Mathematical modeling of EHA system for flight control surface actuation

Electro-Hydrostatic Actuator (EHA) systems have been increasingly favored for flight control surface actuation for its precision control, increased reliability and its merit to eliminate completely the centralized hydraulic system by a self-contained actuator. This work briefly outlays, the architecture of EHA systems and presents a detailed mathematical modeling for the EHA system with Variable Motor Fixed Pump (VMFP) configuration to carry out system level simulations. In particular, an integrated plant model considering the flight control surface' inertia and aerodynamic loads on it has been presented. The work proposes a first of its kind model of the EHA-VMFP system built on Simulink platform. The plant models are SISO systems and give no details about system performance evaluators. The Simulink model on the contrary will negate this drawback and provide a coherent approach into the investigation studies of system performance evaluators. The results from the simulations have been verified through analytical calculations. The paper implicitly instigates studies into much more complex tasks of modeling axial piston pumps, servo motors etc., and in such studies the usefulness of Simulink modeling has been showcased.