An object support positioning device configured to position an object support includes first and second side-beams having respective first and second sliders mounted thereon, first and second motors configured to move the first and second sliders along each respective side beam, a cross beam mounted proximate first and second ends thereof to the first and second sliders respectively and having a third slider mounted thereto, the cross-beam and the first and second slider being mounted together, and a third motor configured to move the third slider longitudinally along the cross-beam, the third slider being adapted to support the one object support. A fluid bearing is provided in at least one of the first, second and third sliders, the fluid bearing including multiple bearing surfaces to exert reaction forces in a first direction, the first direction being perpendicular to the sliding direction of the at least one slider.