The performance of discrete linear time-varying control for l2 disturbance rejection

This paper extends the results of Zhang et.al. (1997) for linear periodically time-varying control to general linear time-varying (LTV) control. It is shown that linear time-invariant (LTI) control provides strictly better control performance than linear strictly time-varying control if l2 disturbance rejection of LTI plants is considered. The analysis is carried out in the frequency domain. This approach provides not only new results on disturbance rejection of LTV control but also some new insight into the properties of general LTV systems