Simulative Comparison Approach of Electro-Hydrostatic Actuator Circuits in Excavators

Abstract Over the past years, a variety of electrified construction machinery became commercially available. The electrification of mobile machinery can be considered the most important system change in mobile hydraulics of the last decades. The challenge now, is to optimize such systems to be more efficient, affordable, and environmentally friendly in the future. A highly promising approach is the use of electro-hydrostatic actuators (EHA) which are known for high energy-efficiency. Still a widespread use in heavy mobile machinery currently cannot be observed which might be a consequence of unwanted system behavior under certain working conditions. Since there are many different electro-hydrostatic actuator topologies known in literature, it is difficult to determine the most suitable one for implementation in excavators. This paper introduces an approach to compare different circuits through simulations in a structured way. By using an abstracted dig and dump cycle and subdividing it into smaller part operations a direct comparison becomes possible. The abstraction of the dig and dump cycle reduces the modeling effort, variables needed to be considered and simplifies the analysis of system behavior. Four circuits are compared exemplarily to each other for regenerative operation from standstill. Only circuits with a single prime mover and load holding valves are investigated regarding cost-effectiveness and compactness of the EHA. The circuits are modeled in a lumped parameter hydraulic simulation and parameterized for use on a 1.8-ton excavator.