Comparisons of Frequency Response Function Identification Methods Using Single Motion Data: Time- and Frequency-Domain Approaches

In this paper, frequency response function (FRF) identification methods using single point-to-point motion data for the fast and precise motion control of industrial servo systems are examined. The adaptation of controllers using an identified FRF is effective for maintaining the motion accuracy, even if plant parameters vary in the processing operation. However, it is difficult to achieve an accurate FRF from the motion data during repetitive motions with short time-intervals. In this study, a time-domain least squares method-based FRF identification method and a frequency-domain discrete Fourier transform-based FRF identification method were theoretically and experimentally evaluated, using a laboratory galvano scanner.