中国科学院 长春光学精密机械与物理研究所，吉林长春130033
自适应光学技术可以对大气湍流造成的波前误差进行实时校正，是实现大型地基望远镜高分辨率成像的关键技术。随着望远镜口径不断增大，自适应光学系统的校正单元数达到千单元量级。首先从自动控制角度建立了自适应光学系统各电控环节的等效模型，分析了系统延时对控制环节性能的影响。然后介绍了自适应光学电控环节中高压驱动系统的设计问题，从自动控制角度分析了自适应光学系统对高压放大器闭环带宽的需求，给出了分析结果。最后报道了千单元级自适应光学高压驱动系统的集成和测试工作。实验结果表明：本文所设计的高压放大器可以实现120 V输出，-3 dB带宽达到5 000 Hz，所设计的高压驱动系统经过集成后，利用湍流屏等效模拟60 Hz格林伍德频率，校正后的波前残差均值为0.16λ，可以实现千单元级压电变形镜的校正控制。
自适应光学 望远镜 自动控制 高压放大器 adaptive optics telescopes automatic controls high-voltage amplifiers 光学 精密工程
2023, 31(17): 2493
Author Affiliations
Abstract
1 Department of Physics, University of Oxford, Parks Road, Oxford OX1 3PU, UK
2 Laboratory for Laser Energetics, University of Rochester, 250 E. River Rd, Rochester, NY 14623, USA
3 Department of Physics, University of Nevada, Reno, NV89557, USA
4 Department of Astronomy and Astrophysics, University of Chicago, 5640 S. Ellis Ave, Chicago, IL 60637, USA
Magnetic field measurements in turbulent plasmas are often difficult to perform. Here we show that for
kG magnetic fields, a time-resolved Faraday rotation measurement can be made at the OMEGA laser facility. This diagnostic has been implemented using the Thomson scattering probe beam and the resultant path-integrated magnetic field has been compared with that of proton radiography. Accurate measurement of magnetic fields is essential for satisfying the scientific goals of many current laser–plasma experiments.
High Power Laser Science and Engineering
2018, 6(3): 03000e49
国防科学技术大学 电子科学与工程学院, 湖南 长沙 410073
提出一种改进的参数优化局部一维时域有限差分(LOD-FDTD)方法, 该方法将时间步长等分成3步, 沿坐标方向加上色散控制因子, 以降低数值色散误差。本文首先证明改进方法的稳定性, 并分析其数值色散误差。结果表明改进方法的数值色散误差小于传统的LOD-FDTD方法。
局部一维时域有限差分 色散控制因子 稳定性 数值色散 CFL条件数 Locally One-Dimensional Finite-Difference Time-Dom dispersion controls parameters stability numerical dispersion Courant Friedrich Lewy(CFL) limit 太赫兹科学与电子信息学报
2017, 15(4): 652
Author Affiliations
Abstract
1 EIED Department, Thapar University, Patiala, India
2 CSED Department, Global College of Engineering, Khanpur Kui, India
3 Chief Scientist, CSIO-CSIR, Chandigarh, India
People's working capability is badly affected when they suffer an amputated arm. Artificial replacements with prosthetic devices to get a satisfactory level of performance for essential functions with the currently available prosthetic technology are very difficult. Myoelectric arm prostheses are becoming popular because they are operated by a natural contraction of intact muscles. Hence, SEMG based artificial arm was fabricated. The system consists of different electronic and mechanical assemblies for operation of hand utilizing microcontroller in order to have minimum signal loss during its processing. With the help of relay switching connected to low power DC motor, system is capable of opening and closing of grip according to individual wish.
SEMG electrodes variable gripping myoelectric controls electronic interface signals processing Journal of Innovative Optical Health Sciences
2016, 9(6): 1650023
上海交通大学 机械与动力工程学院, 上海 200240
为了实现直线电机精密定位平台的位置和速度的轨迹跟踪控制, 本文基于内模控制(IMC)的基本原理, 在直线电机精密定位平台参数辨识的基础上, 设计了定位平台速度环的模型状态反馈(MSF)控制器和基于位置环PID和速度环MSF的级联控制器。将PID/MSF级联控制器与速度/加速度前馈控制(VFC/AFC)相结合, 构成了PID/MSF+VFC/AFC的复合轨迹跟踪控制器。该复合轨迹跟踪控制器通过整定速度前馈的增益来改善位置环偏差控制的跟踪滞后现象和动态响应, 增加控制系统的稳定性和伺服精度; 通过整定加速度前馈的增益在不减小级联控制器位置环增益的前提下, 减小速度前馈带来的超调量, 提高轨迹跟踪精度。基于MATLAB/dSPACE实时仿真控制平台, 实现了某直线电机平台的轨迹跟踪控制。仿真和实验结果表明, 该轨迹跟踪控制器的轨迹跟踪精度为±0.028 mm, 定位精度为±4 μm, 满足直线电机精密定位平台轨迹跟踪控制的要求。
永磁同步直线电机 模型状态反馈 速度/加速度前馈 硬件在回路仿真 Permanent-magnet Synchronous Linear Motor (PMSLM) Model State Feedback(MSF) Velocity/Acceleration Feedforward controls(VFC/AFC MATLAB/dSPACE MATLAB/dSPACE Hardware in the Loop Simulation (HILS)
电子科技大学光电信息学院, 四川 成都 610054
为获得一个优化的全光开关结构，在光子晶体90°弯曲波导的基础上，进一步改进光子晶体结构，并在其中加入克尔(Kerr)型非线性介质柱，得到了非线性光子晶体全光开关结构。通过时域有限差分(FDTD)法数值分析表明，该开关结构能够实现的带宽大约为50 nm，消光比大于40 dB，阈值功率密度约为5.2 W/μm。同时，该结构还可以实现基本的逻辑功能。
光学器件 光子晶体 光开关 非线性 光控制光 光学学报
2012, 32(10): 1016003
