This paper presents a model of an electrohydraulic fatigue testing system that emphasizes components upstream of the servovalve and actuator. Experiments showed that there are significant supply and return pressure fluctuations at the respective ports of the servovalve. The model presented allows prediction of these fluctuations in the time domain in a modular manner. An assessment of design ch...

In industrial applications, the dynamic characteristics of the servo-hydraulic system are always complex and highly nonlinear. Moreover, there are too many uncertainties in it; for example, the viscosity of oil, the bulk modulus, the oil volume, the system pressure, the wear and the cavitations. The loading conditions are usually rather unsteady, and the loading forces change in a wide range du...