Fluid control devices, systems, and methods are useful for articulating catheters and other elongate flexible structures. A modular manifold architecture includes plate-mounted valves to facilitate fluid communication along a plurality of fluid channels included in one or more multi-lumen shafts for articulating actuators comprising balloons within a balloon array, with the balloons often mounted on two or more extruded multi-lumen shafts. Valve/plate modules can be assembled in an array, and a proximal interface of the shaft(s) may have ports for accessing the balloon channels distributed along an axis of the interface. By aligning and engaging the proximal interface with a receptacle that traverses the plates of the manifold assembly, the ports can be quickly and easily sealed to associated channels of the various valve/plate modules using a quick-disconnect fitting.