据飞控系统的具体特点,使用标记迁移系统对多重中断并发程序进行建模,提出了原子性违背和数据竞争的形式化描述,运用动态偏序化简算法对程序的状态空间进行化简,并设计实现了多重中断控制系统程序的动态检测工具,实验结果表明该检测算法可以在满足对多重中断并发程序错误检测的基础上,大大的缩短检测时间.     

可展开式辐射器热控对航天器轨道调整的适应性分析

为提高航天器热控系统对轨道调整的适应能力，本文研究了与流体回路耦合的可展开式辐射器热控方案在不同轨道高度下的热控性能，分析了不同轨道高度时辐射器面临的热环境的影响，在不同轨道高度下比较了固定辐射器与可展开辐射器的热控特性。结果表明，随着辐射器展开角度的变化，辐射器吸收的空间热流随之发生变化，从而对热控系统的散热能力带来直接影响，调节辐射器的角度可以扩大其对外散热能力。在工程应用中，基于热控流体回路，通过调节可展开式辐射器的展开角度，可以有效提高航天器的轨道热适应能力。     

Improved ZCS-PWM commutation cell for IGBTs application

An improved zero-current-switching pulsewidth-modulated (ZCS-PWM) commutation cell is presented, which is suitable for high-power applications using insulated gate bipolar transistors (IGBTs) as the power switches. It provides ZCS operation for active switches and zero-voltage-switching (ZVS) operation for passive switches. Besides operating at constant frequency and reducing commutation losses, the proposed ZCS-PWM switch cell has no additional current stress and conduction loss in the main switch. To demonstrate the feasibility of the proposed ZCS-PWM commutation cell, it was applied to a boost converter. Operating principle, theoretical analysis, design guidelines, and a design example are described and verified by experiment results obtained from a prototype rated 1 kW and operating at 40 kHz. The PWM switch model and state-space averaging approach is also used to estimate and examine the steady-state and dynamic character of ZCS-PWM boost converter system. Finally, the application of the proposed soft-switching technique in the dc-dc nonisolated converters is presented.     

金属多层膜超晶格结构研究

用高分辨的三晶体x—射线衍射仪测量了Zr、Cu金属交替的多层膜的x—射线小角反射谱。用扩展了的Born—wolf光学模型对Zr、Cu多层膜的x—射线小角反射数据进行了定量分析。结果表明，该金属多层膜在其生长方向具有超晶格结构。在两层金属膜之间的界面上，由于内扩散，形成了界面交混层，它使x—射线小角反射所产生的高阶Bragg峰的强度减弱。由于两种金属膜的晶格不匹配，使高阶Bragg峰加宽。界面的粗糙度可用来模拟x—射线小角反射曲线的阻尼振荡效应。     

220GHz频率步进雷达测距的实验研究

频率步进雷达是一种典型的高分辨雷达,它可以通过瞬时窄带合成宽带实现距离向的高分辨的同时降低A／D和其他设备的负担。文章介绍了220GHz频率步进雷达的工作原理和测距的方法,并对不同距离处的角反射器进行探测。实验结果表明,太赫兹雷达对角反射器距离向的探测距离精度可以达到厘米量级;同时,还对太赫兹雷达的探测距离进行了验证,最远探测距离可达35m。     

A strategic flight conflict avoidance approach based on a memetic algorithm

Conflict avoidance （CA） plays a crucial role in guaranteeing the airspace safety. The cur- rent approaches, mostly focusing on a short-term situation which eliminates conflicts via local adjust- ment, cannot provide a global solution. Recently, long-term conflict avoidance approaches, which are proposed to provide solutions via strategically planning traffic flow from a global view, have attracted more attentions. With consideration of the situation in China, there are thousands of flights per day and the air route network is large and complex, which makes the long-term problem to be a large-scale combinatorial optimization problem with complex constraints. To minimize the risk of premature convergence being faced by current approaches and obtain higher quality solutions, in this work, we present an effective strategic framework based on a memetic algorithm （MA）, which can markedly improve search capability via a combination of population-based global search and local improve- ments made by individuals. In addition, a specially designed local search operator and an adaptive local search frequency strategy are proposed to improve the solution quality. Furthermore, a fast genetic algorithm （GA） is presented as the global optimization method. Empirical studies using real traffic data of the Chinese air route network and daily flight plans show that our approach outper- formed the existing approaches including the GA .based approach and the cooperative coevolution based approach as well as some well-known memetic algorithm based approaches.     

航天器软件风险集成管理方法

为确保航天器软件产品功能、性能符合任务需求,安全、可靠地完成飞行任务,需要对其进行风险管理。文章首先介绍了软件风险管理理论研究现状;然后结合航天器软件强实时性、高可靠性和安全性、维护困难等问题,提出了基于系统集成思想的软件风险控制方法;最后以某航天器为例介绍了该套方法的应用成果。研究结果可为识别航天器软件风险,提高软件产品质量提供参考。     

轴编C/C复合材料组分材料有效性能

利用光学显微镜观测和测量轴编C/C复合材料细观编织结构及其尺寸,建立轴编C/C复合材料有限元模型,通过给出组分材料有效性能的变化区间,构造组分材料性能与轴编C/C复合材料宏观有效性能的对应关系,利用径向基函数(RBF)人工神经网络(ANN)方法,对该高度非线性的对应关系进行训练,通过轴编C/C复合材料宏观实验结果,预报其组分材料的有效性能。结果表明,轴编C/C复合材料面内弹性性能基本相同,在测量时可忽略面内纤维束铺设方向的影响;人工神经网络对训练样本有一定的依赖性,但通过多次随机构造样本训练网络,可得到理想的预测结果,且人工神经网络方法具有很好的容错性,能很好地预报轴编C/C复合材料组分材料的有效性能。     

手持式激光测距仪"测距标准偏差综合评定"的扩展不确定度

在确定的函数关系(数学模型)中,因变量(输出量)随自变量(输入量)的变化规律完全由数学逻辑所确定,自变量到因变量的传递系数(灵敏系数)也可由因变量的标准差和自变量的标准差之比所决定,而与自变量的来历(测量的或者给定的)没有关系[1].本文根据这一基本原理,采用模拟自变量随机变化的方法,成功计算了手持式激光测距仪的测距固定偏差和比例偏差系数的测量不确定度,从而计算出测距标准差综合评定的扩展不确定度,同时解决了复杂的数学模型中多个输入量到输出量的灵敏系数和输出量的不确定度的计算问题.