“…Since E k (t) is bounded for any iteration k, the two universal barrier functions as in (11) and (12) are bounded, hence (13) and (14) will always be met during operation. Furthermore, from the design of Ω zL, k , Ω zH, k , and k , in (15), (17), and (16), respectively, we see that, over t ∈ [T 1 , T], + (a 3 − a 1 )e −a 2 k < z e, k < 2 + ′ + e −a 2 k a 3 + e −a 5 k a 4 , which gives a prescribed performance range of the tracking error z e, k over the iteration domain.…”