火箭炮位置伺服系统自抗扰控制

针对火箭炮发射时燃气流冲击干扰强和系统参数变化大的特点,以含有速度闭环的实际伺服系统为对象,建立系统模型并进行频域分析,建立了系统的低频和中频近似模型,并在此基础上分别设计了火箭炮位置伺服系统2阶和3阶线性扩张状态观测器及相应的自抗扰控制律,估计系统未建模干扰并在控制输入中予以补偿。比较分析了设计的自抗扰控制律和传统PID控制在伺服跟踪和燃气流冲击干扰下的控制效果。仿真结果表明,火箭炮伺服系统采用提出的控制方法能有效提高跟踪精度,充分抑制燃气流冲击干扰引起的发射平台振动,保证后续射弹命中精度。     

火箭炮两轴耦合位置伺服系统线性自抗扰控制

为了研究方位和俯仰两轴耦合作用下的火箭炮位置伺服系统控制性能,以含有速度闭环的实际系统为对象建立了火箭炮两轴耦合位置伺服系统数学模型。通过频域分析分别提出了方位和俯仰系统的2阶近似模型,设计了两轴系统的线性扩张状态观测器和自抗扰控制器,对系统未建模干扰进行估计并实时补偿。仿真结果表明：该观测器能较好地估计系统总扰动,所设计的控制器有效抑制了两轴负载力矩耦合效应对系统的影响并补偿了火箭炮发射时燃气流冲击力矩强干扰;在伺服跟踪和发射条件下采用所提出的控制方法充分抑制了耦合系统发射平台振动,保证后续射弹精度,性能指标明显优于PID控制。     

基于DSP的交流前馈位置伺服系统的设计

永磁同步电机位置伺服系统经典PID控制具有结构简单,实现方便的优点,但对于等速跟踪和正弦信号跟踪存在跟踪精度低的不足。分析了经典PID控制响应速度慢,对于位置信号跟踪精度低的原因,针对以上2个不足,设计了基于DSP的位置前馈控制器来满足伺服系统的各项要求。实验结果表明,此控制器有效地提高了系统的响应速度和跟踪精度。     

基于H∞方法的伺服系统二自由度鲁棒控制

针对高炮伺服系统存在模型摄动和强外力干扰问题,设计了一种具有二自由度结构强鲁棒性的位置控制器.采用频域方法,通过对转动惯量摄动和高频未建模动态的结构分析,描述了影响伺服系统稳定性的两类主要的不确定性;基于鲁棒控制原理,将位置控制器的设计转化为标准的H∞控制器问题,并通过LMI凸优化方法得到输出反馈次优H∞控制器.仿真结果表明:采用该方法设计的伺服控制系统能实现精确的稳态跟踪,且对模型摄动和外力干扰具有较强的鲁棒性.     

基于分数阶控制的防空火炮伺服系统研究

针对防空火炮对伺服系统高精度和强鲁棒性的要求,本文提出了一种分数阶控制器的设计方法。建立了火炮伺服系统的数学模型,分析了分数阶位置控制器结构,提出并推导了基于相位裕度、截止频率、低频段精度点、振荡度指标等约束条件来进行参数整定的分数阶控制器综合设计方法。仿真结果和实验结果表明,本文所设计的分数阶控制器使得伺服系统具有控制精度高、频带宽、鲁棒性强等显著特点,这为防空火炮伺服系统设计提供了一种新方法。     

某随动系统负载模拟器灰预测模糊PID控制

为了提高某随动系统负载模拟器加载系统的力矩跟踪精度,设计了一种灰预测模糊PID复合控制方法。通过分析随动负载模拟器的系统组成和工作原理,简化力矩电机模型,根据扭矩传感器模型和转动惯量盘模型,建立了随动负载模拟器等效模型,推导出力矩电机输出力矩的传递函数。在传统PID控制的基础上增加了模糊控制器,用于在线调节PID比例、积分和微分参数,使系统响应时间缩短,稳定误差减小,并具有抗干扰能力;同时,加入灰预测模型对加载系统输出力矩补偿。仿真结果表明,所设计的控制方法能够提高加载系统的力矩跟踪精度,且具有较强的抗干扰能力,优于传统PID控制。     

基于分数阶控制的火炮伺服系统

针对防空火炮对伺服系统高精度和强鲁棒性的要求,提出一种分数阶 PIλ控制器的设计方法。建立火炮伺服系统的数学模型,分析分数阶位置控制器结构,基于相位裕度、截止频率、低频段精度点、振荡度指标等约束条件,提出并推导了进行参数整定的分数阶控制器综合设计方法。仿真结果和实验结果表明：该分数阶控制器使得伺服系统具有控制精度高、频带宽、鲁棒性强等显著特点,为防空火炮伺服系统设计提供了一种新方法。     

基于内模控制的分数阶PID算法的稳瞄控制器

研究了分数阶PID在稳瞄系统的控制效果.为了简化分数阶PID的设计,提出一种基于内模控制的分数阶PID设计方法：利用内模原理构造一个仅含整定参数的内模PID,然后通过增加积分阶次λ与微分阶次μ,从而获得分数阶PID控制器;这3个参数可由截止频率、相位裕度和增益鲁棒性约束确定.Matlab仿真与硬件平台试验证明,该控制器相较利用同样约束条件设计的其他控制器,可以使稳瞄系统取得更好的控制性能.     

基于回路成形的涡扇发动机自抗扰控制

为抑制控制器硬件电路不确定性因素和控制中的内外干扰对涡扇发动机高压转子转速控制的影响,设计了线性自抗扰控制器。线性自抗扰控制器由跟踪微分器、扩张状态观测器和误差反馈控制器三部分组成,跟踪微分器负责安排转速指令过渡过程;扩张状态观测器充分利用转速变化的量测信息,可对转速控制信号的内外部干扰进行观测;误差反馈控制器设计时采用了频域校正方法设计控制器,在补偿扩张状态观测器预估干扰的同时,实现发动机的转速控制。最后对某型涡扇发动机控制系统的仿真结果表明,以上自抗扰控制器具有强鲁棒性和抗干扰性能。     

基于跟踪微分器的高超声速飞行器反演控制

针对高超声速飞行器不确定模型,设计了一种基于跟踪微分器的反演控制器.引入跟踪微分器,在存在量测噪声的情况下,对弹道角和攻角进行有效重构.分别设计了基于动态逆的速度控制器和基于反演的高度控制器,并利用跟踪微分器解决了"项数膨胀"问题.为了保证控制器对模型参数摄动的强鲁棒性,设计了一种新型干扰观测器.仿真结果表明,所设计控制器鲁棒性强,并可提供良好的跟踪效果.     

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.