“…Theorem 1: Consider the strict-feedback nonlinear system described by (1) with Assumptions 1-2. Consider the intermediate virtual control laws (18), (34), the actual control law (54), and the adaptive laws (19), (20), (35), (36), (55), and (56). For any ξ > 0, and bounded initial conditions satisfyinĝ ψ i (0) ≥ 0,Ξ i (0) ≥ 0 and V (0) ≤ ξ with ξ being any given positive constant, there exist design parameters c i , σ i , υ i , and τ i such that: i) The compact set Ω n × Ω 0 × Ω θ is an invariant set, namely, V (t) ≤ ξ for ∀t > 0, and hence all the signals in the closed-loop system are semi-globally uniformly ultimately bounded (SGUUB); ii) The output tracking error z 1 satisfies lim t→∞ |z 1 | ≤ √ 2Σ, where Σ > 0 is a constant that can be made arbitrarily small by properly selecting the design parameters.…”