| 题名 | 激光通信系统精跟踪PID控制算法研究及实现 |
| 作者 | 曹洪瑞 |
| 学位类别 | 硕士 |
| 答辩日期 | 2015 |
| 授予单位 | 中国科学院大学 |
| 导师 | 张淑梅 |
| 关键词 | 激光通信 ATP FSM PID 自适应 模糊 DSP Builder |
| 其他题名 | Research and implementation of PID control algorithm for laser communication fine tracking system |
| 学位专业 | 机械工程 |
| 中文摘要 | 随着通信技术的发展和通信传输数据量的不断增加，当前军事领域主要采用的微波技术已经不能满足人们对信息传输速率和带宽的要求，光纤通信技术成为人们的首选。但部分地区由于地貌、地势等原因不宜铺设光缆，需要一种可靠的无线通信技术来解决困难，基于这些情况激光通信技术应运而生。相比于传统的通信技术，自由空间激光通信具有通信容量大、保密性高、机动性好、抗电磁干扰能力强、建造和维护经费低等优势。激光通信技术以其具有的种种优点被认为是未来实现高速大容量通信的最佳方案。 激光链路的快速建立及稳定保持是实现高速率、高可靠性激光通信的保障和前提，这需要由捕获、跟踪、瞄准（Acquisition，Tracking and Pointing，ATP）系统来实现。在星地、星间、舰船、岸舰等激光通信过程中，ATP过程受作用距离、大气湍流扰动及其他外界环境因素的影响，很难实现快速、高精度的跟踪捕获及激光通信的链路建立。 为保证通信链路的持续可靠维持并达到更高的跟踪精度，空间激光通信系统多采用一级粗跟踪加二级精跟踪的复合轴结构形式。精跟踪系统具有响应速度快、谐振频率高、动态滞后小等特点，其较小的工作范围由主轴系统予以补偿，两者相结合可实现快速大范围高精度跟踪。二级控制系统通常使用FSM（Fast Steering Mirror，FSM）以获得更高的控制带宽。 PID控制是FSM控制最普遍应用的控制方式，其结构简单、参数易于调节，能够获得良好的控制效果。但随着系统控制品质要求的不断提高，常规PID控制需要精确数学模型、不适应非线性控制过程等缺点也逐渐显现出来，实际控制过程中，系统具有的纯滞后或非线性耦合、时变的特点导致结构和参数出现不确定性，无法获得精确数学模型，加之各种外部扰动的存在，常规PID控制不能获得理想的控制效果。 本文针对激光通信系统对ATP的高精度需求，提出自适应PID和模糊PID两种FSM控制算法，能够克服传统PID控制的响应时间长、超调量大、带宽低等缺点，实现快速响应的高精度精跟踪子系统。本文分别对两种控制算法搭建仿真模型进行分析，并将其转换成CCS程序通过以DSP2812为核心的控制系统进行桌面跟踪实验，并将搭建的系统模型转化为适用于FPGA中的VHDL文件，从硬件层面对所设计的两种控制算法进行验证。 实验结果表明，当使用自适应PID控制器时，当外界有较大扰动时系统的抗干扰性能有较大改善；使用模糊PID控制器时，当被控对象发生变化时依然具有较好的鲁棒性。应用两种控制算法均能实现2微弧度的跟踪精度。用FSM作为被控对象研究设计控制算法来抑制ATP过程中各种扰动造成的影响，保证链路的快速建立和稳定性，是发展自由空间激光通信技术不可缺少的，高精度快速控制算法的研究及实现为激光通信中进行高精度跟踪提供了理论支持和实际系统应用的经验，可以为激光通信精跟踪技术的发展提供参考，具有重要的研究意义。 |
| 英文摘要 | With the continuous improvement of communication technology and the information transmission between terminals is becoming more and more abundant. Due to the limitation of communication bandwidth, in the field of military, microwave technology is unable to meet the requirements. Optical fiber is becoming popular, in some areas, due to the topography, terrain and other reasons it is unsuited to lay fiber optic cable, then we need a reliable wireless communication technology to solve this problem. Based on these conditions, laser communication technology came into being. Compared with traditional communication technologies, the free space laser communication has the advantages of large communication capacity, high security, well mobility, strong anti electromagnetic interference ability, construction and maintenance funds and so on. Laser communication technology is considered as the best solution for the future to achieve high speed and large capacity communication in the future. The fast establishment and stable maintenance of laser link is the guarantee and premise of realizing high speed and high reliability laser communication. This need the capture, tracking, targeting (Tracking, and, Pointing, Acquisition, ATP) system to realize. In the process of laser communication, such as star to star, ship to shore, the ATP process is affected by the action distance, atmospheric turbulence and other environmental factors.In order to ensure the continuous and reliable communication link to maintain and achieve higher tracking accuracy, the space laser communication system uses composite axis structure including one level coarse tracking and second level fine tracking. The fine tracking system has the advantages of high frequency, high response speed, small dynamic lag error and so on, making up the shortages of the main shaft system, and the disadvantages of small working range are compensated by the main shaft system. To obtain a higher control bandwidth The second level control system usually used Fast Steering Mirror (FSM). PID control is the most widely used FSM control mode, its structure is simple, is easy to adjust the parameters to get a good control effect. However, with the continuous improvement requirements of control system’s quality, the conventional PID control’s shortcoming such as need accurate mathematical model and improper to nonlinear control process. The practical system has the characteristics of the structure and parameters’ uncertainty, the pure delay, nonlinear coupling, time-varying, and various external disturbances, the conventional PID control can’t get ideal control effect. In order to meet the high accuracy requirement of ATP, this paper proposes the adaptive PID and fuzzy PID control algorithm. The two FSM control algorithms are able to overcome the disadvantages of the traditional PID control system, such as couldn’t adjust the parameters, used in nonlinear systems. We analysis two kinds of control algorithms, built the simulation model and converted it into CCS program, and the DSP2812 is used as the core of the desktop tracking experiments, transformed the system model into VHDL file in FPGA, and verified the two control algorithms in hardware layer. The experimental results show that when the disturbance is large, the anti disturbance performance of the system is greatly improved when used the adaptive PID controller. When using fuzzy PID controller, it still has good robustness when the object is changed. Two control algorithms are applied to achieve the tracking accuracy of 2 micro-radian. As the object of the research and design of the controlled object, fast mirror is used to suppress the influence of various disturbances in the process of ATP. The research and implementation of high precision and fast control algorithm can provide theoretical support and practical experience for high precision tracking in laser communication. It can provide reference for the development of laser communication and tracking technology. |
| 语种 | 中文 |
| 公开日期 | 2016-05-03 |
| 内容类型 | 学位论文 |
| 源URL | [http://ir.ciomp.ac.cn/handle/181722/49289]  |
| 专题 | 长春光学精密机械与物理研究所_中科院长春光机所知识产出 |
| 推荐引用方式 GB/T 7714 | 曹洪瑞. 激光通信系统精跟踪PID控制算法研究及实现[D]. 中国科学院大学. 2015. |
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