共查询到20条相似文献,搜索用时 78 毫秒
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介绍了四象限跟踪传感器原理后, 分析了存在噪声和死区条件下的四象限探测器的光斑能量探测率、质心探测误差和光斑位移敏感度, 推导了此时四象限跟踪传感器跟踪误差的理论公式, 并通过实验证明了理论分析的正确性. 理论分析和实验的结果都表明, 在相同的噪声情况下, 质心探测误差和位移敏感度都随着光斑的高斯宽度与死区宽度之比减小而增大, 但是位移敏感度增大的趋势要小于质心探测误差增大的趋势, 它们共同作用的结果就导致了光斑的高斯宽度与死区宽度之比越大, 四象限跟踪探测器的跟踪误差越小. 相似文献
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数字闭环光纤陀螺引入的死区问题限制了其向更高性能惯性导航系统的应用。采用数学模型分析了数字闭环光纤陀螺死区的成因是反馈相关误差干扰,通过simulink仿真工具对死区现象进行了仿真,对比陀螺死区测试对模型进行了验证。以此为基础提出了电光合串扰造成死区的干扰模式,分析了干扰误差源的信号频域特征并使用频谱分析仪对受干扰的光功率信号进行了相关频点的测试,同时对比了干扰抑制后无死区的光功率信号相关频点的测试结果。通过抑制相关误差前后的测试结果对比,验证了与数字闭环反馈阶梯波相关的误差输入是死区形成的根本原因,除了电路交叉耦合之外,电路对光强的调制干扰也会造成死区问题。在采用针对干扰信号频率特性的退耦及PCB设计后,闭环光纤陀螺死区由0.2/h降低至0.02/h,满足系统应用需求。 相似文献
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针对广播式自动相关监视(ADS-B)报文的时间延迟对ADS-B/广域多点相关(WAM)数据关联跟踪精度的影响问题,在ADS-B时间延迟条件下对最近邻数据关联(NNDA)和概率数据关联(PDA)两种经典的数据关联方法的跟踪性能进行比较分析。采用MATLAB仿真计算存在ADS-B时间延迟时,ADS-B报告位置与跟踪预测值的平均马氏距离及关联结果的位置误差均方根,对比两种数据关联方法在上述两个统计平均值的关系。分析结果表明:存在ADS-B时间延迟时,PDA方法在跟踪误差和稳健性上优于NNDA方法,同时ADS-B时间延迟会增加跟踪测量误差。 相似文献
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光电跟踪系统计算机辅助控制实现 总被引:1,自引:1,他引:0
建立了基于数值微分的目标运动状态滤波预测模型,用s-函数实现了卡尔曼滤波预测算法。利用目标位置拟合方法给出角位置信息,并以此为观测信息通过卡尔曼滤波预测出当前角位置和角速度信息,将其引入跟踪控制系统中以克服脱靶量滞后问题,同时也实现了系统的等效复合控制。仿真结果表明,基于数值微分的模型适用于角度跟踪,滤波预测具有较好的鲁棒性。通过对两个不同等效正弦输入的验证,可知角位置合成精度对共轴跟踪影响较大,在脱靶量和跟踪架角位置采样匹配对应时,跟踪仿真精度较高,而对等效复合控制跟踪误差影响较小,输入信号角频率增大时误差增大。 相似文献
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Consider a simple locally finite hypergraph on a countable vertex set, where each edge represents one unit of load which should be distributed among the vertices defining the edge. An allocation of load is called balanced if load cannot be moved from a vertex to another that is carrying less load. We analyze the properties of balanced allocations of load. We extend the concept of balancedness from finite hypergraphs to their local weak limits in the sense of Benjamini and Schramm (Electron J Probab 6(23):13, 2001) and Aldous and Steele (in: Probability on discrete structures. Springer, Berlin, pp 1–72, 2004). To do this, we define a notion of unimodularity for hypergraphs which could be considered an extension of unimodularity in graphs. We give a variational formula for the balanced load distribution and, in particular, we characterize it in the special case of unimodular hypergraph Galton–Watson processes. Moreover, we prove the convergence of the maximum load under some conditions. Our work is an extension to hypergraphs of Anantharam and Salez (Ann Appl Probab 26(1):305–327, 2016), which considered load balancing in graphs, and is aimed at more comprehensively resolving conjectures of Hajek (IEEE Trans Inf Theory 36(6):1398–1414, 1990). 相似文献
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Zhihui Xiao Zuying Zhang Wei Guo 《International Journal of Infrared and Millimeter Waves》2000,21(7):1141-1151
A hot calibration load whose temperature is measured and controlled is described, and the measurement method of the microwave absorber reflectivity is also mentioned. In the end, two mathematical models are provided. The numerical results show obviously that the brightness temperature is the function of the angle of view, the contribution of the insulation layer can not be neglected. 相似文献
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通过对太阳能电池板内阻随光照强度变化和电池板输出功率随负载电阻变化的研究,分析了光照强度和负载电阻对输出功率的影响机制,得到电池板最佳输出功率的负载值. 相似文献
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The differential quadrature method (DQM) has been successfully used in a
variety of fields. Similar to the conventional point discrete methods such as the collocation
method and finite difference method, however, the DQM has some difficulty
in dealing with singular functions like the Dirac-delta function. In this paper, two
modifications are introduced to overcome the difficulty encountered in solving differential
equations with Dirac-delta functions by using the DQM. The moving point load
is work-equivalent to loads applied at all grid points and the governing equation is
numerically integrated before it is discretized in terms of the differential quadrature.
With these modifications, static behavior and forced vibration of beams under a stationary
or a moving point load are successfully analyzed by directly using the DQM.
It is demonstrated that the modified DQM can yield very accurate solutions. The compactness
and computational efficiency of the DQM are retained in solving the partial
differential equations with a time dependent Dirac-delta function. 相似文献
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Yu. A. Khon H. Zapolsky P. P. Kaminskii A. N. Ponomarev 《Physics of the Solid State》2018,60(7):1344-1350
The mechanism of dynamic instability of a solid surface under a load, determined by perturbations of the electron density and the change in the interatomic interaction, is considered. This instability is manifested upon the excitation of dynamic displacements of atoms in the surface layer, which can lead to formation of finite-lifetime structures in the form of waves with a large amplitude. Such structures were earlier observed experimentally on a stretched germanium (111) surface. 相似文献
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干式负载广泛应用于发电机组的性能测试与维护保养领域。为了提高其智能化水平,设计并实现了基于西门子S7-200 PLC的控制系统,其控制策略是先用穷举法找出功率总和等于功率设定值的档位组合,再根据干式负载的故障情况,从找出的档位组合中剔除那些因为故障而无法实现的档位组合,最后按照“需要操作的档位数量最少”、“优先选择动作次数最少的档位”这两个指标,从剩余的档位组合中挑选出一个最优值用于最终输出,从而实现了降低操作人员的工作负担、均衡接触器的动作次数和寿命、在突发故障时最大程度保证试验正常进行的目的。 相似文献
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贝壳作为典型的抗冲击生物材料,具有轻质、高强、高韧等优异性能。通过构建仿贝壳砖泥结构有限元模型,并对其在落锤冲击载荷下的动态响应进行数值模拟,分析了堆叠层数、冲击速度及锤头类型对仿贝壳砖泥结构能量吸收性能的影响。结果表明:5类堆叠层数下的仿贝壳砖泥结构的比吸能呈先增加后减小的变化趋势,并且在所设计的5类堆叠层数结构中,3层仿贝壳砖泥结构具有最大的比吸能,其值较比吸能最小的单层结构提高了10.8%;随着冲击速度的提升,结构载荷峰值及能量吸收均略有增大;相同锤径下,圆柱形锤头较半球形锤头更易穿透模型。 相似文献
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对确定的电源来讲,若负载为纯电阻且负载电阻等于电源内阻时,电源供给负载的功率最大即R=r时Pmax(ξ)2/4r这时称负载与电源匹配. 相似文献