Prescribed performance fuzzy output tracking control for time-varying delayed high-order nonlinear systems with unknown input dead zone

Finite-time prescribed performance tracking control for unknown time-varying delayed high-order nonlinear systems (HNSs) with unknown input dead zone is investigated in this paper. Fuzzy logical systems are employed to identify unknown uncertainties. An improved finite-time prescribed performance function is devised to ensure the error signal converges to any predefined residual set at any specified time. The output of unknown dead zone with high-order power u theta n(v(t)) is reconstructed as a friendly form, so that the real controller can be designed properly via adaptive estimation tactic. The time-varying delay is tackled by an improved Lyapunov-Krasovskii function. Moreover, the approximation errors and the conversion coefficient 1 psi(u) are estimated via the adaptive parameters. Finally, the simulations show that the error signal converges to the prescribed set within the settling time and the control performance can be pledged.