Adaptive Fuzzy Event-Triggered Sliding-Mode Control for Uncertain Euler-Lagrange Systems With Performance Specifications

This article addresses the design of an event-triggered finite-time singularity-free terminal sliding-mode control algorithm for the tracking of Euler-Lagrange (EL) systems subject to state/error constraints, unstructured dynamics, and external disturbances. First, a novel sliding-mode manifold (SMM), not only devoted to the finite-time convergence of tracking errors to a small residual set around zero but also ensuring stringent constraint requirements, is proposed. The SMM is available for both the constrained and unconstrained EL systems in a unified manner with no structural changes. Then, a fuzzy logic system is introduced to dynamically compensate for uncertainties in the system. An extra robustifying term is added to the training policy to accelerate online learning. Also, an event-triggeredmechanism is integrated into the tracker design procedure to reduce the frequency of signal transmission. Stability analysis proves that all the closed-loop signals are uniformly bounded, and numerical simulations further illustrate the theoretical findings.