Fixed-Time Nonlinear Observer for a Class of Applicable Nonlinear Systems

This article addresses the challenge of creating fixed-time observers for a specific class of nonlinear systems, containing both matched and mismatched uncertainties. The class of nonlinear systems discussed in this paper includes many real-world nonlinear systems such as unmanned aerial vehicles, robot manipulators, and so on, which makes the proposed observer applicable to many practical nonlinear systems. According to fixed time stability theorem, it is proven that states of proposed observer will achieve to the real states in a fixed time. Fixed-time observers offer a key advantage over finite-time observers: their convergence time is guaranteed regardless of the system's initial state; it solely depends on the design parameters. Numerical simulations confirm the proposed observer's ability to accurately estimate system states.