Robust Cooperative Control of Networked Train Platoons: A Negative-Imaginary Systems' Perspective

By virtue of the wide implementation of communication-based train control (CBTC) systems and moving-block signaling systems, cooperative control for trains shows great potential in improving line utilization, passenger comfort, and operation flexibility. However, the operation of train platoons faces great challenges induced by model uncertainties, unpredictable resistances, and time-varying disturbances. To address these problems, consensus-based robust cooperative control schemes are presented in this article for both homogeneous and heterogeneous train platoons. Taking the physical connection between carriages into consideration, each train in the platoon is modeled as a negative-imaginary (NI) system, and the NI property is rigorously proved in this article. In the foundation of cooperative control theories of NI systems, robust strictly NI controllers considering the network topology are utilized to track a predefined motion reference. The proposed controllers are robust to both mass uncertainties and external disturbances. Moreover, the line utilization for the railway system and the ride comfort for the passengers are improved using the proposed control schemes. Numerical simulations are given to showcase the effectiveness and robustness of the proposed controllers.