天线伺服系统的快速辨识算法

A fast algorithm of system identification for antenna servo systems

中文关键词  系统辨识  欠阻尼二阶系统  阶跃响应  天线伺服  模型验证

英文关键词  System identification  second order damping system  step response  antenna system  model validation

中文摘要

      天线伺服控制系统在移动卫星通讯中起着关键性作用,其对象模型的品质直接影响天线伺服控制系统的设计与性能.本文针对天线伺服系统的建模问题提出一种基于系统阶跃响应的快速优化建模方法.利用这一结果,我们建立了0.9 米小口径天线伺服系统的二阶模型.进一步,我们讨论了基于系统伪随机响应谱密度函数的模型有效性验证方法和模型品质评价准则.并分别在频域和时域中将由本文方法及最小二乘法所得的模型与系统实际数据进行对比分析.本文辨识方法的优点是计算简单,易于工程应用,对系统阶次不敏感并且能较为精确地描述系统主谐振峰的特性,适用于实际工程中的参数在线整定.

英文摘要

      Antenna servo control systems play a key role in mobile satellite communication. The quality of plant models directly affects the design and performance of the control systems. This paper proposes a fast modelling method based on the systems’ step responses for the modeling problem of antenna servo systems. Using this method, we establish a second order model for a 0.9 m small-caliber antenna servo system. Based on the spectral density function of the system’s pseudorandom response, the validity of the model is studied and an evaluation criterion of the model quality is given. In the time domain and frequency domain, this model is compared with the experiment data and the models obtained by using the least squares identification method, respectively. The advantages of the proposed identification method are of simple calculation,ease for engineering application, insensitive to system’s order. Moreover, the proposed method can identify servo system’s resonant frequency quite accurately and is suitable for controller parameter online tuning of feedback systems.