Adaptive fault-tolerant fixed-time cruise control for virtually coupled train set

In the cruise control of the virtual coupled train set (VCTS), the control algorithm with high stability, high accuracy, and fast convergence speed is the basic requirement for the smooth and efficient operation of the VCTS. To this end, this paper studies the problem of fixed-time cruise control for VCTS. To begin with, by analyzing the dynamic evolution of the VCTS in an actual environment, a second-order VCTS train-following dynamic model is formulated with considering actuator faults, uncertain resistance, unknown disturbances, and control input saturation. Then, an improved barrier functions-based fixed-time sliding model control method is proposed to deal with the state constraints (i.e., safe distance and speed limit). To deal with parametric uncertainty, adaptive fault-tolerant control and core function technologies are integrated into the same framework. Furthermore, by using a function approximation method to handle the control input saturation, an adaptive fault-tolerant fixed-time cruise controller is designed which not only guarantees the fixed-time stability of the VCTS but also copes with parametric uncertainty, state constraints, and input saturation. Finally, the effectiveness of the proposed method is validated in simulation analysis.