Uniformly Ultimately Bounded Tracking for Uncertain Euler-Lagrange Systems with Unknown Time-Varying Input Delay

摘要

This paper proposes a robust compensator for a class of uncertain nonlinear systems subjected to unknown time-varying input delay. The proposed control law is based on the integral of past values of control and a novel filtered tracking error, which can compensate for large input delays. Sufficient gain conditions dependent on the known bound of the delay are derived using a Lyapunov based stability analysis, where suitable Lyapunov-Krasovskii (L-K) functionals are used to achieve a uniformly ultimately bounded (UUB) result. Simulation on an example of Euler-Lagrange (E-L) system is illustrated to evaluate the performance and robustness of controller for different values of time-varying input delay.