According to one embodiment, a trim actuator for a pilot input device includes a driven member and a driving member configured to receive mechanical energy from a power source. A magnetorheological (MR) fluid is disposed between the driving member and the driven member and configured to transmit a variable amount of mechanical energy from the driving member to the driven member such that the driven member moves in a first direction. An output member configured to be coupled between the driven member and the pilot input device. A spring is in mechanical communication with the output member and configured to apply a force in a second direction opposite of the first direction. A magnetic circuit is configured to control movement of the pilot input device by varying the strength of a magnetic field delivered towards the first MR fluid.