/spl Hscr//sub 2/ tracking performance limitation under physical constraints

In this paper we investigate the best achievable /spl Hscr//sub 2/ tracking performance for a step reference signal under physical constraints such as control effort limitation and sampled-data control scheme. We here extend our previous results slightly and summarize the practical control performance limits based on the derived analytical closed form expressions, which consist of a term affected by the non-minimum phase zeros including the time-delay of the continuous-time plant and extra terms which are affected by physical constraints imposed such as control effort constraints and sampling.