基于CFD方法的前支杆试飞测量装置误差分析

准确可靠的大气数据信息对飞行器的安全至关重要.处于研制阶段的大气数据系统往往存在一定程度的误差,需要在试飞阶段予以校准.试验机上加装的试飞测量装置要求尽可能地接近未受扰动的气流,同时减少对飞机已有大气数据系统的影响.采用计算流体力学方法,对某型民机进行数值模拟,确定了前支杆试飞测量装置的安装位置和长度,获得了前支杆的位置误差并评估了对飞机已有大气数据系统的影响.研究表明,选定前支杆长度情况下,前支杆测量的静压测量误差引起的高度误差偏大,对现有大气数据系统静压亦有一定影响,对迎角影响较小.这一结果可作为某型民机确定空速校准方法的依据,亦可作为其他飞机在空速校准方案选用方面的参考.     

智能探头式大气数据传感器的应用研究

智能探头式大气数据传感器通过测量飞行器表面及附近区域的总压和静压,经大气数据计算机的解算后,得到迎角、速度和高度等参数.对飞行器表面及其周围流场的正确预测和细致分析,是确定智能探头安装位置以及校准算法的关键基础.以某型民用运输飞机为背景,采用计算流体力学技术分析飞机流场,对智能探头式大气数据传感器的安装位置选择以及位置误差修正进行了实例研究.地面试验的结果表明所采用的方法可靠、智能探头的安装位置合理、修正算法准确度高.     

基于AFDX和ACE的大气数据系统设计

以某飞行器作为研制背景,对基于航空全双工交换式以太网（AFDX）和自适应通信环境（ACE）中间件的大气数据系统进行了设计,探索新一代航空数据传输网络和中间件在航空系统中的应用。介绍了AFDX和ACE结构体系。给出了大气数据系统的结构、大气数据的计算公式和计算方法,使用ACE框架对大气数据系统进行了设计,实现大气数据的采集、传输和相关参数的计算。     

某型航空备份仪表的大气数据系统设计

以某型飞机备份仪表原理样机系统的研制为背景,阐述了其大气数据系统的设计思想,详细介绍了大气数据系统的结构、建模及实现等研制过程.该大气数据系统选用精密压力变送器(PPT)测量大气静压和总压,并采用小型单板计算机(686CORE)作为大气数据系统的嵌入式计算机,实现气压式高度表、空速表和马赫数表等大气数据仪表参数的计算,并应用有源矩阵液晶显示器(AMLCD)实时显示飞行参数.     

武装直升机大气数据传感器技术研究进展

大气数据系统提供的大气参数是影响武装直升机飞行安全和武器打击精度的重要因素。根据未来武装直升机对大气数据传感器技术发展的需求,分析了传统武装直升机单轴大气数据传感器技术、双轴大气数据传感器技术、三轴大气数据传感器技术、嵌入式大气数据传感器技术、光学大气数据传感器技术及虚拟大气数据传感器技术存在的技术问题;总结了武装直升机大气数据传感器技术的发展方向。     

气动模型及导航信息辅助的大气参数估计方法

针对无初始风速信息情况下的虚拟大气数据计算问题,提出一种气动模型及导航信息辅助的大气参数粗精两级估计方法.利用飞行器气动模型下的动力学方程,建立与风速直接相关的导航传感器测量模型;采用非线性最小二乘优化方法对风速进行一级估计,并作为滤波初始值;利用扩展卡尔曼滤波,对风速进行二级估计,进而实现大气参数的实时精确估计.实验结果表明,所提方法具有较高的收敛速度和估计精度,可提高大气数据系统的测量范围和可靠性,适用于全飞行包线下攻角、侧滑角、真空速的测量.     

基于硅谐振压力传感器的大气数据系统的实现

详细介绍了Druck RPT 200型硅谐振压力传感器的工作原理,阐述了大气数据系统的结构、建模及硬件实现等研制过程;该系统采用Druck RPT 200型硅谐振压力传感器替代原振动筒式压力传感器测量压力,并采用小型单板计算机作为大气数据系统的嵌入式计算机,实现高度、空速和马赫数等参数的计算,并由显示器实时显示;该大气数据系统体积和重量仅为原系统的1/10,并具有高精度、高分辨率,高稳定性和高重复性的特点。     

大气数据系统一体化研发平台设计与应用

面对新一代机载平台对大气数据系统体积、重量提出的更高要求,通过集成现有技术、采购专用设备、搭建软件环境、建设功能单元,建立大气数据系统仿真、设计、集成和验证一体化研发平台,通过迭代优化设计,实现了大气数据系统设计的小型化、轻量化,有效支撑了某型小型化机载大气数据系统研制,满足了某重点机载平台的使用需求并在多型机载平台大气数据系统研制中的到应用。     

基于新型智能探头的大气数据系统算法研究

开展了基于一种新型半圆柱形探头的大气数据系统算法研究工作。通过计算流体力学(CFD)软件计算获得了半圆柱形探头本体和探头所在处的局部流场信息,建立了该种大气数据系统的气动模型和系统算法模型,并通过仿真验证了算法模型的精度。该项研究工作对大气数据系统及大气数据系统传感器的设计开发具有较高的借鉴和参考价值。     

基于米散射的光学大气数据系统研究

光学大气数据系统较传统大气数据系统在飞行器上应用具有许多显著优势.介绍了基于米散射的激光测速系统基本工作原理,重点讨论了系统中信号混频和微弱信号提取等关键技术.产品样机在实验室的测试结果表明测速精度可达0.75％.     

基于单片机技术的电缆故障定位仪设计

检测飞机电缆故障,在民航机务中是非常重要的;根据飞机电缆的自身特点,提出一种能对其进行有效测试与诊断的方法—低压脉冲法,并利用单片机和CPLD技术,设计出飞机电缆缺陷检测定位装置;该定位仪主要由三部分构成,即:信号采集电路、系统控制电路、人机交互电路;同时,采用两套晶振,既保证了信号的高速采集,又满足系统的低速处理,具有低成本、轻便灵巧、测试准确等特点;同时,除了应用于飞机电缆检修外,还可进一步应用于电信、电力等部门的短距离电缆测试缺陷检测。     

无线传感网络中有向性传感节点的覆盖问题

覆盖问题是无线传感网中最根本的问题之一,它在很大程度上影响到传感的质量。目前有关覆盖问题的研究大多集中于探讨全向性传感节点的覆盖问题,这些方法并不适用于如视频传感这类方向性的传感节点。提出了一个新的(k,ω)-夹角覆盖问题,探讨有向性的传感节点的覆盖问题,为了用最少的传感节点(k,ω)-夹角覆盖所有的目标,提出了一个贪心算法来解决这个问题。另外还提出了三个贡献度函数用于计算每个位置的贡献度,算法根据每个位置所提供的贡献度来决定传感节点的部署位置。仿真结果显示了算法的特性和性能的提升。     

基于立体声信号的声源定位算法研究

提出了一种基于立体声信号的声源定位算法.算法主要分为两个步骤:先进行声达时间差估计,并从中获取传声器阵列中阵元间的声延迟;再利用荻取的声达时间差,结合已知的传声器阵列的空间位置和声速进一步定出具体声源的位置.实践结果表明,该算法是一种准确度高、稳定性好的声源定位方法,并且更加有利于实时声信号的处理.     

Unobtrusive physiological monitoring in an airplane seat

Air travel has become the preferred mode of long-distance transportation for most of the world’s travelers. People of every age group and health status are traveling by airplane and thus the airplane has become part of our environment, in which people with health-related limitations need assistive support. Since the main interaction point between a passenger and the airplane is the seat, this work presents a smart airplane seat for measuring health-related signals of a passenger. We describe the design, implementation and testing of a multimodal sensor system integrated into the seat. The presented system is able to measure physiological signals, such as electrocardiogram, electrodermal activity, skin temperature, and respiration. We show how the design of the smart seat system is influenced by the trade-off between comfort and signal quality, i.e. incorporating unobtrusive sensors and dealing with erroneous signals. Artifact detection through sensor fusion is presented and the working principle is shown with a feasibility study, in which normal passenger activities were performed. Based on the presented method, we are able to identify signal regions in which the accuracies for detecting the heart- and respiration-rate are 88 and 82%, respectively, compared to 40 and 76% without any artifact removal.     

US Air Force relies on computer graphics to evaluate combataircraft performance

The use of computer graphics analysis and other powerful tools to evaluate jet aircraft performance at the US Air Force Flight Test Center, Edwards Air Force Base in California, is described. As many as 14 test versions of the same aircraft model are instrumented with sophisticated sensors to allow flight-test data to be recorded on tape. The tape-recorded data points are used by flight-test engineers to review each aircraft's actual in-flight performance. It was found that computer-generated graphic displays of complicated physical relationships make the job of interpreting aircraft performance data considerably less difficult. The use of interactive graphics to boost productivity is also discussed     

Forwarding via checkpoints: Geographic routing on always-on sensors

Data forwarding is an essential function in wireless sensor networks (WSNs). It is well-known that geographic forwarding is an efficient scheme for WSNs as it requires maintaining only local topology information to forward data to a central gathering point, called the sink (or base station), for further analysis and processing. In this paper, we propose an energy-efficient data forwarding protocol for WSNs, called Weighted Localized Delaunay Triangulation-based data forwarding (WLDT), with a goal to extending the network lifetime. Specifically, WLDT selects as forwarders the sensors with high remaining energy and whose locations lie nearer the shortest path between source sensors and a single sink, thus helping the sensors minimize their average energy consumption. More precisely, WLDT defines checkpoints to build energy-efficient data forwarding paths and uses a 1-lookahead scheme to guarantee data delivery to the sink. We show that WLDT, which favors data forwarding through short Delaunay edges, achieves an energy gain percentage in the order of 55% for the free space model and close to 100% for the multi-path model compared to BVGF and GPSR, which forward data through long distances and which we have slightly updated to account for energy in the selection of next forwarders. We prove that these checkpoints yield an energy gain percentage in the order of 30% in comparison with a similar protocol, called WLDT-w/c (or WLDT without checkpoints), which forwards data via short distances but does not use checkpoints.     

Estimation and validation of lateral-directional stability/control derivatives for the Flight Training Device of a light aircraft

The lateral-directional flight parameters of ChangGong-91, a light airplane developed by Korean Air, are estimated from flight test data by use of the output error method. The reliability of the flight test measurement is examined in engineering judgment, scatter and Cramer–Rao bound, which turns out to be satisfactory with minor defects. Estimated parameter values are validated by comparing the simulated responses with the ones from actual flight tests. The ChangGong-91 FTD turns out to satisfy the qualification of FAA Level 7 FTD in lateral-directional motion. All the necessary practices for generation of high-fidelity data in lateral-directional motion of a light aircraft are successfully performed in this study.     

基于三点重合算法的飞机活动面转角测量研究

针对在飞机活动面转角的拍摄方法或激光跟踪仪方法中,对其样点数据处理算法进行研究,提出了一种可得到较高精度算法,即选取三点建立三角面片,通过将三角面片在前后运动的位置进行分步重合,从这个重合过程中的旋转矩阵可计算出转动角度;通过对选取点与误差关系进行分析,提出了一种选取最优三点的方法以降低位置误差对角度误差的影响;最后,设计精度验证实验;实验结果表明,三点重合算法的误差在0.05度内,误差满足飞机活动面的转角测量要求。     

Two heads better than one: pattern discovery in time-evolving multi-aspect data

Data stream values are often associated with multiple aspects. For example each value observed at a given time-stamp from environmental sensors may have an associated type (e.g., temperature, humidity, etc.) as well as location. Time-stamp, type and location are the three aspects, which can be modeled using a tensor (high-order array). However, the time aspect is special, with a natural ordering, and with successive time-ticks having usually correlated values. Standard multiway analysis ignores this structure. To capture it, we propose 2 Heads Tensor Analysis (2-heads), which provides a qualitatively different treatment on time. Unlike most existing approaches that use a PCA-like summarization scheme for all aspects, 2-heads treats the time aspect carefully. 2-heads combines the power of classic multilinear analysis with wavelets, leading to a powerful mining tool. Furthermore, 2-heads has several other advantages as well: (a) it can be computed incrementally in a streaming fashion, (b) it has a provable error guarantee and, (c) it achieves significant compression ratio against competitors. Finally, we show experiments on real datasets, and we illustrate how 2-heads reveals interesting trends in the data. This is an extended abstract of an article published in the Data Mining and Knowledge Discovery journal.     

飞行器多路温度巡检系统设计

针对因飞机机身局部结冰引起的飞行事故屡屡发生,严重威胁到飞行安全的问题,研究出一种适用于机身各部位温度检测和功能事务管理的多路温度巡检系统,该系统利用机身表皮内嵌的温度传感器感知外界实时的温度变化,并通过RS485通信方式,将温度信息传递给单片机进行数据集中和处理,其结果通过DSP串行口在液晶屏中显示。另外,该系统利用uC/OS—Ⅱ嵌入式操作系统作为其事务管理系统,使整个温度巡检过程简单、高效。实验结果显示:该系统可以实时反映温度传感器所处的环境温度。