An Adaptive Velocity-Sensorless Control Strategy of Multi-Locomotive Freight Trains Using a Non-Recursive Control and High-Gain Observer

Abstract

In recent years, the railway transportation sector has experienced significant growth, playing an important role in modern transportation systems. Large-scale freight trains often require multiple locomotives to provide sufficient traction during operation. A major challenge in freight train control is to ensure that the wagons follow the predefined reference velocity, especially under the influence of unknown external disturbances and varying freight loads across different trips. This paper proposes an adaptive control strategy without velocity sensors for freight trains with multiple electric locomotives. The control strategy is developed based on the non-recursive control framework with time-varying parameters. The elimination of velocity sensors is achieved through a high-gain observer (HGO), which enables accurate estimation of the velocity tracking error of the electric locomotives. The position and velocity tracking errors of the locomotives are proven to converge asymptotically to the origin using Lyapunov stability theory. Finally, simulation results are carried out to validate the effectiveness and reliability of the proposed control strategy.