基于卡尔曼滤波的AR 模型无人自主空中加油预测制导策略

为了改善无人机自主空中加油(AAR)“捕获”阶段中受油机对锥套的“被动跟随”状况,提出一种基于卡尔曼滤波的AR模型无人自主空中加油预测制导策略。利用自回归(auto regressive,AR)模型预测锥套飘摆的未来位置作为受油机导航点,并依据卡尔曼(Kalman)滤波原理对模型进行参数估计,通过加油仿真试验现象对提出方案的实时性能进行定量分析,并提出4种提高实时性的优化措施。仿真结果表明：该算法具有极高的预测精度,改善后的方案满足空中加油场景的实时性要求,能够使加油对接成功率显著提高,对无人机自主空中加油技术的实现具有较重要的意义。     

基于视觉的自主空中加油锥套检测与跟踪

加油锥套检测与跟踪是无人机自主空中加油得以实现的前提,提出一种锥套检测算法,通过添加人工标记,结合颜色通道相减的方法对锥套标记进行提取,利用最大类间方差法进行阈值分割,结合中值滤波、形态学操作完成锥套检测。对原始图像进行噪声、对比度、亮度干扰,验证检测算法的鲁棒性。在该检测算法的基础上,结合上一帧锥套的图像尺寸和锥套运动速度确定锥套的ROI(region of interest)区域,提出一种锥套跟踪算法,在ROI区域内完成对锥套的检测和定位。仿真实验结果表明,引入跟踪后,帧处理速度大大提高,能很好的满足实时性需求。     

基于L1动态逆的自主空中加油对接控制

为实现无人受油机与加油机的自主安全对接,提出基于L1自适应动态逆的无人机自主空中加油对接跟踪控制方法.根据时标分离的原则,将无人受油机的姿态控制分为快、慢回路,采用动态逆方法设计姿态回路控制器,设计L1自适应系统补偿外界气流干扰和系统模型误差,并采用自主空中加油对接段仿真系统对所设计控制系统进行验证.仿真结果表明:该对接跟踪控制系统具有很高的抗干扰能力和鲁棒性,能满足自主空中加油的控制精度要求.     

基于自适应神经网络Backstepping空中加油编队飞行控制

为解决无人机自主空中加油过程加油机和受油机编队飞行控制的问题,提出了对受油机采用导引回路和 姿态回路分离控制策略,采用L1 导引算法设计一种基于自适应神经网络Backstepping 飞行控制器。将改进的L1 导 引算法应用于受油机的横向和纵向的导引,使用自适应神经网络补偿受油机受到的外界的干扰和系统模型误差,神 经网络权值矩阵通过自适应律在线更新,并结合Backstepping 控制方法设计受油机的控制律。仿真结果表明：在受 油机与加油机编队飞行过程中,该设计方法能有效提高受油机的跟踪精度和抗干扰能力,解决空中加油编队飞行控 制问题。     

基于自适应神经网络Backstepping 空中加油编队飞行控制

为解决无人机自主空中加油过程加油机和受油机编队飞行控制的问题,提出了对受油机采用导引回路和 姿态回路分离控制策略,采用L1 导引算法设计一种基于自适应神经网络Backstepping 飞行控制器。将改进的L1 导 引算法应用于受油机的横向和纵向的导引,使用自适应神经网络补偿受油机受到的外界的干扰和系统模型误差,神 经网络权值矩阵通过自适应律在线更新,并结合Backstepping 控制方法设计受油机的控制律。仿真结果表明：在受 油机与加油机编队飞行过程中,该设计方法能有效提高受油机的跟踪精度和抗干扰能力,解决空中加油编队飞行控 制问题。     

基于滑模的空中加油受油机会合制导与控制

为实现空中加油过程中受油机与加油机自主会合,建立满足会合要求的滑模控制面,设计相应制导律.根据受油机与加油机相对位置与速度得出受油机前向加速度指令.基于六自由度受油机动力学模型,采用时标分离将受油机的角运动系统分为快慢回路,采用动态逆方法分别进行系统设计和设计满足追踪会合要求的速度控制律,并以无人机自主跟踪加油机实现会合为例进行仿真.结果表明:该系统能引导受油机实现与加油机的会合,具有良好的动态性能.     

基于可变视场角的空中加油锥套位姿精确测量方法

针对无人机自主空中加油近距视觉高精度导航问题,提出了一种基于可变视场角的空中加油锥套相对位置和姿态精确测量方法。首先构建了由多组不同固定视场角相机组成的双目视觉测量系统,提出了基于非线性滞环特性的相机组切换策略,有效克服了随着距离增加锥套目标在相机图像中比例逐渐减小而导致测量精度降低的问题。在此基础上,使用深度学习YOLO v2算法对首帧图像进行检测与识别,截取感兴趣区域(ROI)并进行图像处理,提取标志灯质心坐标。然后根据双目视觉原理进行三维重建,以计算出标志灯的空间位置。最后根据解析几何关系解算得到锥套相对相机的位置和姿态信息。空中加油对接过程视景仿真和地面实物试验表明,本方法在设定的测量范围内均能达到较高的相对位置和姿态测量精度,且满足实时性要求。     

基于直接升力的空中加油对接飞行控制

为解决传统空中加油对接过程中受油机纵向轨迹跟踪控制存在时间滞后的问题,提出一种基于直接升力的空中加油对接飞行控制方法.采用非线性L1制导的方法生成横纵向加速度指令,设计2种直接升力方案对受油机纵向轨迹控制加以改进,采用动态逆方法对姿态回路设计,通过扩张状态观测器对动态逆内回路进行补偿.仿真结果表明:采用的2种方案均能消除纵向轨迹跟踪的时间滞后,实现受油机纵向轨迹的快速响应,完成空中加油的成功对接.     

读者之声

山东青岛读者李俊问: 飞机如何在空中加油? 飞机在空中加油有软管式和硬管式两种方式: 软管式加油系统主要由输油管卷盘装置、压力供油机构和电控指示装置组成。软管长16～30米,管的末端有外形呈伞形的锥套,内有加油接头(锥管)。若为大型飞机加油,整个加油装置可安装在加油机的机身内部;若为小型飞机加     

一种动态环境下无人机自主导引方法

提出了一种动态不确定环境下无人机( UAV)自主预测导引方法。考虑到无人机探测范围和运动学特性,构建了无人机分区段自主导引模型和轨迹指令求解模型;设计了相应的评价函数;考虑到算法的复杂性,提出采用指令量化和粒子群算法求解导引轨迹指令;并对模型参数取值问题进行了深入的讨论。仿真结果表明,该方法能够实现自主导引无人机迅速接近目标,并对所探测到的威胁进行实时回避,能够实时性运行,具有工程可实现性。     

Nitrosation and Nitration of Tetraacetyldibenzylhexaazaisowurtzitane

Tetraacetyldibenzylhitane (TADBIW) was subjected to debenzylation by nitrosating with inorganic materials available commercially to synthesize tetraacetyldinitrosohexaazaisowurtzitane (TADNSIW). TADNSIW was purified, and its structure was determined by FTIR, 1H NMR, MS and element analysis. The debenzylation reaction of TADBIW gave quantitative benzaldehyde as a by-product. This indicates that the reaction produces an imine cation as an intermediate. Hexanitrohexaazaisowurtzitane (HNIW) was prepared from unpurified TADNSIW with the yield over 96.0 % and the purity more than 98.0 %. And the mechanism of the reaction from TADNSIW to HNIW is proposed to be oxidation of nitroso and nitration of acetyl on the molecule of TADNSIW, This reaction system involved is simple, and the reaction can complete within a short time and under mild conditions. The product can be easily to separate and the waste disposed readily.     

A Robust Algorithm for Watermarking 2D Vector Maps with Low Shape-Distortions

The technique of watermarking has been introduced into 2D vector maps for many potential applications such as protecting the copyright of important GIS （geographical information system） data and tracing the data source of military maps. In most previous works, although the validity of the map data could be preserved during the embedding procedure, the shape-distortions of the map elements are usually neglected which would tend to degrade the invisibility of the watermarking schemes. A shape-preserving algorithm for watermarking 2D vector maps is presented in this paper. A 1D distance sequence extracted from the original map is adopted as the cover data instead of 2D coordinates. A watermark bit is represented by changing the distributions of the cover data. The embedding procedure induces lower shape-distortions than in former works. Experimental results indicate better invisibility of the proposed scheme, as well as its robustness to certain attacks such as map simplification, interpolation, additive noise and most geometric transforms.     

Open Rule-setting System Applied to Conceptual Design of Engines

Open rule-setting method advanced in this paper concentrates on providing designers of engines with a convenient way to express their design innovations and develop the expected prototypes in the early CAD stage, and constitute effective models for the following analysis process of CAE and CAPP. The problems arisen in the process of conceptual design with the traditional experience-based development method are analyzed. Based on those analyses, open rule-setting method is presented and some associated technical problems are discussed. The functional framework of open rule-setting system was built as software engineering methods. The speciality of the engine product as a kind of complex product and the requirement of the engine product based on its structural particularity to rule-setting system are considered carefully. A demonstration is supplied to illustrate how the open rule-setting method enhances the efficiency and quality of the engine conceptual design.     

Research on Linux Network Device Driver

By analyzing the working principle of Linux network device driver, discussing the Linux network driver structure and its key technologies, the general network driver structure and its design methodologies in Linux system are summarized. Through modifying the network device driver of Linux device driver 3rd version snull, c and improving the COW technology, the Zero-Copy technology in Linux （kernel version 2.6.11 ） is implemented. In the end, the success test tells us that the thorough analysis of network device driver is the foundation of many applications, and it also provides a certain improvement to a lot of real applications, even to military application development.     

Improvement and Experiment of the Reamer in Vibra Cutter Against Wave Edge of Titanium Sheet Alloy Parts

By analyzing the influencing factors of part quality making of sheet alloy of titanium by vibra cutter, the shape of upper reamer is set as cylinder and wedge-shaped form, and the lower reamer as plain and hemicycle form, and its main structural parameters are defined as well. Then it is validated further that such improved vibra cutter reamer can be used to process curve-edged parts of titanium alloy sheet. The experimental result shows that the titanium alloy sheet parts processed by above equipment have no sharpen angles for convex parts and evident crevasse of concave-edged part. In summary, such improvement can eliminate the free-waved edge and improve the manufacture quality of titanium alloy sheet parts greatly.     

Experimental Study on the Small Flyer Initiating Behavior of Fine-grained Explosives

The initiating behavior of fine-grained explosives by small flyer is studied. The diameter of small flyer in this device is 1 ram. The test results indicate that the granularity of explosives has great effect on its flyer initiating sensitivity.The flyer initiating sensitivity of the fine-grained explosives is higher and the critical initiating energy is lower than that of common explosives. For common explosive, the flyer initiating sensitivity increases as the density is reduced. But for the fine-grained explosive, the test results are exactly opposite.     

Algorithm for Multi-laser-target Tracking Based on Clustering Fusion

Multi-laser-target tracking is an important subject in the field of signal processing of laser warners. A clustering method is applied to the measurement of laser warner, and the space-time fusion for measurements in the same cluster is accomplished. Real-time tracking of multi-laser-target and real-time picking of multi-laser-signal are introduced using data fusion of the measurements. A prototype device of the algorithm is built up. The results of experiments show that the algorithm is very effective.     

Influence of Installing Error on the Surface Shape Precision of the Axial Symmetry Aspheric Workpiece in Lapping

A method to calculate the surface shape error, which is caused by the installing error between the workpiece and the lapping tool in the process of form lapping, is proposed. The mathematical model which the installing translation error influences on the workpiece surface shape error is established. The changing rule of the error is simulated through the calculating example of the paraboloid workpiece. The results indicate that the surface shape error of the workpiece is increasing with the increase of the installing translation error, it is also increasing gradually along the center point of the curve surface to the edge, and the influence is severer to the curve surface with great curvature than that of the small curvature when the translation error is the same.     

Experimental Research on Output Performances of Giant Magnetostrictive Actuator

The paper introduces the performances of magnetostrictive actuators and its applications, discusses the design methods for the structure and internal magnetic circuit of a giant magnetostrictive actuator, and makes tests on the output displacement and force characteristics for an actuator using homemade magnetostrictive material. The experimental result shows that the actuator has satisfactory output precisions and ranges in transient and stable states, and can be used in lowfrequency vibration control system of precise equipment.     

Robust Graded Sliding Mode Tracking Control for Low Speed Spinning Ballistic Missiles

The nonlinear dynamic model of spinning ballistic missiles is established during the first boosting phase of the missile. Based on the conventional backstepping sliding mode control and the assumption of a two time-scale separation of missile dynamics, a graded sliding mode controller is designed with two sub-sliding surfaces which have invariability to external disturbances and parameter perturbations, and a matrix which comprises three first order low pass filters is introduced to prevent ＂explosion of terms＂. Owing to the upper bounds of the uncertainties are difficult to obtain in advance, adaptive laws are introduced to estimate the values of the uncertainties in real-time. Eventually, the numerical simulation results given to show the proposed controller can ensure the steady flight of missiles.