InSb磁敏传感器及其应用（中）

五、InSb磁敏电阻和传感器及应用 1、InSb磁敏电阻 与霍尔器件不同,InSb磁敏电阻像其它电阻器一样是一种纯电阻性两端元件,所不同的是它的电阻随磁场的变化而变化。根据图2中几何磁阻效应原理制造的InSb磁敏电阻的基本结构和电阻值与磁场的特性曲线如图10所示。 由图10(a)可见,一个长方体InSb材料被5条In短路条(它具有金属性质)分割     

InSb磁敏传感器及其应用（下）

7、InSb磁敏旋转传感器 图14介绍了利用单个InSb磁敏电阻测量与旋转有关的物理量。在本节中介绍的旋转传感器在原理上和图14一样,但在结构上这种传感器是一个将电子线路、InSb磁敏电阻及永磁铁等组装在一起,接上电源和检测仪表便可应用的整体装置。 图33是一种用于柴油汽车上测量发动机转速的InSb磁敏旋转传感器,电路框图如图34所示。这种传感器的特点是耐高温和各种恶劣环境。工作温度范围为-40～+120℃,电源电压为12～32VDC,最大工     

高灵敏度InSb磁敏电阻的研究

高灵敏度InSb磁敏电阻是制造无接触电位器的核心部件。本文研究的磁敏电阻已被装配到WMC-1型磁敏电位器中,实测结果表明它完全符合设计要求。该磁敏电阻是一种三端式结构,InSb单晶片尺寸为10×10mm~2的正方形,厚度d≈30μm,用环氧胶粘贴在陶瓷基片上。其电阻值R=1～3kΩ,灵敏度;ΔR/R≥50％(B=0.3T)。     

基于InSb磁敏电阻器的齿轮转速传感器

分析了InSb磁敏电阻器的工作原理和温度特性,讨论了利用偏置磁场作用于半桥磁敏电阻构成齿轮转速传感器的测试原理;针对半导体材料对温度十分敏感的特点,提出了利用浮动零点跟踪技术测试齿轮转速的方法,很好地克服了环境温度及磁场变化对磁敏电阻的影响.实验表明:其响应频率为0.5Hz～12kHz.     

InSb磁阻元件与传感器的进展

InSb磁敏电阻及传感器是磁敏元件与传感器的主要品种之一。对这类元件及传感器的工作原理、结构和性能等分别作了简要介绍。其中有分立型磁敏元件,磁敏无接触电位器、旋转传感器、精密小角度角位移传感器、直线位移传感器、压力传感器和图形识别传感器等。除介绍主要技术性能之外,还简要介绍了它们的应用实例。     

InSb-In共晶体薄膜磁阻式齿轮转速传感器

介绍一种用锑化铟—铟 (InSb In)共晶体薄膜磁敏电阻 (MR)制成的齿轮转速传感器 (GVS) ,它由磁敏电阻器和信号处理电路两部分构成。磁敏电阻器的噪声约为 95 μV ,磁敏电阻器与齿轮的距离为5mm时 ,输出信号约为 3mV ,信噪比约 30dB ,测量的准确性可与国外同类产品相媲美。     

一种新型材料的温度控制器的设计

本文设计一种用锑化铟-铟-铟（InSb—In）共晶体薄膜磁敏电阻（MR）制成的双限温控器。实验表明,用InSb—In磁敏电阻作感温磁头设计的此温控器,具有灵敏度高,控温范围宽的优点,实验证明在低温区其灵敏度可以高达30mV／℃以上,常温下也可达到23mV／℃左右;其上下限温度调整范围可以从-40℃到＋120℃之间;测温精度可达到4-0．1℃;另外它还具有性能稳定和对材料要求低等诸多优点,是一种值得推广应用的新型材料温度开关。     

基于InSb磁敏电阻器的脉冲涡流信号处理方法研究

脉冲涡流检测方法是涡流检测技术的一个新兴分支。分析了InSb磁敏电阻器作为脉冲涡流检测元件的工作原理。应用InSb磁敏电阻器的涡流探头检测金属裂纹特征的信息提取方法。对采集的信号首先通过同步累加法处理后再经多项式拟合、小波变换实现对信号的滤波与平滑,最终选用小波变换提取裂纹的特征。实验表明:采用InSb磁敏电阻器作为脉冲涡流检测敏感元件,具有较高的裂纹灵敏度,且可以较好地反映裂纹的深度。     

无触点磁敏电位器自动测试仪研制 ‘

无触点InSb磁敏电位器是利用半导体磁阻效应制成的非接触式传感器,它具有无接触摩擦、分辨率高、寿命长等优点,可广泛地用作角度传感器、直线位移传感器、压力传感器、倾斜角传感器等.天津大学王文生教授等在国内率先研制成功无触点InSb磁敏     

半导体磁敏电阻和传感器

ＩｎＳｂ磁敏电阻元件用磁敏电阻传感器是一种新型的，重要的磁敏元件和传感器。首先，简要介绍了ＩｎＳｂ磁敏电阻元件和磁敏电阻传感器的工作原理，结构，性能等；分别介绍磁敏电阻传感器，磁性墨水文字图形识别传感器，齿轮传感器，磁性编码器，直线位移传感器，齿轮传感器，磁性编码器，直线位移传感器，无接触电位器等工作原理，结构，主要技术性能和应用。     

机器人足球比赛截球策略设计

在机器人世界杯足球锦标赛(TheRobotWorldCup,简称RoboCup)中,截球效率直接影响到比赛的结果。通过足球截球模型,建立方程,从而求出截球位置。解方程的根是提高截球效率的关键,本文采用高效的弦割法来快速计算方程的根。试验发现方程曲线的变化对弦割法解方程根的效率有很大影响,曲线的形状直接影响了弦割法的收敛速度。为加速收敛性,对弦割法进行了优化。最后与优化前的弦割法以及二分法进行了比较,结果表明优化后整体性更为高效,很好地满足了比赛的要求。     

Analytic Controlling Reorientation of a Spacecraft Using a Combined Criterion of Optimality

We consider the problem of optimally controlling the reorientation of a spacecraft (SC) from an arbitrary initial angular state into a given final angular position. We study the case when the minimized functional joins, in the given proportion, the time spent and the integral of the squared modulus of the angular momentum on the reorientation of a SC. The problem is solved in a kinematic setting. We consider two versions of the problem of the optimal rotation of a SC, with bounded and unbounded control. Using the necessary optimality conditions in the form of the Pontryagin maximum principle and the quaternion method for solving control problems on the motion of spacecrafts, we obtain an analytical solution of the posed problem. The solution of the problem is based on the quaternionic differential equation relating the angular momentum vector of a SC with the orientation quaternion of the related coordinate system. We present formalized equations and give computational expressions for constructing the optimal control program. We state the control law as an explicit dependence of the control variables on the phase coordinates. Using the transversality condition as a necessary optimality condition, we determine the maximal value of the modulus of the angular momentum for the optimal motion. For a dynamically symmetric SC, the problem of reorientation in space is solved completely: we obtain the dependences for the optimal law of the change of the angular momentum vector as explicit time functions. We give the results of the mathematical modeling of the motion for optimal control which demonstrate the practical realizability of designed algorithm for controlling the spatial orientation of a SC.     

Application of a global model to the study of Arctic basin pollution: radionuclides,heavy metals and oil hydrocarbons

The status of pollution of the Arctic basin is studied in ecological terms, and the interactions of the Arctic ecosystem with the global system are estimated. A spatial simulation model for the kinetics of pollutants in the Arctic basin is proposed in which the ecological and spatial distribution of the hydrological parameters is taken into account. The model includes blocks describing the flows of pollutants in the trophic chains, the exchange between the water–ice system and the atmosphere and the interaction of the water ecosystem with the global biosphere–climate system. A global model controls the inputs of the simulation model and makes it possible to compute the dynamics of the distribution of pollutants between the Arctic aquatories, which include the Central basin and the peripheral seas. The model uses both published data and the data of the US/Russian expedition to Siberia accomplished in the summer of 1995. Climatic and anthropogenic processes are described in the form of scenarios. The results of computer experiments are given demonstrating the advantages of the simulation model to forecast and to estimate the dynamics of radionuclides, heavy metals and oil hydrocarbons in the Arctic Seas. The total and local pictures of the spatial distribution of pollutants in the Arctic basin are given as functions of various environmental and anthropogenic parameters. It is concluded that the use of the global biospheric model enables the consideration of the interactions between the Arctic basin environment and adjoining territories. This allows estimates to be made of the consequences of the anthropogenic impact on the Arctic ecosystem.     

A method of defuzzification based on the approach of areas' ratio

The new method of defuzzification of output parameters from the base of fuzzy rules for a Mamdani fuzzy controller is given in the paper. The peculiarity of the method is the usage of the universal equation for the area computation of the geometric shapes. During the realization of fuzzy inference linguistic terms, the structure changes from the triangular into a trapezoidal shape. That is why the universal equation is used. The method is limited and can be used only for the triangular and trapezoidal membership functions. Gaussian functions can also be used while modifying the proposed method. Traditional defuzzification models such as Middle of Maxima − MoM, First of Maxima − FoM, Last of Maxima − LoM, First of Suppport − FoS, Last of Support − LoS, Middle of Support − MoS, Center of Sums − CoS, Model of Height − MoH have a number of systematic errors: curse of dimensionality, partition of unity condition and absence of additivity. The above-mentioned methods can be seen as Center of Gravity − CoG, which has the same errors. These errors lead to the fact that accuracy of fuzzy systems decreases, because during the training root mean square error increases. One of the reasons that provokes the errors is that some of the activated fuzzy rules are excluded from the fuzzy inference. It is also possible to increase the accuracy of the fuzzy system through properties of continuity. The proposed method guarantees fulfilling of the property of continuity, as the intersection point of the adjustment linguistic terms equals 0.5 when a parametrized membership function is used. The causes of errors and a way to delete them are reviewed in the paper. The proposed method excludes errors which are inherent to the traditional and non- traditional models of defuzzification. Comparative analysis of the proposed method of defuzzification with traditional and non-traditional models shows its effectiveness.     

A model of the functional state of participants of laboratory markets

The dynamics of psycho-physiological characteristics of participants of laboratory markets in the process of making economical decisions in the decentralized control system is analyzed. For this purpose, the method based on the comparison of stabilographic data with the history of market actions recorded in the course of the experiment is used. The key tool for data analysis is the new segmentation algorithm, which provides efficient partitioning of the stabilographic time series into homogeneous fragments. The segmentation algorithm is obtained as the solution of the problem of estimation of the parameters of the hidden Markov model. The application of this algorithm on the level of individual decision making proves the hypothesis of connection of the stabilogram segmentation time instants of the participant with the time instants of signal actions on the laboratory market. On the level of group decisions, the effect of synchronization of stabilographic time series of participants at the time instant of auction culmination connected with revelation of private information is supported. The degree of synchronization is estimated using a proximity factor calculated based on the specially aggregated canonical correlation.     

Calculation of the parameters of Hidden Markov models used in the navigation systems of surface transportation for map matching: A review

This article provides an overview of the mathematical methods for calculating the parameters of Hidden Markov Models (HMM) used in conjunction with the map coordinates measured by the global positioning systems (GPSs) of mobile navigation systems. These methods are analyzed and compared. There is considered an example of calculating of emission probability of observations emissions and transition probabilities for the Hidden Markov Model of a road network. The example is accompanied by the construction of a states diagram of the HMM and a trellis diagram of the Viterbi algorithm. Using the example, there is estimated the influence of the choice of the value of the standard deviation for the probability density distribution of the minimum distances and the angles difference between the direction of the road element and the direction of the velocity of the vehicle on the probability of the path on the Viterbi trellis. It is proposed to use the functional dependence of the optimal path on the standard deviations and the orthogonal distances for the correction in the process of testing and the practical application of the algorithm of map matching based on the HMM.     

Design of characteristics of air-pressure-controlled hydraulic shock absorbers in an intercity bus

The air-pressure-controlled shock absorber is capable of changing its damping force depending on the air pressure in the air springs. Due to the possibility of improving dynamic properties of all vehicles that use the axles’ air suspensions, BRANO Inc. (the Czech producer of shock absorbers) started to develop semi-active air-pressure-controlled hydraulic telescopic shock absorbers. The SOR C 12 intercity bus is the reference vehicle for which the research and development of controlled shock absorbers is done and on which the shock absorbers are verified. Force–velocity characteristics of the controlled shock absorbers of the axles’ air suspension were designed on the basis of results of computer simulations with the bus multibody models created in the alaska simulation tool. Multibody models of an empty vehicle, a fully loaded vehicle and three variants of a partly loaded vehicle were created. For each weight of the bus two multibody models of various levels of complexity were created. Since the bus multibody models should be used especially for designing force–velocity characteristics of air-pressure-controlled shock absorbers, great attention (in the framework of the possibilities of multibody dynamics) was paid to the correct interpretation of the real behaviour of hydraulic shock absorbers and air springs of the axles’ suspension. As a criterion for the design of the optimum force–velocity characteristics of the controlled shock absorbers, the maximum similarity of the dynamic responses of multibody models of the bus of all the considered weights to dynamic response of the reference multibody model of the bus with the same load as during the experimental measurements on the real vehicle (approx. 71.5% of the maximum loaded vehicle weight) was chosen. In the course of the measurements the non-controlled shock absorbers’ characteristics were optimally tuned for that vehicle weight. Time histories of relative deflections of the axles’ air springs determined during the simulations of the vehicle running over the vertical artificial obstacle were compared. The approach based on the evaluation of the correlation coefficient of two time series was used for the evaluation of the dynamic responses accordance.     

人工免疫在未知木马检测中的应用研究*

针对传统木马检测技术比较被动这一缺陷,提出一种基于人工免疫原理的木马检测方法。利用人工免疫具有自适应以及免疫学习能力的特点,将人工免疫原理应用到木马检测中。分析了数据来源特征,给出了计算抗体与抗原或抗体与抗体之间相似度以及抗体的适应度公式,建立了一个木马检测系统模型;实验测试了利用人工免疫的方式检测木马能有效提高木马检测的检测率,减少误报率。     

Choice of optimal strategy of tumor chemotherapy in Gompertz model

A mathematical model of tumor growth dynamics based on the Gompertz model is considered. It is assumed that tumor cells are affected by a chemotherapeutical agent capable of killing these cells. The degree of action is characterized by the therapy function. Two types of therapy functions are studied: the monotonic and the threshold ones. In the first case, the action of the chemotherapeutical agent is the larger, the higher its concentration. In the second case, the degree of action decreases if the concentration exceeds some threshold value. It is assumed that the concentration of the chemotherapeutical agent is controlled using the control function; the maximum value of this function is limited. The problem of synthesis of optimal control for minimization of the number of tumor cells at the end of the process is formulated. The problem is solved using the dynamic programming method. Exact solutions to the corresponding Hamilton-Jacoby-Bellman equations, which make the synthesis of optimal control possible, are obtained. The results of calculations for optimal therapy strategies are presented.     

Classes of cost functions for string edit distance

Finding a sequence of edit operations that transforms one string of symbols into another with the minimum cost is a well-known problem. The minimum cost, or edit distance, is a widely used measure of the similarity of two strings. An important parameter of this problem is the cost function, which specifies the cost of each insertion, deletion, and substitution. We show that cost functions having the same ratio of the sum of the insertion and deletion costs divided by the substitution cost yield the same minimum cost sequences of edit operations. This leads to a partitioning of the universe of cost functions into equivalence classes. Also, we show the relationship between a particular set of cost functions and the longest common subsequence of the input strings. This work was supported in part by the U.S. Department of Defense and the U.S. Department of Energy.