气垫悬浮技术的应用研究

航空制造业对飞机的装配时间和装配质量提出较高要求,建立移动式生产线可有效提高飞机的装配效率和质量。结合Q400机身对接产品移动式生产线的建立,对气垫悬浮装置的工作原理和特点进行深入研究,着重对移动型架的结构进行设计说明和有限元分析,对气垫装置的布置、数量、驱动力等主要技术参数进行详细地计算分析。通过将气垫悬浮装置应用于移动式生产线,证明该装置满足飞机装配高质高效的要求。研究结果可作为其他飞机移动式生产线设计的参考和借鉴。     

校罗差时磁偏差设定为零的机理分析

在飞机地面通常检查时,磁差给定器磁偏差值往往设定为当地磁差,才能得到正确的航向。校正磁罗差时,只有将磁差给定器设定为000.0,不然罗差计算会大大溢出指标。文章通过磁罗差校正的原理和校正方法的论述,进一步分析了校罗差时将磁偏给定器设定为000.0的工作机理。     

发动机某型号节流圈的切削加工

某型号节流圈,其结构特点是壁薄,壁厚仅2.5mm,轴向尺寸小,精度高,刚性差;加工难点为装夹时容易变形,尺寸精度难以保证。通过设计、制作专用夹具,优化加工参数,解决了这一加工难题。这样既保证了产品质量,降低了加工难度又显著提高了生产效率。     

攻角试飞测试基准的误差修正

阐述了攻角测量误差的成因和攻角试飞校准的必要性。选定机头空速管攻角传感器为攻角试飞的测试基准，分析其攻角探测特性，并运用细长旋成体理论重点计算了机体绕流对攻角测量的影响量。探讨了攻角试飞测试基准的误差修正问题。     

准分子激光矫正屈光不正的原理及其实现

研究了准分子激光治疗屈光不正的原理及其实现方法，介绍了准分子激光治疗屈光不正的原理及其种类。在初始角膜模型假设的基础上，提出了能够用于近视、远视和散光等屈光手术的数学模型，计算出切削量和切削的层数，并给出了相应的算法框图。就准分子激光角膜切削机理和“飞点扫描”等关键技术进行了研究。研究成果直接用于准分子激光眼科治疗机，并给出了准分子激光眼科治疗机的原理框图。实验和临床数据表明。取得了满意的手术效果。     

壁面摩擦对风洞侧壁干扰的影响

本文研究了摩擦对风洞侧壁干扰的影响。在以Barnwell为代表开展的一系列侧壁干扰研究中,所有工作都未计及摩擦的影响。我们认为,Barnwell等人的这一处理理论上有缺陷。对此,本文用Karman-Pohlhausen方法对侧壁边界层作了分析,指出摩擦对侧壁干扰有不同程度的影响,具体取决于Pohlhausen参数B的大小;B越小,影响越大。Barnwell略去摩擦项的结果只对应于分离边界层情况,而事实上Barnwell处理的是附着边界层。通过这一分析,本文建立了有摩擦影响的侧壁干扰修正的新形式;考虑到多种因素的影响,初步建议参数B按中间值取为B=3～4。最后,就修正参数δ~*的确定作了一定讨论。     

Using TensorFlow-based Neural Network to estimate GNSS single frequency ionospheric delay (IONONet)

In the last 20?years, and in particular in the last decade, the availability of propagation data for GNSS has increased substantially. In this sense, the ionosphere has been sounded with a large number of receivers that provide an enormous amount of ionospheric data. Moreover, the maturity of the models has also been increased in the same period of time. As an example, IGS has ionospheric maps from GNSS data back to 1998, which would allow for the correlation of these data with other quantities relevant for the user and space weather (such as Solar Flux and Kp). These large datasets would account for almost half a billion points to be analyzed. With the advent and explosion of Big Data algorithms to analyze large databases and find correlations with different kinds of data, and the availability of open source code libraries (for example, the TensorFlow libraries from Google that are used in this paper), the possibility of merging these two worlds has been widely opened. In this paper, a proof of concept for a single frequency correction algorithm based in GNSS GIM vTEC and Fully Connected Neural Networks is provided. Different Neural Network architectures have been tested, including shallow (one hidden layer) and deep (up to five hidden layers) Neural Network models. The error in training data of such models ranges from 50% to 1% depending on the architecture used. Moreover, it is shown that by adjusting a Neural Network with data from 2005 to 2009 but tested with data from 2016 to 2017, Neural Network models could be suitable for the forecast of vTEC for single frequency users. The results indicate that this kind of model can be used in combination with the Galileo Signal-in-Space (SiS) NeQuick G parameters. This combination provides a broadcast model with equivalent performances to NeQuick G and better than GPS ICA for the years 2016 and 2017, showing a 3D position Root Mean Squared (RMS) error of approximately 2?m.     

自适应复合材料薄壁梁形状控制

针对翼面和桨叶等升力面结构,以单闭室薄壁梁为典型结构模型,讨论自适应复合材料薄壁梁的弯曲和扭转,探讨控制结构形状的途径     

航空发动机涡轮盘榫槽的形状优化设计

给出了航空发动机涡轮盘榫槽的形状优化设计的数学模型,并用参变量评价函数法对该数学模型进行等价转换。用基于两点累积信息的原／倒变量展开的对偶优化方法ＤＥＯＲＣＴ对该问题进行求解。算例验证了本文思想及方法的正确性。     

日地平动点卫星两脉冲转移轨道设计

研究基于最小二乘微分修正方法的平动点卫星两脉冲转移轨道设计,推导了考虑高度和航迹角约束的微分修正公式,讨论了该方法的收敛性.以日地L₁点附近的Halo轨道为目标轨道,在圆型限制性三体问题模型下设计了其转移轨道,系统地研究了HOI(Halo Orbit Insertion)点和Halo轨道幅值对转移轨道的影响,给出了HOI点的选择策略,并讨论了应急情况下快速转移轨道设计.数值仿真验证了方法的有效性,选择Halo轨道靠近地球侧的点作HOI点可以获得飞行时间适中的转移轨道.