When you think about highly-precise actuators, stepper motors probably aren’t the first device that comes to mind. However, as [Diffraction Limited]’s sub-micron capable micro-manipulator shows, they can reach extremely fine precision when paired with external feedback.

The micro-manipulator is made of a mobile platform supported by three pairs of parallel linkages, each linkage actuated by a crank mounted on a stepper motor. Rather than attaching to the structure with the more common flexures, these linkages swivel on ball joints. To minimize the effects of friction, the linkage bars are very long compared to the balls, and the wide range of allowed angles lets the manipulator’s stage move 23 mm in each direction.