Integration and Control of Electromechanical and Electrohydraulic Actuators in a Hybrid Primary Flight Control Architecture


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Art der Publikation:



Electro-mechanical Actuator (EMA); electro-hydraulic servo actuator (EHSA); primary flight controls; operating mode; more electric aircraft (MEA)


Olaf Cochoy, Udo B. Carl, F. Thielecke


Recent Advances in Aerospace Actuation System and Components

Moving towards the More Electric Aircraft, the introduction of electromechanical actuators (EMA) into primary flight controls is an essential element. However, several challenges such as possible jamming, proper damping characteristics, and actuator passivation are related to these actuators. Besides these issues, reliability, mechanical wear, and electrical integration are uncertainties, which today render a purely EMA driven primary flight control surface unlikely. A hybrid actuator configuration with conventional electro-hydraulic servo actuators (EHSA) and EMA is thus a consequent first step to introduce EMA into primary flight controls. In this article, three different EMA designs-ball screw/gear stage, direct drive, hingeline- are presented and general advantages and disadvantages with respect to the above mentioned issues are discussed. A multiinput- multi-output control concept is then presented, enabling the operation of a hybrid configuration in both active/active operating mode as well as in a new operating mode, in which the EMA is actively controlled such that it does not carry external air loads (active/noload), with minimum force fighting. Finally, an experimental test rig comprising an airworthy EHSA and a hingeline EMA is outlined.