Nonsingular fast terminal sliding-mode stabilizer for a class of uncertain nonlinear systems based on disturbance observer

This paper investigates a novel nonsingular fast terminal sliding-mode control method for the stabilization of the uncertain time-varying and nonlinear third order systems. The designed disturbance observer satisfies the finite-time convergence of the disturbance approximation error and the suggested finite-time stabilizer assures the presence of the switching behavior around the switching curve in the finite time. Furthermore, this approach can overcome the singularity problem of the fast terminal sliding-mode control technique. Moreover, knowledge about the upper bounds of the disturbances is not required and the chattering problem is eliminated. Usefulness and effectiveness of the offered procedure are confirmed by numerical simulation results. (C) 2017 Sharif University of Technology. All rights reserved.