Nonlinear estimator-based funnel tracking control for a class of perturbed Euler-Lagrange systems

In this article, a nonlinear estimator-based funnel perturbation rejection control method is investigated to manage the trajectory tracking problem of a class of perturbed Euler-Lagrange (EL) systems. To reinforce the perturbation rejection ability, perturbation estimators with nonlinear dynamics are established by employing a filtering operation, which can result in asymptotic convergence of estimation errors. Besides, by devising funnel variables with an exponential decaying function, a funnel control strategy is constructed to ensure tracking errors restricting into a prescribed region under the influence of persistent perturbations. Moreover, the tracking errors of the Euler-Lagrange system are concluded to be asymptotic stability with prescribed performance via Lyapunov stability theory. Finally, simulations validate the effectiveness of the developed control technology.