自复位式低冲击分离螺母设计研究

设计了一种反推式分离螺母装置,主要完成了关键零部件的设计和校核,对反推式分离螺母装置进行了解锁试验.试验结果表明:分离装置的设计方案正确、工作可靠,其分离冲量小于1N·s,并能够自动复位,为同类产品的设计提供了一定参考.     

冷气分离装置设计参数对冲量的影响

通过应用正交设计法对冷气分离装置进行设计,并开展数值模拟,分析分离装置中气瓶容积、气瓶压力、介质温度和扩张比对有效冲量和后效冲量的影响。结果表明:扩张比对有效冲量的影响程度最大,介质的初始压力和气瓶容积是分离装置冲量影响较大的两个参数,介质温度对有效冲量的影响程度较小而对后效冲量影响较大,分离装置设计中应采用容积较小且设计压力较高的气瓶。     

膨胀管分离装置的分离冲击特性

为了分析膨胀管分离装置在解锁过程中引起结构振动的冲击来源,文中运用LS-DYNA对分离装置的工作过程进行了仿真分析.结果表明:冲击主要来自于膨胀管对分离端框的碰撞以及分离板断裂时应力的释放引起分离板振动;冲击值在结构界面衰减了50％,在结构内部由于应力波衰减效应与结构谐振效应相耦合,冲击值无明显增减.进一步分析得到两种冲击源对结构的振动贡献分别占55％和45％.     

一种低冲击分离螺栓的设计

介绍了一种低冲击分离螺栓的设计,重点介绍了螺栓承载能力的设计以及电起爆器的设计,并对低冲击分离螺栓进行了性能试验.试验结果表明,分离装置的设计方案正确、工作可靠、性能稳定,满足技术要求,为同类产品的设计提供了一定参考.     

一种脉冲推冲器结构设计的方法及实验研究

综合应用固体火箭发动机及火工品的原理设计了一种输出冲量为0.2～0.6N·s,作用时间小于2ms的脉冲推冲器,并根据设计结果制作模型进行实验.实验结果表明设计的脉冲推冲器达到指标要求,并通过实验得到了点火药及主装药药量、喷管类型及密封膜片对脉冲推冲器输出性能的影响规律.     

降低火工解锁螺栓分离冲击的技术研究

为了使火工解锁螺栓在分离过程中产生的分离冲击降到最小,对一种典型的火工解锁螺栓工作原理进行分析,确定了影响分离冲击的关键因素为分离部件的质量和起爆器装药量;并通过结构尺寸优化和起爆器装药小量化两种技术途径,分别使分离部件的质量从83g减小到17g,起爆器装药量从45mg减小到35mg.极限承载力与分离冲击试验结果表明:...     

小型快速火工解锁机构的设计与试验研究

基于SCB(半导体桥)点火技术,设计了一种轴向长度为64mm、径向最大直径为16mm的新型火工解锁机构,并通过拉伸承载力、分离时间与同步性等性能试验,测得其极限承载力不小于20kN、分离时间略大于1ms、同步性为0.126ms,且分离时无烟雾泄漏现象.试验结果表明本文设计的火工解锁机构具有结构尺寸小、分离时间短、同步性...     

一种滚珠式分离解锁螺栓

为满足一种火工品的功能要求,设计了滚珠式分离解锁螺栓。重点研究螺栓承载能力并设计电起爆器, 对滚珠式分离螺栓进行性能试验。实验结果表明：滚珠式分离螺栓的设计方案正确、工作可靠、性能稳定,满足技 术要求,可为同类产品的设计提供参考。     

中小型航天器爆炸螺栓解锁冲击响应特性

爆炸螺栓在中小型航天器分离中有着广泛应用,在解锁过程中会产生高频、强瞬态冲击波,对航天器内部搭载设备形成冲击,因此爆炸螺栓解锁引起的航天器冲击响应是航天工程中必须考虑的问题.基于有限元分析软件Abaqus,采用耦合欧拉-拉格朗日算法建立爆炸螺栓三维流体与固体耦合模型,对爆炸过程进行计算.通过爆炸过程的计算结果,分析螺栓解锁过程中的冲击响应特性,并与试验数据对比验证爆炸螺栓模型的有效性.结果表明,爆炸螺栓解锁可分为爆炸和撞击两个过程,撞击过程产生的冲击响应较爆炸过程更剧烈,其加速度谱峰值约为爆炸过程的3倍.     

高同步性四路弹翼解锁机构的设计与试验研究

采用钝感电起爆器作为动力装置,设计了一种以燃气爆发点为中心,高压燃气沿"十"字型气体通道同步传输做功的弹翼解锁机构。通过对机构输出装药的性能裕度试验、解锁功能试验、解锁同步性试验,测得锁紧销回缩到位,满足功能要求;最大解锁作用时间5ms,解锁同步性0.27ms,解锁过程无燃气泄漏现象。结果表明,本文设计的弹翼解锁机构具有解锁作用时间短、低冲击、同步性高、密封性能好等特点,为同类产品的设计提供了一定参考。     

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.     

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.     

Research on Gear-broken Fault Diagnosis in a Tank Gearbox

A fault diagnosis method of working position gear in a tank gearbox is put forward based on simulating the fault of working position gear in an actual tank, extracting the envelope of vibration signal by Hilbert transformation amplitude demodulation method, and zooming the low-frequency band to envelope signal.