Discrete time fast sliding-mode control for permanent magnet linear motor with nonlinear extended state observer

In this paper, a nonlinear extended state observer (NLESO)-based discrete-time fast terminal sliding mode controller (FTSMC) is proposed for the high-precision position tracking of permanent magnet linear motor. The proposed control scheme consists a discrete-time FTSMC with a terminal type reaching law and a NLESO to cope with lumped uncertainties and external disturbance. Due to the fast terminal sliding manifold, the fast finite time zero convergence is well guaranteed. With properly chosen observer gains, the estimation accuracy of NLESO can be arbitrary increased, which significantly facilitates the engineering application practice. The boundedness of output tracking error has been proved and numerical simulations are conducted which verifies the effective of proposed control scheme.