Low friction, high precision actuator

A low-friction, high precision device for transforming rotational motion into rectilinear motion comprising:

• a male element;
• a female element, wherein said female element is adapted to fit over said male element such that said female element is separated from said male element by a first gap, said female element including gas inlet means for allowing compressed gas to enter said first gap, thereby allowing the formation of a first gas support cushion between said male and female elements, whereby said first cushion is capable of maintaining the separation of said male and female elements;
• and
• a guide element for allowing said female element to translate parallel to said male element and for preventing said female element from rotating, wherein said guide element and said female element are separated by a second gap, said guide element including gas inlet means for allowing the compressed gas to enter said second gap, thereby allowing the formation of a second gas support cushion between said female element and said guide element, whereby rotation of said female element is capable of being resisted by said second cushion;
• wherein said female element is capable of being suspended by said first and second cushions;
• wherein said male and female elements are magnetically coupled;
• and
• wherein rotation of said male element is capable of causing said female element to translate parallel to said male element by magnetic traction;
• whereby translation of said female element is substantially frictionless;
• whereby said female element is vibrationally isolated.

A drive system comprising:

• a compressed air source;
• a drive motor having a rotor and a stator;
• a leadscrew attached to said rotor, said leadscrew having an outer surface including a magnetizable portion with a helical flange defining a first helical groove, said magnetizable portion having an outer diameter;
• and
• a nut having:
• an outer surface;
• an inner radial surface, including a magnetizable portion with a helical flange defining a second helical groove, wherein said first helical groove matches said second helical groove, and wherein said magnetizable portion has an inner diameter greater than said outer diameter of said magnetizable portion of said leadscrew, thereby forming a gap between said nut and said leadscrew;
• and
• a magnetic source disposed between said inner radial surface and said outer surface;
• wherein said nut is provided with at least one air passage between said outer surface and said inner radial surface;
• wherein said compressed air source is connected to said air passage to provide air to said gap, thereby creating an air cushion between said nut and said leadscrew, whereby said nut is substantially prevented from contacting said leadscrew;
• wherein said magnetic source induces a closed magnetic circuit through said magnetizable portion of said nut and said magnetizable portion of said leadscrew;
• and
• wherein rotation of said leadscrew causes said helical flange of said magnetizable portion of said leadscrew to magnetically attract said helical flange of said magnetizable portion of said nut, thereby causing said nut to translate rectilinearly along said leadscrew.

A method for precisely transforming rotational motion of a first element into rectilinear motion of a second element comprising:

• aerostatically suspending the second element while simultaneously preventing the second element from rotating;
• aerostatically suspending the first element magnetically coupling the first and second elements;
• and
• rotating the first element.