A torque balance servo is provided for use in conjunction with a fluidly-controlled device. The torque balance servo includes a pivoting table assembly and an electromagnetic force bias mechanism. The pivoting table assembly includes: (i) a pivoting table configured to pivot about a rotational axis, and (ii) a roller assembly mechanically coupled to the fluidly-controlled device and contacting a surface of the pivoting table. The electromagnetic force bias mechanism is disposed proximate the pivoting table assembly and configured to exert a variable torsional force about the rotational axis of the pivoting table.