一种无人机飞行仿真系统设计方法

文中阐述了一种无人机飞行仿真系统的设计方法.介绍了系统的软硬件组成、开发该仿真系统的关键技术(如仿真数据库技术等)及实现方案,并进行了仿真验证,取得较好的效果.     

某小型低空高速无人机控制律设计与仿真

利用自动控制理论的知识,分析并建立了某小型低空高速无人机飞行控制系统的控制律,并采用飞机小扰动运动方程进行了初步的验证计算。利用飞机系统仿真的方法,采用飞机全量扰动运动方程对该型无人机飞行控制系统的控制律进行了仿真验证,结果表明,文中所设计的该型无人机飞行控制系统的控制律可以实现该无人机安全发射、稳定爬升、高度稳定、姿态稳定、航向稳定的要求,进而可以实现无人机按预定航路的飞行。     

基于模糊控制理论的无人机飞控系统设计

由于无人机数学模型中6个气动系数的各个导数是高度和马赫数的一维或二维函数．使用常规飞控系统的无人机控制器结构复杂。控制效果较差。为了解决以上问题,文中提出了基于模糊控制理论的无人机飞控系统设计。并且进行了仿真。仿真结果表明。基于模糊控制理论的无人机飞控系统控制效果优于常规控制器,它也说明模糊理论在无人机飞控系统中有很好的应用前景。     

无人机操纵训练仿真系统

针对无人机操纵手训练中存在的效果不佳和训练周期长等问题,开发了一款成本低廉的软件模拟训练系统。系统基于 DirectX 作为底层驱动,结合无人机运动模型和传感器模型,构建了人员仿真、环境仿真、无人机仿真、传感器仿真等多个部分,解决了对真实坐标与经纬度坐标间的相互转换,传感器仿真的解决方法等难点问题。该系统现已成功应用于无人机操纵的教学和相关无人机组的实践之中,应用结果表明：该系统仿真度高、对运行环境要求低、运行稳定可靠,训练效果显著。     

防空火箭弹对无人机毁伤概率评估模型

为实现防空火箭弹对抗无人机的杀伤效益最大化,提出了一种评估火箭弹最佳引爆距离的方法。文中分析了无人机的易损性、易受攻击性以及火箭弹破片散布误差,以无人机易损区参考坐标系为基础建立了杀伤概率数学模型,得到了杀伤概率随着爆炸距离等参数变化的规律。仿真计算结果表明,此评估模型能够得到火箭弹最佳引爆区间,实现对无人机最大杀伤。     

基于卡尔曼滤波和DDQN算法的无人机机动目标跟踪

为使无人机能够自主、准确地预测目标状态,进而对敌方机动目标进行跟踪,基于卡尔曼滤波和深度强化学习DDQN算法提出了一种在线决策算法。通过构建无人机机动目标跟踪模型和马尔科夫决策过程框架,结合卡尔曼滤波对目标状态进行了准确预测和更新;然后整合无人机自身状态作为神经网络输入,利用DDQN算法进行针对性训练,实现了无人机对机动目标的自主跟踪控制。仿真实验证明,相较于经典DQN算法,基于DDQN算法训练后的无人机,在跟踪任务中能够对目标保持更长的有效跟踪时间、跟踪距离更近,并保持更稳定的飞行状态,最终实现对机动目标的高效跟踪。     

某型火控仿真系统模拟训练质量模糊评判

科学合理的评估能正确反映训练效果．对提高模拟训练效率与效益都具有非凡的意义。对于某型火控系统而言．由于操作较为复杂。对受训人员的评估也相对困难．文中对该型火控仿真系统模拟训练的评估进行了分析和研究．介绍了运用模糊综合评判法对不同人员不定操作进行量化评估的实现。     

某型炮兵气象雷达模拟训练系统总体设计

为克服传统模拟训练系统扩展性和训练环境沉浸感不强的缺点,运用模块化设计方法,对某型炮兵气象雷达模拟训练系统进行总体设计。在分析某型炮兵气象雷达的探测原理及流程的基础上,基于面向对象编程语言VC＋＋6.0和ADO数据源技术体制,实现了模拟训练系统的仿真应用程序;采用Multigen Creator/Vega虚拟仿真技术,构建三维模拟训练场景。结果表明,该设计取得了较好的训练效果,能满足气象分队雷达操作手日常的模拟训练需要。     

某小型无人机导航控制算法研究

研究了可实现小型无人机自主飞行的控制、导航算法。建立了描述无人机运动的状态空间模型,在此基础上分析了开环系统对扰动的响应。针对响应结果,采用最优控制理论设计了带有全维状态观测器的控制器;使用了基于李雅普诺夫向量场的导航算法并对控制器和导航算法进行仿真。研究结果表明,文中给出的控制和导航算法具有良好的性能指标,可跟踪任意航路点,从而可以实现无人机自主飞行。     

小型察打无人机投弹非稳态干扰下六自由度仿真

小型察打无人机投弹前后无人机状态发生突变,且存在机弹干扰,需要分析机弹分离对载机的安全性影响。文中采用基于动网格的非定常流场求解技术耦合外挂武器六自由度运动方程,给出察打无人机实时非稳态干扰气动力。将干扰气动力作用于无人机六自由度模型,建立了包含控制系统的察打无人机投弹六自由度非线性仿真系统。针对某察打无人机,就不同挂弹方案对无人机平台飞行状态的扰动进行了仿真分析。     

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.     

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.     

A Study on the Estimation of Aeroheating upon the Warhead Nose at Supersonic Speed

An expression for estimating the aeroheating on a warhead nose at different supersonic speeds is proposed by incorporating CFD （computational fluid dynamics） and the least-square method. Compared with the traditional estimation formula, the expression is more accurate, convenient and can be used in the optimized design of warheads. The error from the result obtained in the test of a ball cartridge flight is less than 3 %. It satisfies the engineering requirements.     

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.