共查询到19条相似文献,搜索用时 234 毫秒
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笔者将电场测试集成微系统应用于安全领域中的近场测试中.通过对电容理论的扩展以及对不同类型电容模型的理论分析,证实了其原理的可行性在对内交叉电极和螺旋型电极比较的基础上,设计选用了有良好效果特性的螺旋型电极.结合微处理器设计了电场测试集成微系统,并在空气介质和水介质中进行了近场探测实验.当有物体靠近电极时,会影响电极间的电场环境参数,输出测试电压值相应地发生变化.靶场实验结果也证明了该测试系统的可行性. 相似文献
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针对工程中最优单故障序贯测试难以隔离的多故障问题,利用Grunberg等人提出的多故障模糊组的概念,以最优单故障测试策略为基础,构造了一种多故障假设下的序贯测试算法.该算法以多故障状态集的最小碰集作为生成最优单故障策略的故障状态,生成最优单故障策略;以诊断决策树中各叶节点的多故障状态集为评判标准,确定系统的状态,完成多故障假设下的系统故障诊断;与连续使用单故障策略的方法相比,该方法提高了测试效率.以某型机载电子设备为例给出算例分析,验证了该算法隔离多故障的有效性. 相似文献
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光纤陀螺是20世纪70年代发展起来的一种新型惯性仪器,由于具有精度高、抗干扰能力强、预热时间短等一系列优点,在各个领域得到了广泛的应用。而要保证光纤陀螺的测试精度,一套高精度的测试系统是必不可少的。论文针对模拟光纤陀螺进行测试系统设计,以往采用较多的测试方法为:首先对信号进行A/D转换,再利用计算机进行数字信号采集;但由于AD转换存在精度低及连续性差等缺点,大大限制了测试系统的精度。基于这一方面考虑,论文中设计了一种简易的高精度光纤陀螺多路测试系统,直接对输出的模拟信号进行采集,再利用采集到的电压信号进行解算,得到角速度值。在组建完整套测试系统后,对设计的测试系统进行了试验验证及精度标定,试验结果表明,该测试系统具有较高的精度,完全可以满足中低精度模拟光纤陀螺的测试要求。 相似文献
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虚拟仪器在汽车数据采集系统中的应用 总被引:1,自引:0,他引:1
汽车试验设备是汽车性能测试的硬件基础,传统的汽车试验设备由于存在价格昂贵、功能单一、安装不便、功能扩展和升级困难、对温度、工况等要求严格,导致试验成本提高、试验数据不精确等问题.虚拟仪器(Virtual instrument,简称VI)设计思想的提出,恰恰可以很好地解决这些问题,用户可以根据自身需求设计自己的仪器系统,充分利用计算机技术来实现和扩展传统仪器的功能.本文重点介绍了基于虚拟仪器的数据采集系统的软件设计思想和方法. 相似文献
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基于性能参数检测与外部测试的测试性探讨 总被引:1,自引:1,他引:0
测试性是现代大型复杂工程设备设计的一项重要内容,测试性设计是改善其系统测试性能和故障诊断能力的有效途径.测试性的设计思想和诊断策略多是建立在机内测试(BIT)和故障率分析的基础之上的,针对以机械系统为主设备的测试性研究才刚刚起步.本文在分析电子设备和以机械系统为主设备各自结构特点的基础上,指出以往的测试性理论和方法不适用于以机械系统为主的设备,提出了基于性能参数检测与外部测试的测试性研究思想,确立了通过固有测试性设计、以外部测试为主进行故障诊断等方法来改善系统测试性的策略,找出了适用于机械系统的主要测试性表征参量. 相似文献
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Zhusheng Pan Liudong Xing Yuchang Mo 《Quality and Reliability Engineering International》2017,33(8):1957-1967
As an efficient data structure for representation and manipulation of Boolean functions, binary decision diagrams (BDDs) have been applied to network reliability analysis. However, most of the existing BDD methods on network reliability analysis have assumed perfectly reliable vertices, which is often not true for real‐world networks where the vertices can fail because of factors such as limited resources (eg, power and memory) or harsh operating environments. Extensions have been made to the existing BDD methods (particularly, edge expansion diagram and boundary set–based methods) to address imperfect vertices. But these extended methods have various constraints leading to problems in accuracy or space efficiency. To overcome these constraints, in this paper, we propose a new BDD‐based algorithm called ordered BDD dependency test for K‐terminal network reliability analysis considering both edge and vertex failures. Based on a newly defined concept “dependency set”, the proposed algorithm can accurately compute the reliability of networks with imperfect vertices. In addition, the proposed algorithm has no restrictions on the starting vertex for the BDD model construction. Comprehensive examples and experiments are provided to show effectiveness of the proposed approach. 相似文献
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《Circuits, Devices & Systems, IET》2008,2(5):429-438
An efficient architecture with the fast algorithm for MPEG-4 shape coding is proposed. The authors apply the fast shape coding algorithm, with contour-based binary motion estimation (CBBME), which is based on the properties of a boundary mask. By using the block-matching motion estimation and the extended approach on centre-biased motion vector distribution with shrinking of the search range, a large number of search points in BME can be skipped. Based on this algorithm, a dedicated architecture design using the proposed CBBME algorithm is developed. With certain optimisation and design considerations, the memory access and processing cycles can be reduced. The average number of clock cycles for the processing of one binary alpha block is only 1708, which is only 56% of the previous design. In addition, a prototyping chip for shape coding is implemented and verified. The die area is 2.4 x 2.4 mm2 with TSMC 0.18 μm CMOS technology and the maximum clock frequency is 53 MHz. 相似文献
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To explore and reduce the nonlinear error and temperature dependency of fiber-optic gyroscope (FOG) scale factor, a scale factor modeling method based on temperature is presented in this paper. A hyperbolic curve fitting is proposed according to the characteristic of scale factor under stable temperature at first. Compared to traditional modeling methods, it shows that a higher precision model of scale factor can be obtained. Then the influence of temperature on scale factor is analyzed and then the hyperbolic curve fitting method is extended based on temperature, making it possible to work over the whole potential temperature range of the FOG without degrading the performance. This paper also provides the experimental and verification results. It can be seen that a high precision model of scale factor has been established, the temperature dependency of scale factor has been reduced effectively, and the error due to environment temperature is reduced by one order at least. 相似文献
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Hafner C Xudong C Smajic J Vahldieck R 《Journal of the Optical Society of America. A, Optics, image science, and vision》2007,24(4):1177-1188
Seven different stochastic binary optimizers--based on the concepts of genetic algorithms and evolutionary strategies--are developed, applied to determine defect locations in several photonic crystal structures that serve as test cases, and compared by extensive statistical analysis. In addition to the stochastic optimizers, a quasi-deterministic optimizer based on an algorithm inspired by hill-climbing algorithms was implemented. The test cases include the prominent 90 degrees photonic crystal waveguide bend and a photonic crystal power divider. The analysis of the results shows that many different photonic crystal structures with high transmission may be found for any operating frequency. All of the eight optimizers outperform standard codes-because they maintain an incomplete fitness table-and find the global optima with a high probability even when the number of fitness evaluations is much smaller than the number of potential solutions contained in the discrete search space. Based on the incomplete fitness table, an algorithm to estimate bit-fitness values is presented. The bit-fitness values are then used to improve the performance of some algorithms. The four best algorithms-an extended microgenetic algorithm, two mutation-based algorithms, and the quasi-deterministic algorithm inspired by hill-climbing algorithms-are considered to be of high value for the optimization of defects in photonic crystals and for similar binary optimization problems. 相似文献
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针对结构与无限大声场的声振耦合系统中结构的双材料拓扑优化问题进行了研究。采用有限元与边界元方法分别对结构和声场进行离散。基于分段常数水平集(piecewise constant level set,PCLS)方法,构造了结构的刚度阵、质量阵与阻尼阵。优化目标选为最小化结构指定位置的振幅平方,采用伴随变量法进行灵敏度分析。引入二次罚函数方法来实现体积约束,基于灵敏度信息对优化参数进行重新定义,克服了参数的问题依赖性。数值结果表明优化设计可以显著降低结构的振幅,证实了优化方法的有效性。不同算例下体积约束在相同优化参数下均得到很好满足,说明了重新定义参数的优越性。 相似文献
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提出了一种基于波束空间的改进投影子空间正交性测试算法,以克服投影子空间正交测试(Test of Orthogonality of Projected Subspace,TOPS)算法在低信噪比时容易出现伪峰的缺点。通过对TOPS算法中的正交性测试矩阵添加对角修正矩阵,并利用波束空间方法对阵元接收数据进行预处理,从而实现对宽带信号的波达方向估计。仿真结果表明,文中所提出算法与TOPS算法相比,能够抑制波束指向范围内的伪峰,并能提高分辨概率和减少运算量,是一种具有应用前景的新算法。 相似文献
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针对中国缺少T800级复合材料螺栓连接设计参数的问题,发展一种综合连续损伤力学(CDM)和工程算法的单剪连接强度估算策略,以替代试验,降低研究周期和成本。在该强度估算策略中,首先建立试件的CDM有限元模型,通过数值模拟得到单剪螺栓连接的设计参数,包括单剪挤压强度修正系数、无缺口层合板拉伸强度和应力集中减缓因子等。随后根据上述参数,建立工程算法,估算复合材料单剪螺栓连接的最终挤压强度。结果表明:通过该策略得到的T800级复合材料螺栓连接设计参数和强度估算结果与试验结果有较好的一致性,说明该强度估算策略的可行性。 相似文献
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目的 改善包装印刷机器的控制性能,减少包装印刷机器所用传感器数量和电机控制系统成本,减小包装印刷机械装置故障率和电机体积,针对传统扩展卡尔曼滤波算法中模型可能不匹配实际工况的问题,提出一种自适应多模型无感控制策略。方法 基于传统扩展卡尔曼滤波,引入多模型,在输入环节依靠状态转移概率矩阵实现多个模型间的交互,并借助隐马尔可夫模型,设计多模型的状态序列和观测序列,将观测得到的矩阵对多模型交互环节的状态转移概率矩阵进行迭代更新,提高模型面对环境扰动时的匹配程度。结果 Matlab/Simulink仿真结果表明,改进后的算法使转速的估计精度得到显著提升,同时在面对环境扰动时,其抗扰动能力显著提高。结论 与传统扩展卡尔曼滤波算法相比,改进算法提高了系统控制精度,提高了动态性能和鲁棒性,改进后算法更适合应用于包装印刷机械。 相似文献