WB V/I 121高速宽带跟踪型电量隔离传感器原理及其应用

WBV/I 121高速宽带跟踪型电量隔离传感器,是针对高压、大电流等强电,或负载能力很差的弱电,或幅值很小的信号,为克服其干扰、不宜直接与系统连接而设计的,分电压隔离或电流隔离2类.其工作原理是:当电压(电流)输入信号送至输入电路后,被转换成标准电压,并赋予较强的驱动能力;光电隔离电路实现输入信号的线性变换及隔离处理;输出电路将信号放大,输出具有较强驱动能力的标准电压以跟踪输入信号.传感器内部还配备了DC/DC转换器,从辅助电源+E提取能量供输入电路使用.并提供了传感器输出端接至后续设备的高速A/D等电路,信号由计算机等控制采样、处理,以及相应传递函数的应用示例.     

WB智能电量变送器的基本原理及其应用

WB智能电量变送器分为单相和三相两类.该变送器由隔离传感测量、DSP数据处理和通信控制3部分组成,采用单电源或无源工作和DIN卡装式模块化结构.由于采用了模拟信号隔离、非过零交流采样、数字滤波和数字相差补偿,RS-485通信等技术,实现了与现场干扰的全隔离,采样信号数据的标幺化和真有效值,通信网络化等特点.同时详细讨论了该智能变送器通信协议的基本格式,并以一电站自动监测系统为例,介绍了其应用.     

某型高炮随动系统测试平台的设计

基于LabVIEW虚拟仪器技术的某型高炮随动系统测试平台由前端采集插头、信号切换电路和变换电路、数据采集卡组成.信号切换和变换板由JZX-18F继电器和WB系列电量传感器组成.前端采集插头接收测试数据,切换继电器电路传递被测电路板信号.传感器隔离、变换被测信号,AT-MTO-16E-1数据采集卡采集与处理信号.验证表明该测试平台能完成某型高炮随动系统所有信号测试.     

熔池宽度传感器

弧焊熔池宽度传感器包括横着接缝摆动电弧的装置、串联脉冲发生器和转换开关,存贮器的输出端与比较器的第一个输入端相连,与众不同的是,为了提高工作灵敏性和准确性,其中引入了锯齿形电流发生器、激磁电流测量器、熔池宽度调节器、串联微分器、非线性元件及脉冲形成器,这时脉冲形成器的输出端经过转换开关和锯齿形电流发生器与横向摆动电弧装置的输入端相连,电弧摆动装置的输出端经过激磁电流测量器连接存贮器第一个输入端,其第二个输入连接非线性元件的输出端,比较器的第二个输入端连接传感器维持电压的输入端,比较器的输出端连接熔池宽度调节器的输入端,而微分器的输入端连接传感器的测量输入端。     

光电隔离放大器HCPL-7840在电机电流采样中的应用

一种专用于交流伺服电机电流采样的光电隔离放大器HCPL-7840，其输入取自电机任意两相的线电流，输出经偏置放大后送到AD转换器件进行变换处理。实时的电机电流通过一个外部采样电阻得到模拟电压，通过原级采样信号输入端进入芯片，在次级得到一个差分的输出电压，该差分的输出电压正比于电机的电流。     

基于Matlab的输入非平衡条件下矩阵式变换器仿真

通过对矩阵式变换器中双向开关的逻辑控制,可变换其电压和频率.据输入非平衡、输出平衡时矩阵变换器的工作原理,用Matlab建立输入非平衡时矩阵变换器的输入电流偏置角动态调制策略(SVM算法)的仿真模型.该模型由三相非平衡电源、矩阵开关、三相负载和电压表、电流表、示波器等模块和控制策略等构成.     

微机在机场坡度灯控制中的应用

介绍了由恒流调光器、升压变压器,坡度灯角度控制器等构成的机场坡度灯控制系统,系统恒流调光器以80C196为核心计算模块,其高速输入/输出作为可控硅相位同步和触发信号,10位A/D转换器作为系统电流电压输入接口,并通过变参数PI数字电流控制器构成电流闭环系统,同时给出了以80C196汇编语言实现的,根据采样周期进行软启动或变参数PI控制的软件程序框图。     

手机充电器自动测试系统的设计

手机充电器自动测试系统,以GPIB通信卡、PCL720控制卡、PLC、光电传感器、磁感应器等为核心,整个过程由链条带动运输板完成充电器的传输,并自动进行安全规格测试和功能测试.安全规格测试包括输入电流、漏电流、耐压绝缘、温度抗燃、机壳接地、变压输出特性等.功能测试含输出电压、电源和负载调整率.     

基于V/F转换技术的光纤隔离型高压监控电路

高压试验室前端高压充电回路和后端监控电路之间距离为50~80m,高压充电回路最高充电电压为20kV,为了使整个充电系统能够安全稳定工作,研制了基于电压/频率(V/F)、频率/电压(F/V)转换原理的光纤隔离型高压监控电路,实现了高压充电回路和监控电路之间的电气隔离。论述了该电路的结构、原理、硬件设计以及试验结果。实际运行表明:光纤隔离型高压监控电路线性度好,传输精度高,电压显示误差小于5%,维修方便,调试简单,有效地实现了前端高压充电回路和后端监控电路之间的电气隔离,提高了试验人员和后端设备的安全性。     

热敏电阻用宽量程线性温度-频率变换器

RC电路充电的指数电压/时间关系可用于线性化热敏电阻近似成指数的电阻/温度特性。经变换后的输出信号为线性、直接正比于绝对温度的频率。使用标准的、廉价的热敏电阻,在75K的温度范围内,温度误差可小于0.5K。误差的存在主要是由于热敏电阻R(T)特性不完全服从指数关系。这种电路可用于线性化任何输入/输出信号为指数关系的传感器。也可以得到正比于输入电压对数值的输出(即正比于以dB表示的输入信号)。     

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.     

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.     

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 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.