Dynamic event-triggered adaptive output feedback control of uncertain nonlinear systems with intermittent observations

In this paper, the output feedback adaptive control problem of uncertain nonlinear system with event-sampled states is studied. Firstly, a novel intermittent-state observer is designed to estimate the unmeasurable states. Secondly, the nature of event-triggered makes the state signals discontinuous, rendering the traditional backstepping technique inapplicable as the derivatives of virtual control signals do not exist. To overcome this non-trivial obstacle, we consider the case without state-triggering in the previous n−1 steps of Lyapunov stability analysis, and reconstruct the actual controller by utilizing the triggered states signals in the last step. It can be demonstrated that all signals of the resulting closed-loop system are semi-globally uniformly ultimately bounded (SGUUB) under the derived event-triggered laws and the system performance can be improved by tuning design parameters properly. Simulation examples are shown to validate the efficacy of the proposed control scheme.