Robust prescribed performance control for Euler–Lagrange systems with practically finite-time stability

A robust prescribed performance control (PPC) scheme with practically finite-time stability is proposed for Euler–Lagrange systems with completely unknown dynamics. Firstly, a novel prescribed performance function (PPF) is devised to guarantee the system state to reach its stability region within predefined time. Then, employing the nonsingular terminal sliding mode technique generates an auxiliary manifold, based on which a practically finite-time stable controller is developed without a priori knowledge of the unknown dynamics. Compared with the existing works, the primary contribution is that: not only the prescribed performance is achieved under the proposed PPC scheme, but all state variables are guaranteed to be practically finite-time stable. Finally, three groups of simulations are organized to validate the effectiveness of the proposed scheme.