Adaptive and robust automatic train control systems with input saturation

Various advanced control techniques have been applied in automatic train control (ATC) systems. In most cases, input constraint exists commonly in ATC systems due to actuator saturation, which greatly influences their performance and stability. This paper addresses the issue of control input saturation in adaptive control of ATC systems. An emendatory tracking error is evaluated and an adaptive robust control scheme is applied simultaneously for preventing the closedloop system and adaptation law in the presence of input saturation from breakdown and destruction. The stability of the closed-loop system under the proposed control law is guaranteed via Lyapunov stability theory. Simulation results are presented to demonstrate the effectiveness of the proposed control scheme. The system is finally validated to be robust against unknown nonlinear dynamics caused by complex environments.