A NEW SERVOVALVE SIMPLIFIED FLUID DYNAMIC MODEL SENSITIVE TO SYSTEM HYDRAULIC CAPACITIES

Designing modern flight control systems requires highly detailed models to analyse individual components or subsystems. However, for tasks like preliminary design, monitoring, diagnostics, or prognostics, simpler yet sufficiently accurate models are necessary. Literature offers various simplified numerical solutions that can simulate the fluid dynamic behaviours of specific valve geometries with varying levels of detail and accuracy. These simplified models usually calculate the differential pressure regulated by the valve based on its spool opening and the flow rate it manages. In certain applications, such as asymmetric hydraulic jacks, regenerative actuators, or systems where fluid compressibility is significant, models focused solely on differential pressure are insufficient. Instead, new simplified fluid dynamic models are needed to determine the flow rate delivered by the valve as a function of spool displacement and differential pressure. This paper introduces a new synthetic fluid-dynamic valve model-a lumped parameters model with a semi-empirical formulation-that considers spool position, hydraulic capacity, variable supply pressure, and leakage between the output ports connecting the valve to the motor element.