Ground-Based Cloud Using Exponential Entropy/Exponential Gray Entropy and UPSO

Objective and accurate classification model or method of cloud image is a prerequisite for accurate weather monitoring and forecast. Thus safety of aircraft taking off and landing and air flight can be guaranteed. Thresholding is a kind of simple and effective method of cloud classification. It can realize automated ground-based cloud detection and cloudage observation. The existing segmentation methods based on fixed threshold and single threshold cannot achieve good segmentation effect. Thus it is difficult to obtain the accurate result of cloud detection and cloudage observation. In view of the above-mentioned problems, multi-thresholding methods of ground-based cloud based on exponential entropy/exponential gray entropy and uniform searching particle swarm optimization （UPSO） are proposed. Exponential entropy and exponential gray entropy make up for the defects of undefined value and zero value in Shannon entropy. In addition, exponential gray entropy reflects the relative uniformity of gray levels within the cloud cluster and background cluster. Cloud regions and background regions of different gray level ranges can be distinguished more precisely using the multi-thresholding strategy. In order to reduce computational complexity of original exhaustive algorithm for multi-threshold selection, the UPSO algorithm is adopted. It can find the optimal thresholds quickly and accurately. As a result, the real-time processing of segmentation of groundbased cloud image can be realized. The experimental results show that, in comparison with the existing groundbased cloud image segmentation methods and multi-thresholding method based on maximum Shannon entropy, the proposed methods can extract the boundary shape, textures and details feature of cloud more clearly. Therefore, the accuracies of cloudage detection and morphology classification for ground-based cloud are both improved.     

基于信息熵的危险天气下终端区管制风险评估

终端区结构复杂、飞机事故多,其中危险天气对航空器的安全运行影响极大,因此有必要对危险天气下终端区管制风险进行评估。针对终端区管制系统运行风险性大、易发不安全事件的问题,提出基于风险信息熵的危险天气条件下终端区管制系统风险评估模型。首先,通过分析危险天气条件下管制系统的运行过程,建立管制系统运行中的熵流模型,然后建立危险天气下终端区管制风险评估指标体系,给出评估指标灰色关联度属性的计算方法,利用其反映出的信息熵确定指标权重,最终建立危险天气下终端区管制风险评估模型,并通过算例验证了模型的可用性和有效性。     

Simulation Tools for a Fiber-Optic Based Structural Health Monitoring System

Probability of detection(POD)graphics allow for a change from qualitative to quantitative assessment for every damage detection system,and as such it is a main request for conventional non-destructive testing(NDT)techniques.Its availability can greatly help towards the industrialization of the corresponding Structural health monitoring(SHM)system.But having in mind that for SHM systems the sensors are at fixed positions,and the location of a potential damage would change its detectability.Consequently robust simulation tools are required to obtain the model assisted probability of detection(MAPOD)which is needed to validate the SHM system.This tool may also help for the optimization of the sensor distribution,and finally will allow a probabilistic risk management.INDEUS,simulation of ultrasonic waves SHM system,was a main milestone in this direction.This article deals with the simulation tools for a strain based SHM system,using fiber optic sensors(FOS).FOS are essentially strain/temperature sensors,either with multi-point or with distributed sensing.The simulation tool includes the finite element model(FEM)for the original and damaged structure,and algorithms to compare the strain data at the pre-established sensors locations,and from this comparison to extract information about damage occurrence and location.The study has been applied to the structure of an all-composite unmanned aircraft vehicle(UAV)now under construction,designed at Universidad Politecnica de Madrid for the inspection of electrical utilities networks.Distributed sensing optical fibers were internally bonded at the fuselage and wing.Routine inspection is planned to be done with the aircraft at the test bench by imposing known loads.From the acquired strain data,damage occurrence may be calculated as slight deviations from the baselines.This is a fast inspection procedure without requiring trained specialists,and it would allow for detection of hidden damages.Simulation indicates that stringer partial debondings are detected before they become critical,while small delaminations as those produced by barely visible impact damages would require a prohibited number of sensing lines.These simulation tools may easily be applied to any other complex structure,just by changing the FEM models.From these results it is shown how a fiber optic based SHM system may be used as a reliable damage detection procedure.     

无人机航路规划研究

无人机航路规划的目的是无人机具有对象复杂任务进行快速规划重规划的能力，其中快速而有效的重规划尤其重要。在无人机飞行任务过程中，无人机需要根据局部地形、地貌、威胁等信息以及飞机本身机动能力的限制，实时地计算出飞行航路，并跟踪该航路完成了飞行任务。本文通过比较各种算法在航路规划应用中的优劣性，提出了Dynapath（动态规划）算法在无人机航路规划中的应用，给出了仿真结果。仿真结果表明：Dy-napath算法生成的最优参考航路基本上满足无人机任务飞行的要求，获得了良好的飞行品质。     

基于改进Faster-RCNN的机场场面小目标物体检测算法

针对目前应用于机场视频监控中的卷积神经网络方法存在小目标物体识别准确率较低的问题,本文提出了一种基于Faster-RCNN并结合多尺度特征融合与在线难例挖掘的机场场面小目标检测算法。该算法采用ResNet-101作为特征提取网络,并在该网络基础上建立了一个带有上采样的"自顶向下"的特征融合模块,以生成语义信息更加丰富的高分辨率特征图。并在网络训练过程中,采用在线难例挖掘的训练策略使模型更加鲁棒地对小目标样本进行定位。最后,手工构建了一个包含5 982张图片的机场数据集,用于检测模型的训练和测试。结果表明,本文所提出算法显著提升了机场场面小目标物体检测的准确率,且使整体平均检测准确率达到了80.8%,该结果高于其他先进的目标检测模型。     

大时延扩展CDMA信道下空时多用户检测

提出了基于平行因子分析的大时延扩展CDMA信道下空时多用户检测算法.文中建立了大时延扩展CD-MA信道下接收信号新模型,它将接收信号看成是2个三线性模型之和,并提出了广义三线性交替最小二乘的算法(TALS-G)进行空时多用户检测.仿真结果说明:TALS-G算法具有较好误码率性能,且该方法在阵列扰动情况下仍有较好的性能.它无需信道衰落系数和DOA信息,是盲信号检测方法,具有鲁棒性.     

基于协同进化的复杂低空下多飞行器协同航迹规划方法

由于低空空域环境复杂,威胁通用航空器运行安全。复杂低空多飞行器航迹规划方法是保障安全、提高效率的关键技术。在特定空域范围内,依据地形特点、环境威胁以及飞行器自身物理条件等约束和安全效率等性能指标,为飞行器规划出最优航迹。然而,多飞行器的航迹规划问题存在多约束、强耦合、多目标等难点,现有方法缺乏对问题先验知识的挖掘和利用,导致难以兼顾安全与效率。针对多飞行器航迹规划问题,建立了多飞行器航迹优化 多目标模型。为了进一步提升优化效率,基于启发式算子的自适应差分多目标进化算法,引入多种群协同进化,每个飞行器通过不同种群独立进化,建立合作机制提升种群进化质量,避免陷入极值。最后通过二维与三维仿真实验验证了算法的可行性和有效性。     

基于灰色关联模糊聚类算法优化飞机排故方法

采用灰色关联与模糊聚类原理，建立一种灰色关联的模糊聚类算法，应用该算法可直接对飞机维修经验中的多种排故方法．依排除故障的可能性进行排序，并根据排序结果时排故方法进行相似聚类，从而将排故经验与多因素决策算法进行有效综合．较好地解决了民航飞机故障诊断专家系统中多种故障原因的优化选择问题，并可直接给出排故方法的选择指导，提高专家系统的指导水平和飞机排故效率。文中对算法原理进行了详细介绍，并给出算法实例。     

B747-400型飞机气象雷达显示故障的分析与排除

B747—400货机是南方航空公司的主力货运机型,机载气象雷达系统是用来探测和显示飞机前方航路上危险气象目标的设备,由于该机型搭载的气象雷达型号较新,出现故障后可供查阅的资料较少,通过对该系统显示故障的排故过程分析,阐述对该系统维护的一些经验和建议。     

基于自适应模糊输出观测器的非线性系统鲁棒故障检测

针对一般非线性系统的故障检测，从工程应用的角度提出了一种基于自适应模糊输出观测器的非线性系统鲁棒故障检测方法。该方法以自适应模糊系统构造未知非线性模型的输出观测器，在充分考虑外加噪声干扰和系统误差的情况下，通过对一般反向传播学习算法进行改进，提出采用鲁棒反向传播学习算法调整观测器参数以辩识系统输出，再结合阈值故障检测策略检测系统故障。为保证算法具有较快的收敛速度，本文给出了根据模糊规则确定算法初始参数的选择方法并证明了算法的收敛性。仿真结果表明，对一般非线性系统故障检测，该方法具有有效性和实时性，以及对噪声干扰和系统误差的鲁棒性。     

Gradient Descent Algorithm for Small UAV Parameter Estimation System

A gradient descent algorithm with adjustable parameter for attitude estimation is developed,aiming at the attitude measurement for small unmanned aerial vehicle(UAV)in real-time flight conditions.The accelerometer and magnetometer are introduced to construct an error equation with the gyros,thus the drifting characteristics of gyroscope can be compensated by solving the error equation utilized by the gradient descent algorithm.Performance of the presented algorithm is evaluated using a self-proposed micro-electro-mechanical system(MEMS)based attitude heading reference system which is mounted on a tri-axis turntable.The on-ground,turntable and flight experiments indicate that the estimation attitude has a good accuracy.Also,the presented system is compared with an open-source flight control system which runs extended Kalman filter(EKF),and the results show that the attitude control system using the gradient descent method can estimate the attitudes for UAV effectively.     

极化敏感均匀圆阵中PARAFAC信号检测算法

分析了极化敏感均匀圆阵接收到的信号，该信号具有三线性模型特征。提出了极化敏感均匀圆阵中平行因子信号检测算法。该算法利用三线性交替最小二乘（TALS）算法估计出信源矩阵，然后对其进行判决。仿真结果表明；该算法误码率性能接近于非盲解相关方法;与非盲解相关方法相比，在较高的SNR情况下误码率相差不到2dB；且在阵列扰动情况下仍具有较好的误码率性能。该算法无需空域信息和极化信息，是一种盲鲁棒方法。     

Robust Coordinated Control for a Type of Hypersonic Aircraft

We investigate couplings between variables of attitude dynamics for a hypersonic aircraft,and present a nonlinear robust coordinated control scheme for it.First,we design three kinds of coordinated factors to restrain the strong couplings.Then,we use projection mapping to estimate the uncertain nonlinear functions of the aircraft.Combining the coordinated factors and the designed control laws,we obtain a coordinated torque and assign it to the control deflection commands by using the allocation matrix.A stability analysis demonstrates that all the signals of the closed-loop system are uniformly and fully bounded.Finally,the robust coordinated performance of the designed scheme is verified through numerical simulations.     

基于曲率的指尖检测方法

指尖检测是基于视觉的徒手人机交互系统的关键环节,由于背景的复杂性和系统的实时性要求,导致指尖的精确定位在处理速度和准确性方面存在很大问题。本文针对这一问题,提出了一种简单高效的基于曲率的指尖检测方法。该方法首先将输入视频流基于肤色空间进行二值化,并将二值化后的视频序列作为输入数据;然后采用边缘检测算法提取出肤色区域的边缘(肤色区域的轮廓),在肤色区域的轮廓上根据曲率来对类指尖的点进行检测,并且根据类指尖点的位置关系来判定一个肤色区域是不是手;最后通过过滤算法过滤掉误判手臂点。实验结果表明,该方法在不同的应用背景下都具有很好的检测效果,对光照的鲁棒性也较高,并且能够达到实时检测的效果。     

飞机结冰传感器安装位置确定方法

结冰传感器的安装直接决定了冰的探测效果，在飞机设计阶段往往要耗费巨大的工作量来确定合适结冰传感器安装的位置。本文提出了一种高效确定结冰传感器安装位置的方法，其基本思路是采用数值计算的手段，获得不安装结冰传感器飞机流场的水滴容积分数分布；再根据水滴收集率的定义，得到传感器拟安装区域不同位置的水滴收集率，并与机翼表面的水滴收集率对比；从保证传感器可以起到预警作用的角度出发，进而给出传感器的安装位置。采用该方法对某型民航客机进行了分析，给出了该型飞机适合安装传感器的区域。在此基础上，将传感器加载到对应位置进行数值仿真验证。仿真结果显示:传感器探头处的水滴收集率与不加载传感器时该位置的水滴收集率基本一致，均大于同等条件机翼上的最大水滴收集率，符合飞机的结冰防护需求。本文方法可普遍应用于运输类飞机设计，有效提高结冰防护系统设计的效率。     

飞行器雷达天线罩透波性能研究与测试

介绍了雷达天线罩的功能、特点及电性能要求,论述了雷达天线罩透波性能对天线辐射的影响.在专门的无外界电磁干扰的微波暗室环境中,利用Agilent8530A天线测量系统平台,自行设计了一种简单可靠的测试方法.并结合某型无人机的雷达天线罩进行了实际测试研究,测量精度误差小于0.1 dB.在不同的状态下反复试验得出涂层对透波率的影响,为新型涂层材料的研究提供了精确的实验数据.     

基于图着色模型飞机智能化排班算法的研究

飞机排班问题关系到航空公司的系统运作,作用十分重要。通过对飞机排班问题的分析,把飞机分配问题转化为图着色,应用图着色理论,建立了飞机分配问题的图着色模型,引入时间片算法确定了航班使用飞机的时间冲突集合,根据“先到先服务”的原则给出了飞机分配的顶点序列着色算法。用一个具体的算例,验证了飞机智能化排班比现有航空公司调度员人工排班更先进、更实用、更加节省资源,使资源配置更加合理。     

Guidance and Control Techniques of Carrier-Based Aircraft for Automatic Carrier Landing

We summarize the guidance and control techniques of automatic carrier landing for carrier-based aircraft.First,we analyze the carrier landing operations of the manned fixed-wing aircraft,unmanned fixed-wing aircraft and helicopters.Second,we look into the navigation and guidance system and the flight control methods for current different aircraft.Finally,we draw several conclusions of the development prospects for aircraft carrier landing,including the precision landing control techniques,precision approach and landing guidance techniques,and adaptive,reconfigurable and intelligent flight control techniques.     

面向货物运输的移动平台设计与无人直升机追踪控制

由于无人直升机具有垂直起降、机动性好的特点,使其可用于移动平台之间的货物运输,因此,提出了无人 直升机跟踪移动平台的货物运输方法。设计了一套用于无人直升机追踪实验的动平台,动平台上可放置物品,无人直升机在追踪动平台过程中同时完成物品的拾起和码放。动平台系统由移动小车平台、运动控制器、引导装置以及地面监视软件等组成,采用MEMS-SINS/GPS组合导航系统作为引导装置的核心部件,完成对移动小车平台的位置和速度估计。提出了由单点GPS测量点提供多个目标点位置的方法,可使无人直升机方便快捷地知道需要拾起和码放物品的目标点。设计开发了一套操作简便、显示友好的地面监控软件,辅助移动平台正常运行,能有效监控引导装置与无人直升机的通信。     

无人机自动着陆的导引与控制(英文)

针对无人机自动着陆的需求 ,以某型无人机为对象 ,设计并实现了一种基于机载数字式飞行控制系统和地面无线电跟踪器的自动着陆制导与控制方案。该型无人机的实时仿真和飞行测试结果表明 ,方案设计合理 ,易于实施 ,完全满足无人机自动着陆的要求。