KMS of Xinjiang Astronomical Observatory, CAS
| 轨道不平度测量与主动面控制系统研究 | |
| Alternative Title | Track Irregularity Measurement and Active Surface Control System |
刘璇
| |
| Subtype | 硕士 |
| Thesis Advisor | 艾力·玉苏甫 |
| 2018-06 | |
| Degree Grantor | 中国科学院大学 |
| Place of Conferral | 北京 |
| Degree Name | 理学硕士 |
| Degree Discipline | 天文技术与方法 |
| Keyword | 轨道不平度 指向模型 主动面系统 POWERLINK |
| Abstract | 随着射电天文这门学科的发展，大口径高精度射电望远镜在这一领域发挥着重要作用，面型精度和指向精度是衡量天线性能的重要指标。但是随着望远镜的口径的增大，其结构上会产生一定的变形，使反射面的精度下降。为了满足高频波段的天线效率，采用主反射面主动调整技术，调整天线面板位置，满足不同方位/俯仰角下，天线的效率最大化。 本文研究方向之一是，分析轨道不平整度对天线的指向偏差的影响，建立基于轨道不平度的指向修正模型。以NSRT（NanShan Radio Telescope）为研究对象，利用蔡司水准仪测得天线轨道面的高差数据，将测得的散点数据拟合成一个曲线。根据两条垂直的直径确定轨道面的法向量理论，得到天线指向的理论偏差角。采用框式水平仪测得天线二层平台的倾斜量，计算出天线的实际指向偏差。将理论偏差角与实际指向偏差进行相关性比较，发现二者相关系数达到0.7，这表明轨道不平整度是影响天线指向偏差的一个因素之一。依据软件校正方法，将轨道不平整度作为指向偏差模型的系数项，建立相应的系数修正模型。根据十字扫描法测得天线在已知源的指向偏差数据，通过最小二乘法确定模型的各项系数，得到基于轨道不平度的修正模型。对比不同的修正模型，发现本文的模型能提高指向精度，为QTT（QiTai Telescope）指向校正提供一定理论基础。 本文的另一个研究方向是，研究大口径射电望远镜的主反射面多节点控制系统，分析现场总线在主反射面控制系统应用中的优劣，为QTT主动面多节点控制系统设计提供理论基础。对比RS-485、POWERLINK、EtherCAT三种不同种类的总线技术的特点，并设计了基于这三种总线的QTT主动面控制系统网络。后续采用技术开源，网络实时性较高的POWERLINK技术作为实验对象，搭建一个局部的非实时通信系统，从而分析该技术的工作原理。实验采用两个普通PC作为网络的主从节点，设置两个节点的对象字典映射关系和数据传输格式，在本地存储节点的传输数据。采用Wireshark对POWERLINK协议帧进行捕捉分析，实现通过数据帧的状态信息来进行故障诊断，计算本地存储的数据误码率，同时对该系统的周期进行测试。 |
| Other Abstract | With the development of the radio astronomy discipline, large diameter high-precision radio telescopes play an important role in this field, shape accuracy and pointing accu racy are important indicators for measuring antenna performance. However, with the increase of the diameter of the telescope,a certain deformation wil occur in its struc ture, which will reduce the accuracy of the reflecting surface. In order to meet the antenna efficiency in the high frequency band, the main reflector real-time adjustment technology is adopted to adjust the position of the antenna panel to meet the different azimuth/elevation angles, and the efficiency of the antenna is maximized. One of the research directions in this thesis is to analyze the influence of the trackir-regularity on the pointing deviation of the antenna, establish a pointing correction model based on the track irmegularity. Using NSRT(NanShan Radio Telescope) as the researchobject, the ZEISS level instrument was used to measure the height difference data of the antenna orbital surface, and the measured scatter data was fitted into a closed curved surface circle. The normal vector theory of the orbital surface is determined based ontwo perpendicular diameters, and the theoretical deviation angle of the antenna direc tion is obtained. The tilt of the antenna platform on the second floor was measured using a box level and the actual pointing deviation of the antenna was calculated. The correlation between the theoretical deviation and the actual pointing deviation is compared. It is found that the correlation coeficient reaches 0.7, indicating that the track irregularity is one of the factors affecting the antenna pointing deviation. According to the software correction method, the track irregularity is used as the coefficient item of the pointing deviation model, and a corresponding coefficient correction model is established. According to the cross scanning, the data of the pointing deviation of theantenna in the known source are measured, and the coefficients of the model are deter mined by the least squares method. The modified model based on the track irregularity is obtained. Compared with different modified models, we find that the model can im prove the pointing accuracy and provide a theoretical basis for QTT(QiTai Telescope) pointing correction. Another research direction of this paper is to study the main reflector multi-node control system of the large-caliber radio telescope and analyze the advantages and disadvantages of the field bus in main reflector control system are analyzed, which provides a theoretical basis for the design of QTT active multi-node control system. Comparing the characteristics of three different types of bus technologies: RS-485, POWERLINK, and EtherCAT,a QTT active surface control system network based on these three buses was designed. Followed by the open-source technology, POWERLINK technology with high real-time network as the experimental object, to build a local non-real-time communication system, thus analyzing the working principle of the technology. The experiment adopts two ordinary PCs as the master and slave nodes of the network, set theobject dictionary mapping relationship and data transmission format of the two nodes, and transmit data in the local storage node. Wireshark is used to capture and analyze the POWERLINK protocol frame, to implement fault diagnosis through the status infomation of the data frame, to calculate the bit error rate of the local storage data, and to test the cycle of the system at the time. |
| Pages | 76 |
| Language | 中文 |
| Document Type | 学位论文 |
| Identifier | http://ir.xao.ac.cn/handle/45760611-7/2480 |
| Collection | 研究生学位论文 |
| Affiliation | 中国科学院新疆天文台 |
| First Author Affilication | Xinjiang Astronomical Observatory, Chinese Academy of Sciences |
| Recommended Citation GB/T 7714 | 刘璇. 轨道不平度测量与主动面控制系统研究[D]. 北京. 中国科学院大学,2018. |
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| 学位论文-刘璇.pdf（15342KB） | 学位论文 | 暂不开放 | CC BY-NC-SA | Application Full Text | ||
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