Modeling and Verification of an Excavator System – Axial Piston Pump, Kinematics and Prime Mover Models

This paper describes the results of a study focused on the mathematical modeling of an excavator hydraulic system that is a very complex nonlinear plant. To design and tune such a complex control system an extremely good nonlinear model of the plant is necessary. A nonlinear mathematical model of an excavator has been developed using the AMESim® modeling environment to replicate actual operating conditions. The excavator model is described by mathematical models of the main pump, a completely developed kinematic model and a model of the prime mover. The model of the prime mover is based on a mean value engine model and is capable of replicating the dynamic behavior of the engine, thereby providing the actual engine speed as a function of the torque required by the system. The objective of this research is to develop a complete simulation model of an excavator with the capability of reproducing the actual characteristics of the system, this has been achieved through a balance of semi empirical models, while maintaining the flexibility of varying the gain characteristics of the components for enhancing system performance. The benefit of this model is that it provides an advantage on computational time for complex system modeling while not compromising on the systems characteristics. This paper presents a validated model of an excavator system comprising of pump, kinematics and the prime mover with preliminary verification of individual components and results of a complete excavator system.