An actuator system includes a motor and an actuator positioning member to be driven by the motor from a start position to an actuated position. The system also includes a harmonic drive assembly between the motor and the actuator positioning member arranged to transfer torque from the motor to the actuator positioning member at a gear ratio of greater than 1:1. The system further includes means for disconnecting the harmonic drive assembly in response to failure of the motor and/or torque transfer such as to allow the positioning member to return to the start position.