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基于光电跟踪伺服系统全数字化的特点,提出了一种新型频率特性测试方法,并对该方法所使用的激励信号、数据采集方式、幅值和相位提取算法、模型辨识算法进行了研究。利用数字运动控制器产生离散的正弦扫频信号,同时采集响应信号并存储在磁盘上,对其进行测试后,将文件导入Matlab进行数据预处理;然后,采用相关分析方法计算输入输出信号的幅度比和相位差;最后,利用递阶辨识算法将测量得到的数据转化为高精度的传递函数。实验结果表明,测试信号基本可以覆盖伺服控制系统的频带宽度,在系统的中频段可以获得幅度±0.5 dB和相位±1°的辨识精度,在高频段也可以使用双二节滤波器拟合出机械谐振频率,证明了该方法的有效性和实用性。
Based on the characteristics of full digital tracking servo system, a new frequency characteristic test method is proposed. The excitation signal, data acquisition method, amplitude and phase extraction algorithm and model identification algorithm are studied. Digital motion controller is used to generate discrete sine sweep signal, meanwhile the response signal is collected and stored on the disk. After testing, the file is imported into Matlab for data preprocessing. Then the correlation analysis method is used to calculate the amplitude of the input and output signals Ratio and phase difference; Finally, the use of hierarchical identification algorithm will measure the data into high-precision transfer function. The experimental results show that the test signal can basically cover the bandwidth of the servo control system, and the identification accuracy of ± 0.5 dB and phase ± 1 ° can be obtained in the middle frequency range of the system. The high-frequency range can also be fitted with the double two-stage filter The mechanical resonance frequency proves the validity and practicability of this method.