Hydro-Mechanical analysis and modeling of a bent-axis unit

Abstract Although the academic literature contains many contributions presenting different modeling approaches of positive displacement machines, some architectures, such as bent-axis units, have been studied less than other types, such as gear or swash plate units, in recent years. This article presents the hydro-mechanical modeling of a reference bent-axis unit that can function as a pump or a motor. The study adopts a lumped parameter approach to examine the hydro-mechanical aspects of the machine in detail, emphasizing the main components and their interconnections. For each main component, the study begins with the kinematic aspects and ultimately solves the dynamic analysis with equilibrium equations of forces and moments. Additionally, the model incorporates parametric, vector, and modular features to generalize the analysis to similar geometries and avoid limiting its usage to a single operating mode. A genetic algorithm was employed to address the critical challenge of parameterizing lumped-parameter models for hydraulic machines, particularly with regard to the geometric and frictional characteristics of lubricating gaps. This algorithm uses experimental measurements of mechanical and volumetric efficiency within a defined operating range. This methodology robustly identifies model parameters, which can support machine design and operational behavior analysis within complex hydraulic systems.