Effect of the drive system on locomotive dynamic characteristics using different dynamics models

Based on the theory of vehicle-track coupled dynamics and gear system dynamics, a locomotive-track coupled spatial dynamics model is established by considering the dynamic effects of the gear transmission system. The vibration responses of a locomotive's major components are then simulated using three locomotive-track models, namely the proposed dynamics model with the gear transmissions, a locomotive-track coupled dynamics model that considers the traction motor, and the classical Zhai's model. The locomotive dynamic responses of the three models are extracted and compared to reveal discrepancies between them so as to explore the dynamic effects of the power transmission system and clarify potential applications of these models. The results indicate that the dynamic effects of the gear transmissions have a negligible influence on the lateral vibrations of the locomotive components. However, they have obvious effects on the vertical and longitudinal vibrations of the wheelset and the traction motor. Another advantage of the locomotive dynamics model that considers the dynamic effects of the gear transmissions is that the dynamic performance of the drive system can be assessed in the vehicle vibration environment. This study provides theoretical references that can assist researchers in choosing the most appropriate locomotive dynamics model according to their specific research purpose.