An inlet guide vane assembly for a centrifugal compressor includes a plurality of guide vanes, a drive structure coupled to the plurality of guide vanes, an actuator; and an actuation mechanism. Rotation of the drive structure is transitions the plurality of guide vanes from a first position to a second position. The actuation mechanism causes the drive structure to transition the plurality of guide vanes between the first and second positions based on operation of the actuator. The actuation mechanism imparts a first amount of rotational force to drive the drive structure when the guide vanes are in the first position, and a second amount of rotational force when the guide vanes are in the second position. The actuation mechanism provides a mechanical advantage to the actuator when the guide vanes are in the first positions as compared to when the guide vanes are in the second position.