Hybrid partition- and network-level scheduling design for distributed integrated modular avionics systems

Distributed Integrated Modular Avionics (DIMA) develops from Integrated Modular Avionics (IMA) and realizes distributed integration of multiple sub-function areas. Time-triggered network provides effective support for time synchronization and information coordination in DIMA systems. However, inconsistency between processing resources and communication network destroys the time determinism benefiting from partitions and time-triggered mechanism. To ensure such time determinism and achieve guaranteed real-time performance, system design should collectively provide a global communication scheme for messages in network domain and a corresponding execution scheme for partitions in processing domain. This paper firstly establishes a general DIMA model which coordinates partitioned processing and time-triggered communication, and then proposes a hybrid scheduling algorithm using Mixed Integer Programming to produce feasible system schemes. Furthermore, incrementally integrating new functions causes upgrades or reconfigurations of DIMA systems and will generate integration cost. To control such cost, this paper further develops an optimization algorithm based on Maximum Satisfiability Problem and guarantees that the scheduling design for upgraded DIMA systems inherit their original schemes as much as possible. Finally, two typical cases, including a simple fully connected DIMA system case and an industrial DIMA system case, are constructed to illustrate our DIMA model and validate the effectiveness of our hybrid scheduling algorithms.     

利用随机森林算法的卫星控制系统故障诊

针对卫星姿态控制系统存在闭环控制，外部干扰强，进而影响故障诊断准确性和实时性的问题，提出了一种利用随机森林算法的卫星姿态控制系统姿态敏感器和执行器故障诊断方法。首先，采集不同故障情形下卫星姿态控制系统的输入输出数据，进行特征提取。随后通过随机有放回抽样划分训练集和测试集，建立基于随机森林算法的故障诊断模型。利用生成的随机森林模型，对实时输入输出数据进行分类，实现卫星姿态控制系统的故障诊断。利用卫星姿态控制系统半物理仿真平台的数据进行实验，对比实验结果表明：本文所提方法可以实现故障高精度分离，并具有更好的实时性，适用于卫星姿态控制系统的故障诊断问题。     

基于螺纹综合扫描仪的螺纹参数测量方法研究

航空用螺纹的质量和性能直接影响飞机的安全,因此螺纹参数的精确测量至关重要。通过比较几种传统螺纹测量方式的优缺点,确定一种最佳的测量方法——螺纹综合扫描仪测量法。该方法测量精度可靠,参数齐全且效率高。此外,介绍了螺纹综合扫描仪的测量原理,并对其进行了误差分析。利用几种不同的测量方法对同一螺纹进行测量结果的比对,同时做了仪器的重复性和稳定性试验,验证了该测量方法的可靠性。     

应用于MEMS_SINS/GPS组合导航系统的H_∞容错滤波算法

针对基于微机电系统(MEMS,micro electro mechanical system)的捷联惯性导航系统(SINS,strapdown inertial navigation system)与全球定位系统(GPS,global positioning system)组成的组合导航系统中存在不确定干扰并且GPS量测输出中经常含有故障信号的情况,提出一种H∞容错滤波算法,能够对不确定噪声干扰具有鲁棒性,并且能够在检测到故障信号后进行容错计算,使滤波精度始终保持在要求的范围内.基于H∞滤波器,在状态估计方程中加入加权因子,使滤波器具有容错的功能,并且适用于组合导航中量测分量的数量级相差很大的情况.仿真试验结果表明,该算法能有效降低GPS中故障信号的不利影响,使系统在故障存在期间仍能正常工作.     

Analysis of precipitable water vapour characteristics from GNSS measurements during the snow season in Liaoning Province,China

Global Navigation Satellite System (GNSS) remote sensing precipitable water vapour (PWV) data from November 2015 to March 2019 were combined with snowfall observation data and used to analyse PWV characteristics in Liaoning Province during the snow season (from November to March the following year) and their relationship with snowfall. The potential of using GNSS for PWV measurements was demonstrated using sounding data with a correlation coefficient higher than 0.9 and a mean bias error lower than 0.5 mm. According to the GNSS PWV data gathered at 30-min intervals from 68 GNSS stations in Liaoning during the snow season, the monthly PWV average was highest in November and lowest in January. Negative correlations were found between PWV and altitude. Most of the water vapour was concentrated in the low layer of the atmosphere, and the contribution of this vapour to the PWV was higher during the snow season than in summer. A total of 43 snow cases were identified using the snowfall records from 53 GNSS stations, and the characteristics of PWV during these snowfalls were analysed. An increase in PWV was observed before snowfall events. Moreover, the influence of synoptic systems and air mass origins on PWV was analysed based on National Centers for Environmental Prediction (NCEP) reanalysis data and the Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model. The results show that the water vapour condition was better when the synoptic systems or air masses came from areas south of Liaoning.     

基于S3000L的MTA方法在民用飞机领域的应用研究

目前大多数国际主流民用飞机制造商均开始采用S3000L标准进行综合后勤保障设计,以提高飞机的可靠性和维修性。本文通过研究维修任务分析的原理和方法,结合民用飞机研制经验制定出一套可行、有效的维修任务分析操作程序,并运用实例进行了验证和说明,为国内开展民用飞机维修工程分析及其他相关保障工作提供了参考。     

高超声速风洞气动力试验技术进展

高超声速技术是未来航空航天技术的制高点,而高超声速风洞气动力试验是为高超声速飞行器设计和性能评估提供可靠数据不可或缺的重要技术手段。介绍了高超声速气动力试验设备种类和国内外典型的风洞设备,并分析了目前的发展现状。对国内高超声速风洞气动力试验相关测量技术、试验技术、试验数据评估和高超声速气动力标模体系等研究进展进行了总结。同时,还就高超声速气动力试验设备、气动力试验相关技术的未来发展趋势进行了探讨。     

集成BLISCO和iPMA的多学科可靠性设计优化

为解决传统的基于可靠性的多学科设计优化(RBMDO)由于存在优化过程多层嵌套、多学科分析和可靠性分析反复迭代而导致的低效率问题,提出集成两级集成系统协同优化(BLISCO)策略和改进功能测度法(iPMA)的多学科可靠性设计优化方法。首先,基于序列化思想将多学科可靠性设计优化解耦,避免了每次多学科设计优化(MDO)对完整可靠性分析模型的反复调用与迭代。其次,采用高效的更适合复杂工程组织形式的BLISCO策略进行确定性多学科设计优化,摒弃了协同优化的一致性约束和两级集成系统综合法的复杂分析和近似建模问题,提高了计算效率。然后,基于角度更新策略对功能测度法(PMA)进行改进,采用更新角度替代极限状态函数值进行可靠性分析与判别,减少了多学科可靠性分析次数。最后,结合某机型起落架的缓冲器设计实例对所提方法进行验证,结果表明该方法的计算效率较其他方法分别提高了30.93%和19.97%,验证了方法的有效性,且具有工程实用价值。     

燃烧场吸收光谱诊断技术研究进展

基于可调谐半导体激光吸收光谱（TDLAS）的视线测量技术,有能力实现流场温度、速度、组分浓度等参数的快速测量。作为一种有效的诊断工具,TDLAS传感器已经在燃烧和推进系统的研究和开发中获得广泛应用,为改善系统的性能发挥着越来越重要的作用。新应用机会的出现,对传感器提出新挑战的同时也促进了相关技术的进步。概括介绍了TDLAS技术的发展水平、在燃烧场诊断中的应用及未来的潜力,为相关研究人员提供参考。     

综合航电系统实时仿真测试技术研究

研究和建设飞机综合航电系统测试是飞机研制过程中非常重要的环节。通过介绍综合航电仿真系统的原理和功能,提出了一套综合航电系统半物理仿真测试闭环试验系统的建设方案。