New results on global output-feedback stabilization for nonlinear systems with unknown growth rate

Global adaptive output-feedback control for switched uncertain nonlinear systems

“…In what follows, we estimate the last two terms on the right-hand side of (12). Notice that by construction,L(t) ≥ 0, L(0) = 1 and therefore L(t) ≥ 1 for ∀t ≥ 0, which together with (6) yields…”

“…In recent years, the global output-feedback control has become an interesting topic in the field of nonlinear control theory, and therefore has attracted considerable attention [1,4,5,6,12,13,14,15]. As an important class of hybrid dynamical systems, switched nonlinear systems are usually encountered in practical applications, such as aircraft control systems, robot control systems, and networked control systems [2,8].…”

“…Based on such method, many interesting results on stability and stabilization of nonlinear system have been derived, see [5,6,10,12,14,15] and the references therein. In the non-switched case, when the growth rate of nonlinearities is unknown, how to design global output-feedback adaptive observer and controller becomes much more important.…”

“…Then more extensive results have been achieved in [6] by using double dynamic gains. Without additional conditions imposed on the system nonlinearities and control coefficients, global output stabilization problem was further investigated in [12] by introducing a distinct high-gain observer. In the switched case, the delicate construction of common Lyapunov function for all subsystems under arbitrary switchings is of great importance in global output-feedback stabilization.…”

Global output-feedback tracking for nonlinear cascade systems with unknown growth rate and control coefficients

“…Furthermore, when zero-dynamics exist and obey mild conditions, the tracking problem cannot be solved by trivially extending the corresponding results without zero-dynamics. As further investigation on [14][15][16] and the application of the analysis pattern in [2], this paper is devoted to the tracking control design for the following more general nonlinear systems with zero-dynamics and unknown time-varying control coefficients † : ⎧ ⎪ ⎪ ⎪ ⎪ ⎪ ⎨ ⎪ ⎪ ⎪ ⎪ ⎪ ⎩Ż = f 0 (t, Z, η, u), η i = g i (t)η i+1 + ψ i (t, Z, η, u), i = 1, 2, · · · , n − 1, η n = g n (t)u + ψ n (t, Z, η, u),…”