Adaptive Nonsingular Terminal Sliding Mode Tracking Control for High-speed Trains With Input Constraints and Parametric Uncertainties

In this paper, a finite-time tracking control strategy for high-speed trains (HSTs) subjected to input constraints and parameter uncertainties is proposed based on adaptive nonsingular terminal sliding mode control (ANTSMC), which achieves the fast and precise displacement-speed trajectory tracking and energy saving results. The dynamic model of HST is established with the basic, additional, and external disturbances firstly. To handle input constraints, a smooth hyperbolic function is designed to approximate saturation function, which guarantees that the control signal does not exceed traction/braking characteristics and ensures safe operation. Then, an adaptive mechanism is used to estimate the upper bounder of the lumped uncertainty and controller’s parameters. Subsequently, the proposed ANTSMC methodology not only assures the finite-time convergence of position and velocity tracking errors, but also effectively compensates parameter uncertainties of the proposed model. Finally, numerical simulations indicate that the proposed method spends the less traction energy in obtaining the better tracking performance of HST.