Variable displacement electro-hydrostatic actuator

The author discusses the effects of pump displacement on electro-hydrostatic actuator (EHA) performance characteristics and the possible advantages of using a variable displacement pump in an EHA. Issues discussed are heating, size, and stiffness. It is noted that the EHA offers the possibility of varying the coupling ratio by varying the pump displacement. The variable coupling ratio could be used to increase actuator stiffness, to decrease package size, and to decrease package heating. An EHA employing a variable displacement pump has been designed and built, and the actuator will be tested once assembly of the package is completed