高功率激光器自动准直技术研究
文献类型：学位论文
| 作者 | 李红 |
| 文献子类 | 硕士 |
| 导师 | 朱健强 |
| 关键词 | 高功率激光驱动器 High power laser facility 自动准直 Automatic alignment 图像处理 Image processing 自动控制 Automatic control 最小二值化 Binarization 耦合矩阵 Coupling matrix |
| 其他题名 | Research of laser beam automatic-alignment system for high power laser facility |
| 英文摘要 | 以实现可用ICF（惯性约束聚变）为目标，世界上各国纷纷开展了对高功率激光驱动系统的研究。近年来高功率激光驱动器得到了飞速发展，光路路数不断增多、光束口径不断增大。由于对聚变输出能量的要求日益增长，放大器的数量及其他元器件的个数也在成倍地增长，增长的元器件数目及光路长度给准直过程带了更大的挑战。因光束通过元器件数目的增加，系统准直过程需要更长的时间，更高的精确度，因此高效性成为准直系统追求的目标之一。又因系统的整体空间是固定的，随着元器件数量的不断增多，留给准直系统的空间便相对减少，因此模块化成为准直系统所追求的目标之一。同时为满足未来高功率激光器对聚变能量更高的要求，智能化的自动准直系统仍是其追求的重要目标之一。如何确保激光光束能够高精度地穿过各个光学组件，最终精确地照射到微型靶丸上，并快速、准确地获得激光光束的真实误差信号，设计出一套高效的反馈补偿方式及控制程序，完成全系统光路的自动调整成为升级装置自动准直设计主要的技术难点。 本学位论文致力于高功率激光器自动准直技术的研究，主要目的是为高功率激光驱动器自动准直系统的快速、准确完成提供系统的、有效的保证，其主要内容如下： 1.提出一种新型的光斑定位、提取算法，实现对光斑目标的精确定位——为满足高功率激光驱动器光束自动准直的高精度和实时性要求，提出了一种快速高精度自动准直目标定位算法。首先利用变结构元广义数学形态学边缘检测算法在充分提取图像边缘细节信息的同时抑制图像噪声的影响，然后采用拉格朗日多项式插值算法对圆目标轮廓进行快速亚像素定位，最后利用最小二乘拟合以及几何形心拟合的方法实现图像中光斑目标中心的精确定位。该算法经实际验证，实验结果表明，主放输出光束近场准直准确度优于0.2%。 2.提出了一种基于光斑形状分析的自动准直方法，提高了准直系统的可靠性——为满足高功率激光装置光路自动准直系统的高精度要求，提出一种光束非垂直过孔状态下椭圆光斑的光斑差值快速调节法。首先，利用基于最小二乘法的椭圆拟合改进算法处理椭圆光斑，得到椭圆光斑长短轴的轴长，通过远场反射镜调节长短轴轴长差值以调节光斑形状，至长短轴轴长相近，获得规则的圆形光斑，然后，分析圆形光斑中心与基准位置的偏差值，将该差值转为闭环控制的步进电机调整步数，最终实现高功率激光装置光束的自准直。该算法应用在高功率激光装置光路自动准直系统中，结果表明，该算法的远场指向精度优于1μrad。 3.提出一种基于Jacobian矩阵的近远场串并行准直方式，大幅地降低了系统的准直时间——自动准直系统是维持高功率激光装置系统高效运行的重要子系统之一。结合以太网，设计出一套新型光路自动准直控制和检测方案。采用基于耦合矩阵的前馈补偿及图像Jacobian矩阵的近远场串并行准直方式，并在步进电机的控制策略中采用模糊控制算法，提高光束近远场图像的处理精度，大幅降低了系统的准直时间。该方案在某高功率激光装置实验平台上进行了实验验证。实验结果表明，该准直系统远场的平均调整误差为空间滤波器小孔直径0.44%，能够满足准直系统远场调整精度（小于小孔直径5%）的要求，准直时间由原有的30mins缩短至12mins左右。 4.准直系统软件的设计研究——系统地给出了高功率激光驱动器准直系统软件的设计理念。本部分首先给出了准直系统软件设计应遵循的原则和一般性的指标要求，之后给出了准直软件设计方法和实例分析。本部分的主要结论是系统地分析准直软件的设计方法、准直流程和实例。; In order to realize the ICF (inertial confinement fusion), many countries in the world have carried out studies on high power laser driver system. In recent years, driven by high power laser has been rapid development, the number of optical path and beam diameter is increasing. Because of the increasing demand for fusion output energy, the number of amplifiers and other components are growing exponentially, which brings greater challenges to the alignment process. Because of the increasing number of components through the beam, the system alignment process needs longer time and higher precision. Therefore, the efficiency becomes one of the goals pursued by the alignment system, and because the whole space of the system is fixed, the number of the components is increasing, so the space of the alignment system is reduced. Therefore, the modularization becomes one of the goals pursued by the alignment system. At the same time, intelligent automatic alignment system is still one of the most important targets in order to meet the higher fusion energy requirements of future high power lasers. How to ensure the laser beam passes through the optical components, accurately expose to micro target, and quickly and accurately obtain the true error signal of the laser beam, design a set of efficient feedback compensation and control program to complete the automatic alignment process of the entire system is the main technical difficulties in the system. This thesis is devoted to the study of high power laser automatic alignment technology, the main purpose is to provide effective guarantee system for high power laser driver automatic alignment system, and the main contents are as follows: 1.A new method of spot location and extraction is proposed to realize the accurate positioning of the target spot—to meet high accuracy and real-time requirements of automatic alignment system of the high power laser beam drive, a fast and high precision automatic collimation target localization algorithm is proposed. Firstly, variable structure generalized morphological edge detection algorithm is used to extract the image edge details and suppress the influence of image noise. Then the Lagrange polynomial interpolation algorithm is adapted to fast sub-pixel positioning round target outline. Finally by using the least squares fitting and geometric fitting method the image spot precise localization of target center is realized. The algorithm is actual certificated in the automatic alignment optical path of high power laser facility, The experimental results show that the alignment accuracy of near-field output beams is better than 0.2%. 2.An automatic alignment method based on spot shape analysis is presented to improve the reliability of the alignment system —In order to meet the high precision requirements of automatic alignment system of the high power laser device, a new method of elliptic light spot differential quick adjustment in the state of non-vertical is put forward. Firstly, the elliptical spot is processed by the ellipse fitting algorithm based on the least squares method to obtain the geometry parameter of the elliptical spot. The length of the long and short axis is adjusted by the far field mirror to obtain the regular circular spot, and then the deviation of the center of the circular spot and the reference position is analyzed, turning the deviation into steps of the closed-loop control stepping motor, and finally realizing the laser beam auto alignment of the high power laser device. The algorithm is applied to the automatic alignment system. The result shows that the far-field pointing accuracy of the algorithm is better than 1μrad. 3.A near-far field serial-parallel alignment method based on Jacobian matrix is proposed, greatly reducing the system alignment time—Alignment system is one of important systems to maintain high power laser facility running efficiently. Combined with Ethernet, a new type of optical path automatic alignment control and detection scheme is designed. The method of near-far field parallel alignment using feed forward compensation based on coupling matrix and Jacobian image matrix, introducing the local adaptive threshold ,binaryzation algorithm and the fuzzy control algorithm applied to the adjustment of the stepping motor, improves the processing precision of near-far field image, greatly reducing the alignment time of the system. The scheme has been verified successfully on a high power laser facility experiment platform. Experimental results show that the average far-field alignment error is less than 0.44% of spatial filter pinhole diameter, which meets the alignment system requirements（5% of spatial filter pinhole filter pinhole diameter），and alignment time is shortened from the original 30mins to 12mins. 4.Design and research of automatic alignment system software—the design concept of high power laser driver collimation system software is systematically given. Firstly this part presents the principles and general requirements that automatic alignment system software design should be follow, and then automatic alignment software design method and example analysis is given. The main conclusion of this section is to systematically analyze automatic alignment software design method, automatic alignment process and case analysis. |
| 学科主题 | 光学工程 |
| 源URL | [http://ir.siom.ac.cn/handle/181231/30987]  |
| 专题 | 中国科学院上海光学精密机械研究所 |
| 作者单位 | 中国科学院上海光学精密机械研究所 |
| 推荐引用方式 GB/T 7714 | 李红. 高功率激光器自动准直技术研究[D]. |
入库方式： OAI收割
来源：上海光学精密机械研究所
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