Gray box modeling of an excavator’s variable displacement hydraulic pump for fast simulation of excavation cycles

This paper describes the results of a study focused on the application of gray box modeling methodology on an excavator's hydraulic pump. This modeling approach has been adapted to accelerate the control system development time for a complete excavator, while providing accurate system dynamics. This mathematical model has been developed using the bond graph methodology. The excavator is described by two models: a hydraulic model and a kinematic model; dynamic parameters are continuously calculated during an excavation cycle, providing a platform to study the pump's behavior. The gray box model of the variable displacement pump has been validated on the basis of a set of experimental data collected on a test rig and on the field using an excavator. Herewith the results of this study are presented.

► This paper presents the modeling methodology adapted to develop the hydraulic components and circuit of a complete excavator.
► A combination of known modeling techniques, black box, white box and gray box models, have been developed and these principles have been integrated in the frame work of the bond graph modeling methodology.
► The advantage of the approach described in this paper is that it provides accurate predictions of the pumps dynamic behavior in a complete model of an excavator while not demanding long computational times.
► An array of experiments both in a laboratory and field environment have been carried out to validate the model’s capabilities.