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1.
在导弹姿态控制系统的故障检测和诊断中,针对BP神经网络自身存在的收敛速度慢等缺点,介绍了一种新型神经网络——带偏差单元的递归神经网络的结构及算法。将它和一改进算法的BP(称为FBP)网络分别用来对同一导弹姿态控制系统进行故障诊断,结果表明,这种算法提高了故障诊断的快速性,增加了诊断的准确性,故障诊断的正确率优于FBP神经网络。  相似文献   

2.
对BP神经网络在蒸汽发生器故障诊断中的应用进行了研究,针对BP神经网络训练时易于陷入局部最小值的问题,利用粒子群优化算法对BP神经网络的权值和阈值进行了优化,并对粒子群优化算法的惯性权值作了自适应调整,以蒸汽发生器为对象进行了故障诊断实验,实验结果表明:自适应调整粒子群优化算法的惯性权值可以提高该算法的收敛速度和精度,利用改进后的粒子群优化算法对BP神经网络进行优化,可以提高BP神经网络的诊断性能。  相似文献   

3.
改进BP神经网络在航空弹药预测中的应用   总被引:3,自引:0,他引:3  
对航空弹药消耗的准确预测是未来战争取胜的一个重要因素,然而战场复杂多变,传统的方法难以进行及时准确地预测.采用了BP神经网络对单个目标航空弹药进行预测,针对常规BP神经网络收敛速度慢、存在所谓"局部最小值"等缺陷,提出了具有全局收敛性的Fletcher-Reeves共轭梯度算法对常规BP网络进行改进,并将改进后的BP网络应用于单个目标航空弹药预测仿真试验中.结果表明,改进BP网络能克服局部极值、快速提高网络收敛速度,并能较为准确地预测航空弹药的需求量.  相似文献   

4.
在某型导弹测试设备故障诊断神经网络知识库的组建过程中,针对BP算法易陷入局部极小、收敛速度慢的缺点,将混沌机制引入常规模糊神经网络算法,利用混沌机制固有的全局游动,逃出权值优化过程中存在的局部极小点,解决了网络训练易陷入局部极小点的问题.通过算法比较和实例结果分析,表明该算法可以有效、可靠地运用于导弹地面测试设备的故障诊断中,并可方便地应用于其它方面.  相似文献   

5.
文中从改进网络结构出发,首先介绍了带偏差单元的递归神经网络的结构及算法,并将它和一改进算法的BP(以后称为FBP)网络分别用来对同一导弹姿态控制系统进行故障诊断.结果表明,该网络能很好地克服BP网络收敛速度慢等缺点,故障诊断的正确率优于该FBP神经网络.由于结构特点,它的应用范围比BP网络更加广泛.  相似文献   

6.
针对传统的BP神经网络学习算法存在易陷入局部极小及收敛速度慢等缺陷,文中提出了利用实数编码改进遗传算法对神经网络进行优化训练,并把训练好的神经网络用于对机械振动信号的预测, 并与传统BP算法以及改进BP算法预测结果进行比较,充分证实了文中方法的有效性.  相似文献   

7.
基于LM优化算法的BP神经网络目标识别方法   总被引:4,自引:0,他引:4  
误差反向传播算法(Back-propagation简称BP算法)是当前前馈神经网络训练中应用最多的算法。针对BP算法存在局部极小点,收敛速度慢等缺点,通过采用基于优化理论的Levenberg-Marquardt(LM)算法来改进BP算法。对提取的目标瞬态特性特征归一化后作为BP神经网络的输入,通过Matlab仿真对网络进行调整,并将训练好的网络进行军事目标识别。结果表明,该方法合理可行,且收敛速度快,预测精度高,为目标识别提供了一种新方法。  相似文献   

8.
通过遗传算法的全局寻优能力优化BP神经网络的初始参数,使其收敛速度快、并能收敛至全局最小点,再利用BP网络来进行精确求解;实验表明:将二者有机结合后能对各种故障进行可靠的分类,有效地提高了故障诊断的效率和准确度。  相似文献   

9.
简要介绍了雷达电路故障模式和BP神经网络的算法,针对雷达故障诊断的复杂性,提出了采用神经网络技术实现雷达的故障诊断。并以典型故障为例,设计了一个基于BP网络的故障诊断系统,通过实际仿真和应用,取得了较好的效果。  相似文献   

10.
在改进遗传算法和BP算法的基础上提出了一种普适的遗传算法与神经网络结合的算法模型.探讨了用改进的遗传算法与BP算法相结合对神经网络权系数进行优化;并将其应用于交流电机故障识别.实践表明,该方法是一种行之有效的智能故障诊断新途径.  相似文献   

11.
Tetraacetyldibenzylhitane (TADBIW) was subjected to debenzylation by nitrosating with inorganic materials available commercially to synthesize tetraacetyldinitrosohexaazaisowurtzitane (TADNSIW). TADNSIW was purified, and its structure was determined by FTIR, 1H NMR, MS and element analysis. The debenzylation reaction of TADBIW gave quantitative benzaldehyde as a by-product. This indicates that the reaction produces an imine cation as an intermediate. Hexanitrohexaazaisowurtzitane (HNIW) was prepared from unpurified TADNSIW with the yield over 96.0 % and the purity more than 98.0 %. And the mechanism of the reaction from TADNSIW to HNIW is proposed to be oxidation of nitroso and nitration of acetyl on the molecule of TADNSIW, This reaction system involved is simple, and the reaction can complete within a short time and under mild conditions. The product can be easily to separate and the waste disposed readily.  相似文献   

12.
The technique of watermarking has been introduced into 2D vector maps for many potential applications such as protecting the copyright of important GIS (geographical information system) data and tracing the data source of military maps. In most previous works, although the validity of the map data could be preserved during the embedding procedure, the shape-distortions of the map elements are usually neglected which would tend to degrade the invisibility of the watermarking schemes. A shape-preserving algorithm for watermarking 2D vector maps is presented in this paper. A 1D distance sequence extracted from the original map is adopted as the cover data instead of 2D coordinates. A watermark bit is represented by changing the distributions of the cover data. The embedding procedure induces lower shape-distortions than in former works. Experimental results indicate better invisibility of the proposed scheme, as well as its robustness to certain attacks such as map simplification, interpolation, additive noise and most geometric transforms.  相似文献   

13.
Open rule-setting method advanced in this paper concentrates on providing designers of engines with a convenient way to express their design innovations and develop the expected prototypes in the early CAD stage, and constitute effective models for the following analysis process of CAE and CAPP. The problems arisen in the process of conceptual design with the traditional experience-based development method are analyzed. Based on those analyses, open rule-setting method is presented and some associated technical problems are discussed. The functional framework of open rule-setting system was built as software engineering methods. The speciality of the engine product as a kind of complex product and the requirement of the engine product based on its structural particularity to rule-setting system are considered carefully. A demonstration is supplied to illustrate how the open rule-setting method enhances the efficiency and quality of the engine conceptual design.  相似文献   

14.
By analyzing the working principle of Linux network device driver, discussing the Linux network driver structure and its key technologies, the general network driver structure and its design methodologies in Linux system are summarized. Through modifying the network device driver of Linux device driver 3rd version snull, c and improving the COW technology, the Zero-Copy technology in Linux (kernel version 2.6.11 ) is implemented. In the end, the success test tells us that the thorough analysis of network device driver is the foundation of many applications, and it also provides a certain improvement to a lot of real applications, even to military application development.  相似文献   

15.
By analyzing the influencing factors of part quality making of sheet alloy of titanium by vibra cutter, the shape of upper reamer is set as cylinder and wedge-shaped form, and the lower reamer as plain and hemicycle form, and its main structural parameters are defined as well. Then it is validated further that such improved vibra cutter reamer can be used to process curve-edged parts of titanium alloy sheet. The experimental result shows that the titanium alloy sheet parts processed by above equipment have no sharpen angles for convex parts and evident crevasse of concave-edged part. In summary, such improvement can eliminate the free-waved edge and improve the manufacture quality of titanium alloy sheet parts greatly.  相似文献   

16.
The initiating behavior of fine-grained explosives by small flyer is studied. The diameter of small flyer in this device is 1 ram. The test results indicate that the granularity of explosives has great effect on its flyer initiating sensitivity.The flyer initiating sensitivity of the fine-grained explosives is higher and the critical initiating energy is lower than that of common explosives. For common explosive, the flyer initiating sensitivity increases as the density is reduced. But for the fine-grained explosive, the test results are exactly opposite.  相似文献   

17.
Multi-laser-target tracking is an important subject in the field of signal processing of laser warners. A clustering method is applied to the measurement of laser warner, and the space-time fusion for measurements in the same cluster is accomplished. Real-time tracking of multi-laser-target and real-time picking of multi-laser-signal are introduced using data fusion of the measurements. A prototype device of the algorithm is built up. The results of experiments show that the algorithm is very effective.  相似文献   

18.
A method to calculate the surface shape error, which is caused by the installing error between the workpiece and the lapping tool in the process of form lapping, is proposed. The mathematical model which the installing translation error influences on the workpiece surface shape error is established. The changing rule of the error is simulated through the calculating example of the paraboloid workpiece. The results indicate that the surface shape error of the workpiece is increasing with the increase of the installing translation error, it is also increasing gradually along the center point of the curve surface to the edge, and the influence is severer to the curve surface with great curvature than that of the small curvature when the translation error is the same.  相似文献   

19.
The paper introduces the performances of magnetostrictive actuators and its applications, discusses the design methods for the structure and internal magnetic circuit of a giant magnetostrictive actuator, and makes tests on the output displacement and force characteristics for an actuator using homemade magnetostrictive material. The experimental result shows that the actuator has satisfactory output precisions and ranges in transient and stable states, and can be used in lowfrequency vibration control system of precise equipment.  相似文献   

20.
The nonlinear dynamic model of spinning ballistic missiles is established during the first boosting phase of the missile. Based on the conventional backstepping sliding mode control and the assumption of a two time-scale separation of missile dynamics, a graded sliding mode controller is designed with two sub-sliding surfaces which have invariability to external disturbances and parameter perturbations, and a matrix which comprises three first order low pass filters is introduced to prevent "explosion of terms". Owing to the upper bounds of the uncertainties are difficult to obtain in advance, adaptive laws are introduced to estimate the values of the uncertainties in real-time. Eventually, the numerical simulation results given to show the proposed controller can ensure the steady flight of missiles.  相似文献   

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