A Hierarchical Control Approach for Inter-station Operation of Virtually Coupled Train Set

Virtual coupling (VC) is an emerging technology to increase the flexibility and efficiency of railway services. To achieve the desired inter-station operation of a virtually coupled train set (VCTS), the movements of all train units in VCTS need to be optimized. However, in the speed-varying inter-station operation, VCTS is still difficult to be controlled accurately under disturbances, while satisfying safety constraints. To address this problem, we proposed a model predictive control (MPC) based hierarchical control approach, in which the lower layer uses MPC to achieve accurate reference tracking control based on the upper layer reference trajectory optimization for all train units. Finally, based on the data from a demonstration project of Beijing metros, experiments are conducted to demonstrate the performance of the proposed approach. Experimental results show that the proposed approach can reduce the average tracking error by 92.3% compared with a tuned PID control approach for VCTS. Moreover, the satisfaction of VCTS safety constraints can be guaranteed by the proposed MPC approach.