Development of a Miniature Air-bearing Stage with a Moving-magnet Linear Motor

We propose a new miniature air-bearing stage with a moving-magnet slotless linear motor. This stage was developed to achieve the precise positioning required for submicron-level machining and miniaturization by introducing air bearings and a linear motor sufficient for mesoscale precision machine tools. The linear motor contained two permanent magnets and was designed to generate a preload force for the vertical air bearings and a thrust force for the stage movement. The characteristics of the air bearings, which used porous pads, were analyzed with numerical methods, and a magnetic circuit model was derived for the linear motor to calculate the required preload and thrust forces. A prototype of a single-axis miniature stage with dimensions of 120 (W) × 120 (l) × 50 (H) ㎜ was designed and fabricated, and its performance was examined, including its vertical stiffness, load capacity, thrust force, and positioning resolution.