KMS of Xinjiang Astronomical Observatory, CAS
| 大口径射电望远镜天线伺服控制算法的研究 | |
| Alternative Title | The Study of Antenna Servo Control Algorithm for Large Aperture Radio Telescope |
李宁
| |
| Subtype | 硕士 |
| Thesis Advisor | 王娜 |
| 2017 | |
| Degree Grantor | 中国科学院大学 |
| Place of Conferral | 北京 |
| Degree Discipline | 天文技术与方法 |
| Keyword | 大口径天线 伺服系统 低频谐振 Ladrc 鲁棒性 |
| Abstract | 随着射电天文观测频率的增加，以及对深空中弱源观测的要求，大口径天线得到越来越多的应用，对天线指向精度及跟踪精度的要求也越来越高。而天线伺服控制性能是影响天线指向跟踪精度中一个重要的因素。 研究发现影响天线伺服控制性能的本质是天线运行过程中，除了天线刚度，内部和外部的扰动作用，使得天线的驱动力矩发生脉动，进而造成系统的低频谐振，使得控制系统的输出性能下降。而控制算法可以有效的减小低频谐振的危害。 目前存在两类算法：（1）非基于模型的控制算法。非基于模型的传 统PI(D)被大量应用于天线伺服控制系统。但随着对指向、定位精度要求的进一步提高，经典PI(D)控制器往往力不从心，尤其是在面临低频阵风干扰的复杂环境时，更难以使得系统满足更高精度的伺服要求。（2）基于模型和观测器的控制算法。虽然相较于传统PI(D)，其控制精度提高了，但是当面临系统内部参数的变化时，模型失效导致控制器的鲁棒性降低。 本论文分析了几种控制算法，结合射电望远镜天线的工况、控制目的及控制器设计原则，选取线性自抗扰控制（LADRC)算法，并应用于某35m天线方位轴位置环仿真。通过MATLAB中的Simulink，进行了时域和频域的仿真验证。 其中，时域下进行无扰动、扰动作用下阶跃响应和扰动作用下的斜坡响应；频域下，绘制两种算法下的Bode图，分析其稳定性和控制精度。 仿真结果表明，LADRC算法不仅拥有良好的动态性能-上升时间短，超调量小和到达稳态时间短，而且有较强的抗扰能力-相同扰动情况下，对扰动的抑制作用比传统的PI(D)高75%以上。 |
| Other Abstract | With the increasing observation frequency and to meet the need of observing weak sources in the deep space, the large aperture telescopes are widely applied, hence the accurate pointing and positioning become more and more important. The per¬formance of antenna servo control is one of the important factors that influence the pointing and positioning precision. In addition to the stiffness of the antenna, the internal and external disturbance, leading to the pulsed driving torque, which cause the so-called low frequency reso¬nance, limit the performance of antenna servo system. However, the algorithm could reduce its influence effectively. Currently there are mainly two kinds of algorithms: (1) Non-model-based control algorithm. Classical PI (D) controller which is not model based is widely used in antenna servo control system currently. However, PI (D) could not meet the higher requirement of pointing and positioning accuracy, especially under the condition of low-frequency wind disturbance. (2) Model-based and observer-based control algorithm. Comparing to the clas¬sical PI (D) controller, the control accuracy of model-based is improved. However, when the internal parameters of the system change, the robustness of the controller is reduced due to the failure of the model. Considering the environment condition of telescope and the design principles of controller, the author chose LADRC algorithm after investigating several methods, and this is applied to simulate the position loop of azimuth axis of a 35m antenna. We test the algorithm in the time-domain and frequency-domain by Simulink in MAT- LAB. The step responses with and without disturbance, and the ramp response with disturbance in the time-domain, as well as the Bode plot of the two algorithms in the frequency-domain are applied to analyze the stability and control accuracy. The simulations show that the LARDC algorithm not only own good dynamic performance which include short rising-time, small overshoot and short stability-time, but also has better anti-disturbance ability. The disturbance rejection is 75% higher than the traditional PI (D) under the same disturbance condition. |
| Language | 中文 |
| Document Type | 学位论文 |
| Identifier | http://ir.xao.ac.cn/handle/45760611-7/1711 |
| Collection | 研究生学位论文 射电天文研究室 |
| Affiliation | 中国科学院新疆天文台 |
| Recommended Citation GB/T 7714 | 李宁. 大口径射电望远镜天线伺服控制算法的研究[D]. 北京. 中国科学院大学,2017. |
| Files in This Item: | ||||||
| File Name/Size | DocType | Version | Access | License | ||
| 2017年硕士学位论文-李宁.pdf（3993KB） | 暂不开放 | CC BY-NC-SA | Application Full Text | |||
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