Robust indirect adaptive control combined with frequency domain methods and its application to robot

The authors propose combining indirect adaptive control, which has wide applications, with frequency-domain methods and show the scheme´s application to a robot. In order to identify the wide-frequency response of a controlled system from the input-output data accurately, a multiple recursive identification method, combined with the decimation technique, is presented. The control parameters of a two-degrees-of-freedom PID control system, are determined by using the model matching method in the cutoff frequency region on the basis of the identified frequency response. Adaptive control based on frequency-domain methods can be widely applied to controlled systems, including not only minimum-phase systems but also nonminimum phase systems, even at the fast sampling rate. The superior features of the adaptive control scheme are summarized and its effectiveness is shown through experiments using an industrial robot