Abstract: A plurality of fluid-operated rams, e.g., for positioning the rolls of a sheet-metal bending machine, are each actuated by a respective servovalve and are each connected to a respective potentiometer whose output resistance varies in accordance with the position of the ram. The rams are grouped in pairs and one potentiometer of each pair is energized with positive voltage, the other with negative voltage so that a combined signal can be produced indicating the relative positions of the two rams of the pair. The combined signal representing the position deviation is fed to two separate amplifiers where it is combined with voltages of opposite polarity and then fed to the servovalves of the pair of rams. Thus the one servovalve is closed partially if its ram advances on the other ram. Similarly a plurality of such rams can be interconnected with all but at most two rams from two different pairs so that all ram positions will be equalized.