某型自转旋翼无人机半实物仿真系统

针对某型自转旋翼无人机飞行控制,设计一种半实物仿真系统。介绍半实物仿真系统功能及组成、平台总体设计,详细论述系统硬件、软件设计,并对系统进行仿真试验。结果表明,该半实物仿真系统能真实地模拟自转旋翼无人机飞行控制系统运行环境,验证飞行控制系统逻辑功能及品质,缩短此型号的自转旋翼无人机研制周期。     

微型四旋翼无人机模糊PID 控制

为解决微型四旋翼无人机控制系统存在的鲁棒性差和控制精度低的问题,提出一种模糊PID控制方法。建立微型四旋翼无人机系统动力学数学模型和电机模型,在系统模型的基础上设计模糊PID控制器。通过Matlab/Simulink仿真和飞行试验对所设计的模糊PID控制器的有效性进行验证。仿真实验表明,该算法能提高系统的抗干扰性能和控制精度。飞行试验结果表明,模糊PID控制器可以有效地控制微型四旋翼无人机。     

基于多旋翼无人机视觉惯性里程计的设计与实现

针对GNSS 信号受到干扰或在拒止环境下,多旋翼无人机的导航定位问题,设计一种多旋翼无人机视觉 惯性里程计系统。介绍系统的总体设计方案、硬件选型与设计、软件系统搭建、通信协议规定以及算法设计思路。 实验验证结果表明：该系统可以实际运行在多旋翼无人机上,当GNSS 信号不可用时,仍可向飞控实时提供多旋翼 无人机当前可用位姿,为多旋翼无人机视觉辅助导航设计提供参考。     

幽灵无人机将进行验证飞行

美国Freewing飞行技术公司计划 ,2 0 0 3年的8、9月间对其研制的幽灵 (Spirit)推力矢量无人机进行验证飞行。幽灵无人机实现飞行的方法非常独道　　该公司的负责人称 ,幽灵无人机实现飞行的方法与众不同。无人机推进器的转臂由附着在旋翼桨毂下面的两个控制翼面驱动。当转臂旋转 90°后 ,无人机由垂直转为水平飞行。而垂直飞行时 ,转臂的控制面使旋翼气流向下 ,从而使转臂上升。与传统的偏转旋翼概念不同 ,幽灵无人机没有直接驱动转臂的机械系统。无人机机身枢轴上的两个短翼更有益于无人机的巡航飞行 ,而不是垂直起降。机翼安装角是根据推…     

基于参数估计的四旋翼无人机自适应鲁棒路径跟随控制器

为提高四旋翼无人机的路径跟随精度和飞行鲁棒性,提出一种基于参数估计的四旋翼无人机自适应鲁棒路径跟随控制器。该控制器能够自适应估计无人机模型中的陀螺效应因子和风阻系数,利用估计值补偿系统的控制输入,设计抗干扰项抵消外界环境的负面影响,提高了四旋翼无人机的路径跟随性能和抗干扰能力。建立四旋翼无人机的非线性力学模型,将无人机的路径跟随目标划分为姿态角目标和运动位置目标。利用反步滑模方法和自适应控制方法设计无人机的控制输入方程和估计值更新律。根据Lyapunov方法验证无人机姿态系统和运动位置系统的渐进稳定性。仿真实验和样机实验结果验证了所提控制器的有效性与优越性。     

微小型旋翼无人机总体设计与实现

主要讨论了一种微小型旋翼无人机的设计、制造与试飞验证。在研究涵道风扇式与"单旋翼+气动面"布局的微小型旋翼无人机特点的基础上,提出了微小型旋翼无人机总体设计方案。利用计算流体力学软件Fluent完成了该微型无人机气动面的设计;利用微机电系统惯性测量组件以及地面控制系统完成了该无人机的控制系统设计。微小型旋翼无人机完成了系绳试飞和自由试飞。证明了该微型无人机具有自主悬停能力,并且验证了设计方案的正确性和合理性。     

四旋翼无人机特种弹药悬停发射动力学研究

以某挂载多管发射器的小型四旋翼无人机为研究对象,为研究特种弹药发射对四旋翼无人机飞行稳定性造成的影响,建立了特种弹药发射内弹道模型,通过内弹道编程计算获得了该发射器发射某特种弹药产生的后坐冲量.基于牛顿-欧拉方程建立了无人机及多管发射器的六自由度动力学模型,通过Simulink建模计算,获得了四旋翼无人机及多管发射器的...     

基于Terra Vista 的无人机模拟训练大地形仿真场景创建方法

针对无人机模拟训练中的视景创建问题,设计基于Terra Vista 的大地形仿真场景设计和实现方法。利用 Terra Vista 视景仿真平台,阐述运用细节层次模型的场景设计实现过程和运用实例。测试结果表明：该方法可快速 创建大范围地形地貌场景,满足无人机模拟训练的使用要求。     

多旋翼无人机单目V-SLAM研究综述

视觉同时定位与地图构建(V-SLAM)方法是保证多旋翼无人机在环境先验信息未知情况下正常工作的有效途径,对于多旋翼无人机的定位、导航和路径规划等具有重要意义。针对多旋翼无人机V-SLAM方法的国内外最新研究成果进行综述。首先,在简述V-SLAM分类及发展历程的基础上,综述了国内外具有代表性的基于滤波、基于优化、基于直接法及融合IMU数据的单目V-SLAM系统核心思想及特点;然后,分析了单目V-SLAM系统应用于多旋翼无人机的可行性,介绍了国内外若干从事多旋翼无人机单目V-SLAM研究的团队及其主要研究成果;最后,讨论了近年来V-SLAM的研究热点和发展趋势。     

美国海军为小型舰船研发弹性旋翼无人机

针对小型舰船无法搭载大型无人机的问题,美国海军目前正在研发一种长航时无人监视飞机,这种无人机可像直升机一样进行起降,见下图。这种被称为“弹性旋翼”（Flexrotor）的无人机由美国Aerovel公司设计制造,该公司表示,目前该型无人机还需要几年的时间才能作战使用。然而,海军研究局和设计人员希望该无人机能够较上一代无人机在携带更少设备、需求维护量更少的前提下提供全自主情报、监视和侦查覆盖能力。截止目前,海军研究局已经对该项目投资近50万美元,研发人员正在努力改进该无人机从垂直飞行状态向巡航飞行状态的过渡。     

Stability of the Third Generation Intensifier under Illumination

The stability under illumination of transmission-mode GaAs photocathode sealed in the third generation intensifier is investigated by use of spectral response testing instruments. The variations of spectral response with the illumination times under weak and intense illumination are compared. The variations of photoemission performance parameters are also characterized. The results show that during initial several weak illuminations photocathode behaves no evident decay and a maximum sensitivity is achieved, while under intense illumination the sensitivity of photocathode begin to decrease largely at the first illumination. The calculated performance parameters show that the variation of surface escape probability with illumination times is a direct cause of instability of photocathode. It is also found that under intense illumination peak wavelength is moved towards short-wave and peak response is decreased, which shows that the ability of long-wave response of photocathode is decreased.     

Passive Acoustic Radar for Detecting Supersonic Cruise Missile

A Passive Acoustic Radar is presented as a necessary complement to electromagnetic wave radar, which will be expected to be an effective means for detecting cruise missiles. Acoustic characteristics of supersonic flying projectiles with diverse shapes are expounded via experiment. It is pointed out that simulation experiment could be implemented using bullet or shell instead of cruise missile. Based on theoretical analysis and experiment, the ““acoustic fingerprint““ character of cruise missile is illustrated to identify it in a strong noise environment. After establishing a locating mathematical model, the technique of acoustic embattling is utilized to resolve a problem of confirming the time of early-warning, considering the fact that velocity of sound is much slower than that of light. Thereby, a whole system of passive acoustic radar for detecting supersonic cruise missile is formed.     

Super-resolution Restoration of Remote-sensing Images

A novel image restoration scheme, which is super-resolution image restoration algorithm Poisson-maximum-afterword-probability based on Markvo constraint （MPMAP） combined with evaluating image detail parameter D, has been proposed. The advantage of super-resolution algorithm MPMAP incorporated with parameter D lies in the fact that superresolution algorithm MPMAP model is discrete, which is in accordance with remote-sensing imaging model, and the algorithm MPMAP is proved applicable to linear and non-linear imaging models with a unique solution when noise is not severe. According to simulation experiments for practical images, super-resolution algorithm MPMAP can retain image details better than most of traditional restoration methods; at the same time, the proposed parameter D can help to identify real point spread function （PSF） value of degradation process. Processing result of practical remote-sensing images by MPMAP combined with parameter D are given, it illustrates that MPMAP restoration scheme combined PSF estimation has a better restoration result than that of Photoshop processing, based on the same original images. It is proved that the proposed scheme is helpful to offset the lack of resolution of the original remote-sensing images and has its extensive application foreground.     

Design and Simulation of TF and TA Controller for Missile

A nonlinear terrain following(TF) and terrain avoidance(TA) controller is proposed for missile control systems. Based on classical TF algorithm (adaptive angle method), a new method for TF controller is proposed by using angle of attack. A method of obtaining terrain outline data from digital elevation map (DEM) for TF control is discussed in order to save store space. A TA algorithm is proposed by using bank-to-turn technique. The block control model, which is suitable for backstepping design, is given for nonlinear model of missile. Making full use of the characteristics of the system and combining block control principle and backstepping technique, a robust controller design method is proposed. Uncertainties in every sub-block are allowed, and can be canceled by using the idea of nonlinear damping. It is proved that the state tracking errors are converged to a neighborhood of the origin exponentially. Finally, nonlinear six-degree-of-freedom simulation results for the missile model are presented to demonstrate the effectiveness of the proposed control law.     

Design and Analysis of Test Schemes of Static Postponing Time on Shrapnels Used to Riot Control

The test scheme of static postponing time given in our actual national military test standard on shrapnels used to control riot is a nine-point test scheme on the combined action of three kinds of temperatures and three kinds of pressures,the consumed ammunitions are more excessive. Statistic analysis and tentative checkout about a lot of test data are done,feasibility gists are put forward for optimizing of the test design scheme. The optimizing design and data analysis of test scheme of the item are done by managing uniformity design theory, two scientific and reasonable six-point test schemes are confirmed. The feasibility and reliability of the optimizing design schemes put forward above are proved ulteriorly by test validating. The gained schemes not only have good design uniformity and little ammunition wastage and meet the test demand, but also have better forecast ability for the result data of other points using the mathematic models from the actual test points.     

Expert Systems Aimed at General Design of Projectiles

Expert systems aimed at the general design of projectiles can implement a series of intelligent designs, such as the design of HE shell, the scheme expounded and proved, the emulation analysis and calculation, etc. Aiming at the product design feature, the expert system adopts the object-oriented knowledge representation and all kinds of inference control engines to describe and reason the relevant knowledge regarding the product through the microcomputer. It embodies the foundation of emulation analysis and simulated manufacturing of the shell. It makes use of the method that knowledge expression is combined with condition of inference to carry out the overall design and emulation and reference.The paper gives the ways through which the functions can be achieved, gives the modularization of reference and the design methods of systematization, puts forward the method of knowledge expression and working interface, and supplies a platform for similar products of the shell category that can be quickly designed.     

Design of Non-fragile Satisfactory Estimator for Linear Continuous Perturbed Stochastic Systems

The design problem of non-fragile estimator is addressed for a class of perturbed linear continuous systems. The perturbations occur on the plant and estimator parameters. The estimator designed should force the error system to achieve the desired decay rate and force the steady error variance less than the specified upper bound irrdevancy of the admissible plant perturbations and estimator perturbations. Consistency problem of the decay rate with the variance upper bound is first considered via linear matrix inequality （LMI） approach. The solution of the estimator parameter under specifications to be consistent is then discussed. The consistency condition of specifications and estimator parameter solution are transformed to feasible or minimum problems subject to a set of LMI respectively. The method is illustrated by a numerical example.     

An Improved Scene-based Nonuniformity Correction Algorithm for Infrared Focal Plane Arrays Using Neural Networks

The improved scene-based adaptive nonuniformity correction （NUC） algorithms using a neural network （NNT） approach for infrared image sequences are presented and analyzed. The retlna-like neural networks using steepest descent model was the first proposed infrared focal plane arrays （IRFPA） nonuniformity compensation method, which can perform parameter estimation of the sensors over time on a frame by frame basis. To increase the strength and the robustness of the NNT algorithm and to avoid the presence of ghosting artifacts, some optimization techniques, including momentum term, regularization factor and adaptive learning rate, were executed in the parameter learning process. In this paper, the local median filtering result of Xij （ n ） is proposed as an alternative value of desired network output of neuron Xij （ n ）, denoted as Tij （ n ）, which is the local spatial average of Xij （ n ） in traditional NNT methods. Noticeably, the NUC algorithm is inter-frame adaptive in nature and does not rely on any statistical assumptions on the scene data in the image sequence. Applications of this algorithm to the simulated video sequences and real infrared data taken with PV320 show that the correction results of image sequence are better than that of using original NNT approach, especially for the short-time image sequences （several hundred frames） subjected to the dense impulse noises with a number of dead or saturated pixels.     

Piecewise Filter of Infrared Image Based on Moment Theory

The disadvantages of IR images mostly include high noise, blurry edge and so on. The characteristics make the existent smoothing methods ineffective in preserving edge, To solve this problem, a piecewise moment filter （PMF） is put forward. By using moment and piecewise linear theory, the filter can preserve edge. Based on the statistical model of random noise, a related-coefficient method is presented to estimate the variance of noise. The edge region and model are then detected by the estimated variance. The expectation of first-order derivatives is used in getting the reliable offset of edge. At last, a fast moment filter of double-stair edge model is used to gain the piecewise smoothing results and reduce the calculation. The experimental result shows that the new method has a better capability than other methods in suppressing noise and preserving edge.     

Bistatic Sonar Localization Based on Best Linear Unbiased Estimation

A best linear unbiased estimation （BLUE） algorithm for bistatic sonar localization is proposed. The Cramer-Rao bound for bistatic Sonar and the geometrical dilution of precision （GDOP） in different conditions are given. The simulation results show that the location accuracy of BLUE algorithm is higher than the weighted least square method.