Study of new fluid dynamic nonlinear servovalve numerical models for aerospace applications

The development of modern flight control system requires more and more highly detailed computer models in order to analyze their specific behavior as a whole or related to their components and subsystems; on the other hand, especially in the phases of preliminary design or development of diagnostic or prognostic algorithms, it is necessary to implement simplified models that are able to combine sufficient levels of accuracy and reliability with reduced calculation times and computational costs. In this paper, the authors analyze the possibility of building more simple, synthetic models, with the aim to maintain an acceptable level of accuracy but being able to analyze the dynamic behavior of entire systems. This work focuses on the numerical models related to fluid-dynamics of servovalves, where the related algorithms are characterized by a semi-empirical formulation and will take into account the effects of variable supply pressure and leakage (which is related to the control ports connecting the valve to the motor elements). Two new models are proposed and compared with a detailed reference. This comparison is performed by evaluating the performance of the different models and their ability to describe the fluid dynamic behavior of the considered valve.