In this paper we discuss the modeling and control of a pneumatic two-degree-of-freedom fine positioner for, but not restricted to, robotic applications requiring small, fast and precise movements. The micro-manipulator actuation is based on a new technique : motion is generated by the deformation of metal bellows controlled by air pressure. This technique yields a direct-drive pneumatic actuator capable of producing high force with negligible static friction and no backlash over a relatively large operating range. The trade-off however is that a well-adapted control strategy is necessary to achieve fast and accurate motion. The development of a linearized model of reasonable complexity and the selection of a position state feedback control law based on this model are the main topics of our contribution, which also comprises a description of the fine positioner. In order to meet the requirements of micro-manipulation applications, the tuning of the control scheme parameters are analyzed. The development of the actuator control strategy is completed by its implementation that involves, for the sake of simplicity and low-cost, only position sensing. All this results in a proper control scheme for metal bellows actuation in the context of robotics applications; its performance is evaluated both by simulation and from the experiences conducted on the actual prototype. The fine positioner has an isotropic dynamic behavior with a settling time inferior to 28 ms, it is capable of developing up to 250 N of peak force and features a positioning accuracy of 2 mu m over an operating range of 2 mm. Finally, the application of the fine positioner to robotic assembly systems is also presented and analyzed.