Tracking Control for High-Speed Train With Coupler Constraints

Coupler systems are critical to the secure operation of the high-speed train. For this reason, this paper investigates the tracking control problem for the train under coupler displacement constraints. Firstly, by considering the security constraints and multiple disturbances, a multiple point-mass model of the train containing coupler displacements is established. Then, a disturbance observer is introduced to eliminate the adverse effects of complex disturbances on train operation, thereby improving the train's anti-disturbance capability. With the help of Lyapunov stability analysis, a new upper bound of observer estimation error is developed. Next, an input compensation signal is designed to address the issues of the coupler constraints and the low control accuracy based on disturbance observer. The state deviations of the train system caused by the disturbances can be almost completely compensated by the input compensation controller. Finally, a sufficient condition is provided to ensure that the coupler constraints are not violated throughout the entire train operation. Even if the couplers are stretched or compressed under the initial condition, the compensation signal could still ensure that the couplers work safely. Simulation experiments confirm that the designed compound controller can ensure the coupler always satisfies the constraint condition and effectively suppresses external disturbances, achieving safe and high-precision tracking control of the train.