Abstract: Electrohydraulic systems play a pivotal role in controlling gas turbine engines. One of the most challenging problems in electrohydraulic control systems is modeling the non-linearity of fluid behavior due to special shaped orifices. Previous published studies have not treated modeling of such hydraulic systems in much detail, although they are widely used in aircraft engines and ground vehicles equipped with gas turbine engines. Presenting a validated model for an electrohydraulic position control system is fundamental to design and compare the effect of different control techniques on the system behavior.
In this paper, a detailed study of a fuel based electrohydraulic position control system was presented. This system is used in an air gas turbine engine of a ground equipment. The system controls the engine's air inlet guide vanes (IGV) position by means of linear hydraulic actuator. This actuator, in turn, is controlled via contactless electrohydraulic servo solenoid valve. A test rig was built to expedite measuring the actual system response and controlling it. A mathematical dynamic model was derived and solved using SIMULINK, a Matlab® application. Predicted results were compared with the experimental measured results. The comparison showed that the most extreme difference between the measured and predicted results was less than 5%. Therefore, the presented model could be used to design and compare the effect of different control techniques on the system behavior for further development.