Mixed domain analysis of MIMO dynamic interactions

In this paper, a mixed domain interpretation is given for the participation matrix, a MIMO complexity reduction strategy based upon gramians. It is shown that dominant dynamic interactions in stable MIMO linear systems can be captured using a time domain characterisation and, via Parseval, a frequency domain interpretation. The approach can be applied to stable continuous-time, as well as discrete-time MIMO systems. It provides support for decisions on plant model reduction, and consequently on controller structure selection and policy making. Moreover, the time-domain result is exploited to obtain a participation matrix estimate directly from input-output data.