Multiairgap friction direct drive linear actuator with permanent magnets

These article deals with a special high performances, large extension, direct drive linear actuator for an aeronautical application. The purpose of this actuator is to remove the mechanical transmission, classically used, in order to increase the reliability. This actuator can reach very high performances in terms of mass and volume because of the multiplication of the number of airgaps. A particularity of this actuator is also the friction of the movable parts on the fixed parts. It allows to use very small dimensions on the active parts and so to increase the performances. The experimental results confirm the high performances of this structure (~ 1000 N/kg and ~ 5000 N/dm³).