Patent ID: 7456527

Claim:
A system for carrying and moving an object in a plane, comprising: an object carrier; a first and a second linear actuator configured to support said object carrier and move said object carrier in a first direction, said first and second linear actuators extending in parallel along said first direction, said first and second linear actuators being electromagnetic linear actuators comprising: a magnetic structure, and a coil structure, wherein the coil structure and the magnetic structure are positioned relative to each other and separated by an air bearing attached to the coil structure or the magnetic structure and configured to support said object carrier during motion at a first position along said first direction, the first position being on one end of whichever of the magnetic structure or coil structure is connected to the object carrier, and at a second position displaced from the first position along said first direction, the second position being on the opposite end of whichever of the magnetic structure or coil structure is connected to the object carrier, wherein the first and second positions and whichever of the magnetic structure or coil structure is connected to the object carrier are substantially in a same plane; and a third and a fourth linear actuator configured to move said object carrier in a second direction, said third and fourth linear actuators extending in parallel along said second direction, wherein both the coil structure and the magnetic structure of the first and second linear actuators are moveable with respect to each other or both a coil structure and a magnetic structure of the third and fourth linear actuators are moveable with respect to each other, the coil structure or the magnetic structure of the respective pair of coil structure and magnetic structure of the respective linear actuator configured as a balance mass to receive reaction forces arising from the movement of the other of the coil structure or the magnetic structure.