Modelling and analysis of a pantograph pneumatic actuator under large-catenary-gradient operation

Dynamic behaviour of railway pantographs are significantly impacted by catenaries with large gradients. In such scenarios, the pantograph response is largely governed by the base pneumatic actuator. Specifically for this actuator, it operates as a passively-regulated pneumatic suspension (PRPS) device, offering both constant-force actuation and passive suspension. Such device is crucial for the interaction dynamics, hence the contact quality, between the pantograph and overhead line system. The existing modelling approach of PRPS devices has evident limitations: (1) it focussed on predicting only a specific operation condition, (2) it relies on tuning non-physical parameters, rather than the underlying physics of each component, making the model unable to predict alternative designs. To address those limitations, in this work a physics-based nonlinear network model for a railway pantograph PRPS device is developed. Here, multiple operation conditions, including straight-wire and large-gradient cases, are considered. Validation of the model response under multiple operating conditions is achieved through testing. In addition, a model parametric study that varies component property is performed and experimentally verified. This suggests that the developed model can accurately predict multiple operating conditions, and be used to explore alternative designs for future performance enhancement.