Nonsingular fast terminal sliding-mode stabilizer for a class of uncertain nonlinear systems based ondisturbance 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 satis es the nite-time convergence of the disturbance approximation error and the suggested nite-time stabilizer assures the presence of the switching behavior around the switching curve in the nite 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 e ectiveness of the o ered procedure are con rmed by numerical simulation results.