一种新型矢量推力自转旋翼机的设计与建模

针对传统自转旋翼机巡航速度较低、机动性差的问题,设计一种新型矢量推力自转旋翼机.介绍新型矢量推力自转旋翼机的主要结构,对自转旋翼桨盘、矢量推力装置的原理进行了阐述和建模,并得出该机型的运动学和动力学模型.参考混合控制思路,提出一种双回路混合控制方法,并进行数值仿真.仿真结果表明:该类机型具有较好的飞行稳定性、响应速度和性能,且具有一定的鲁棒性.     

无人驾驶自转旋翼机高度控制

通过对无人驾驶自转旋翼机纵向通道的数学模型和机理分析,研究了旋翼机的高度控制策略,提出了一种以俯仰姿态控制和发动机推力控制为基本控制回路的高度控制方法,实现了自转旋翼机的定高控制和高度跟随控制.通过仿真验证,所提出的无人驾驶自转旋翼机高度控制方法具有较好的高度跟随特性.     

基于分数阶的电动伺服系统控制器设计

针对空空导弹稳定控制系统对舵机伺服控制分系统的快速性和机动性等性能的要求,为了提高舵机伺服分系统的性能,提出了一种基于分数阶的控制器设计方法。首先设计了一个参考整数阶PID,然后以整定后的整数阶PID控制器剪切频率和相角裕度为参考,利用图像法,设计了一个分数阶PD控制器。该算法简单,适于实时控制,抗干扰能力强。仿真结果表明了该算法的有效性,实现了对期望轨迹的高精度跟踪控制。     

无人机伺服作动系统容错控制研究

为了增强伺服作动系统的可靠性,使其当某些特定故障发生时,能够继续工作,提出了一种双余度电动伺服舵机系统。通过建立双余度电动舵机的数学模型,设计舵机控制器,分析双余度舵机的典型故障,选择合适的故障诊断策略,以达到舵回路的故障容错能力。结果表明:采用余度技术后,系统的静态性能和动态性能没有大的改变,但是大大提高了系统的可靠性。     

液压舵机温升问题的分析

介绍了液压舵机的工作原理和主要组成部分,着重分析了液压舵机温升产生的主要原因,并根据温升因素的重要性,重点计算了温升数据.为提高液压舵机设计指标,采用了恒压源电液伺服阀式液压舵机,舵机动力源采用单齿轮泵,并合理设计了各部件的密封形式,有效地控制了液压舵机温升,保证了液压舵机在各种技术要求下的良好使用.     

液压舵机温升问题的分析

介绍了液压舵机的工作原理和主要组成部分，着重分析了液压舵机温升产生的主要原因，并根据温升因素的重要性，重点计算了温升数据。为提高液压舵机设计指标，采用了恒压源电液伺服阀式液压舵机，舵机动力源采用单齿轮泵，并合理设计了各部件的密封形式，有效地控制了液压舵机温升，保证了液压舵机在各种技术要求下的良好使用。     

自抗扰控制器在导弹舵机上的应用研究

空空导弹舵机通常采用PID控制器进行伺服控制,由于舵机运动部分摩擦力变化及其他非线性因素扰动的影响,PID控制器的性能不稳定。近年来逐渐广泛使用的自抗扰控制器对系统扰动有较强的抑制能力,为确定其在舵机控制中的应用可行性,对某型舵机进行了自抗扰与PID控制器应用的对比试验,结果表明,自抗扰控制器用于舵机控制的效果优于常规PID控制器。     

基于模拟退火遗传算法的舵机伺服控制器

根据舵机伺服系统高性能的要求,设计了一种基于全数字三闭环控制策略的舵机伺服控制器系统,对不同的闭环采取不同的控制策略.其中,对系统性能影响最大的位置环采用模拟退火遗传算法优化的PID控制器.实验结果表明该控制策略响应快、鲁棒性强,系统具有较好的动、静态性能和抗干扰能力.     

按重量最小设计冷气舵机的方法

本文介绍冷气舵机的特点，分析了舵机的伺服阀，传动机构，气瓶及功率匹配等问题，提出按重量最小条件进行设计的一些方法。     

基于变结构理论的导弹舵机伺服系统设计

基于变结构控制具有良好的鲁棒性.通过对舵机进行滑模变结构控制的改进设计,改善了舵机的性能,特别是舵机的响应时间,并提高其在干扰条件下的稳定性.     

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.