Hi, i'm doing some research into fly-by-wire system on aircraft and need some more information on actuators. I know that electrical signals are sent to the actuator from an onboard computer, but I'm not sure how the actuators then move the control surfaces. Do they use hydraulics? If so how do they convert the electrical signal into movement in the hydraulic system. From my knowledge of hydraulics I know that some form of force needs to be applied to move the piston. Is an electric motor used for this? Thanks, any help will be appreciated.