Prescribed performance control of Euler–Lagrange systems with input saturation and output constraints

Abstract

SummaryIn this article, we investigate the performance‐guaranteed tracking control for Euler–Lagrange (EL) systems subject to input saturation and output constraints. The prescribed performance and output constraints are first considered for EL systems with input saturation. Time‐varying barrier Lyapunov function (BLF) is employed to ensure constraint satisfaction. An adaptive control method for EL systems with saturation is put forward by adding a speed transformation into the BLF and designing auxiliary variables to the system. Subsequently, neural network is introduced to compensate for uncertainties of systems. In combination with backstepping technique, it is demonstrated that the controller not only guarantees that the tracking error converges to a preset compact set near zero at a specified decay rate, but also ensures that the output always stays within a given boundary. Simulation results further demonstrate the effectiveness of the proposed control scheme.