Robust Control of Uncertain Euler-Lagrange Systems with Time-Varying Input Delay

Abstract

In this paper, a robust control law is proposed for the tracking control problem of a class of uncertain Euler-Lagrange (EL) systems subjected to randomly varying input delay. EL systems represent a large class of real-world systems such as robotic manipulator, unmanned mobile robots etc. In comparison to the existing predictor based approaches, the proposed Robust Time-Delay Controller (ROTDC) can negotiate input delay within a specified range having an arbitrary variation. Razumikhin-type stability analysis is employed to derive the controller gain to maintain system stability for a given range of delay. Further, the closed loop uncertain system is shown to be Uniformly Ultimately Bounded (UUB) employing the proposed ROTDC. As a validation of the concept, comparative experimental results with predictor based methodology are also provided using a nonholonomic wheeled mobile robot with different time varying input delays, which demonstrate the efficacy of the proposed controller.