Novel fluid dynamic nonlinear numerical models of servovalves for aerospace

Modern flight control system often requires the development of more and more highly detailed numerical simulation models in order to analyze their specific behavior as a whole or related to their components and subsystems. Especially during preliminary design activities or in the development of diagnostic or prognostic algorithms, it is often required to implement simplified numerical models able to simulate the actual behavior of the considered system, combining appropriate levels of accuracy and reliability with low calculation times and moderate computational efforts. In this work, authors investigated the feasibility of new simplified numerical models, aiming to provide faster models able to analyze the dynamic behavior of entire systems and, at the same time, able to guarantee a suitable level of accuracy. In particular, this paper concerns novel fluid-dynamics numerical models simulating the performance of servovalves. These algorithms are based upon a semi-empirical formulation and, although simplified, they are able to take calculate the effects of variable supply pressure and leakages (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.