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There is an increasing demand in the field of construction equipment to simultaneously develop both a construction equipment system and a control strategy, especially when a short commissioning period is desired. Moreover, the manufacturer's engineering teams must satisfy the needs of operators in different geographical locations. Therefore, there is a need for a powerful software development tool, able to reproduce the behaviour of complex mechanical systems, such as large manipulators, mobile cranes and excavators, in transient conditions and with low calculation times, with the ultimate aim of realizing a "control-oriented" model able to perform real time simulations in a hardware in the loop (HiL) or software in the loop (SiL) environment. This approach can lead to great time savings, as it allows testing and debugging the control unit simultaneously with the development of the actual physical system to be controlled. In contrast, the development of a reliable multi-system model can be a valuable instrument in performing full system optimization, given the ability to simulate the interaction between various components (hydraulics, engine, and kinematics) under actual operating conditions. The ultimate aim of this research is to realize a customized control strategy, able to guarantee performance improvements (e.g. fuel consumption reduction) for the specific application. The complexity in modelling these systems is attributed to the inherently nonlinear hydraulic drive used to achieve precise motion and power control.The hydraulic systems are characterized by a superior power density in comparison with electrical or mechanical systems, but hydraulic systems are less efficient due to the energy conversions involved. In order to reduce the energy losses, new system layouts are proposed [1] to [3], but typically the systems are designed for satisfying the load requirements controlling the fluid flow generated by the pumps. Variable displacement pumps are essential for controlling the flow; in axial piston pumps, the displacement can be varied by tilting the swash plate, which can be achieved fast enough to meet the dynamic demands due to multiple loads. The swash plate angular position is controlled by means of an actuator working in feedback with the load; these types of pumps are known as load-sensing pumps. The load signals from the actuators are transferred to the pump regulators through the load-sensing line. A load-sensing, flow-sharing valve block was used for the application considered; flow sharing is a useful feature when the global flow rate required by the various elements exceeds the pump's maximum flow rate, especially in excavators where several simultaneous motions are required.A literature review shows that pump models could be conceived in a number of ways, either for analysing specific aspects in greater detail [4]

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