Simulation and Analysis of Non-Hybrid Displacement-Controlled Hydraulic Propulsion Systems Suitable for Railway Applications

Abstract

A hydraulic propulsion system is a convenient choice for many earth-moving and construction machineries because of their large mass and low speed required during normal operations. Due to the increasing fuel cost occurred during the last decade, a growing attention in displacement-controlled architectures is taking place. The key factors that motivate this interest are the energy-saving actuation and the easy implementation of the regenerative braking. In this regard, solutions like hydrostatic transmissions and secondary controlled hydraulic motors were already investigated for generic applications. Nevertheless, in some machines it is necessary to have more axles driven while guaranteeing a precise control of the tractive/braking torque: this is the case of the railway machineries. Thus, this research paper is aimed at comparing the non-hybrid displacement-controlled architectures mentioned above applied to a railway track maintenance machine. Discussing the control algorithms and analyzing some virtual simulations performed with high-fidelity dynamic models are part of the work. Specifically, after confirming the proper system functioning, the final targets are gaining deeper insight into the system behaviors and determining the most convenient layout in terms of energy consumption.