排序方式: 共有8条查询结果,搜索用时 15 毫秒
1
1.
2.
针对电液负载模拟系统存在多余力且该多余力严重影响系统加载精度与控制性能的问题,建立了系统各部分以及整个系统的数学模型.通过对数学模型的研究,分析了系统多余力的产生机理,并建立了系统多余力的传递函数.提出了前馈PID复合控制的方法,并对该方法进行了仿真分析和实验研究.在仿真分析中,通过对多余力消扰前、引入前馈控制消扰后及引入复合控制消扰后3种情况的比较,说明前馈PID复合控制能够有效抑制系统多余力.实验结果进一步验证了前馈PID复合控制的有效性,同时实验结果显示在运动换向时系统多余力将出现突变,为下一步的研究指明了方向. 相似文献
3.
4.
Polarization Changes of Partially Coherent Electromagnetic Vortex Beams Propagating in Turbulent Atmosphere 下载免费PDF全文
We investigate the polarization change of partially coherent electromagnetic vortex beams propagating in turbulent atmosphere. It is shown that the polarization of the beams will experience changes, and the changes of the polarization are dependent on the spatial coherence, topological charges of the beams, and the degree of polarization of the source plane and the atmospheric turbulence. The results obtained may have applications in space optical communication. 相似文献
5.
Based on vectorial Debye theory, the focusing properties of partially polarized vortex beam by high numerical aperture Fresnel zone plate are investigated. The effects of the numerical apertures of and the phase difference of binary phase Fresnel zone plates, the topological charge of vortex beam and the degree of polarization of incident beam on the intensity distribution and degree of coherence in the focal plane are investigated in detail. It is shown that elliptical light spots and the flat top beam can be obtained by selecting certain parameters. Studies of degree of coherence reveal that the degree of coherence between x and y components of the electric field, which is zero in the source plane, is improved in the focal plane for vortex beam, but it is hardly changed for the nonvortex beam. It is also proved that any two of the three electric field components Ex, Ey and Ez are completely coherent everywhere in the focal region if the incident light beam is linearly polarized. 相似文献
6.
7.
8.
基于德拜矢量积分理论,研究了随机电磁涡旋光束经过大数值孔径透镜之后的聚焦特性及透镜的数值孔径、入射光束的偏振度、拓扑荷以及横向相干长度对焦平面附近聚焦光束的光强分布和相干度的影响.结果表明:适当地选择相关参量,可在焦平面上得到椭圆形光斑的光强分布以及平顶光强分布.随机电磁涡旋光束在焦平面上同一点处两个相互垂直分量之间的相干度,不同两点处两个相同分量之间的相干度以及不同两点处两个相互垂直分量之间的相干度研究表明,入射光束的拓扑荷和横向相干长度对聚焦光束的相干性有着十分明显的影响. 相似文献
1