Moving coil type planar motor control
First Claim
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1. A planar motor comprising:
- a magnet array having a plurality of magnets;
a coil array having a plurality of coils;
a control system configured to selectively provide electric current to the coil array for translational movement in two degrees of freedom and rotation in a third degree of freedom, said current being controlled to at least substantially reduce force and torque ripple in said movement.
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Abstract
A control system for a moving coil type planar motor is disclosed that operates with a commutation circuit requiring a decreased number of amplifiers as compared to moving magnet type planar motors. The control system permits positioning with three degrees of freedom. Motor force and torque ripple during translational forces and yaw torque is minimized by the control system.
22 Citations
26 Claims
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1. A planar motor comprising:
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a magnet array having a plurality of magnets;
a coil array having a plurality of coils;
a control system configured to selectively provide electric current to the coil array for translational movement in two degrees of freedom and rotation in a third degree of freedom, said current being controlled to at least substantially reduce force and torque ripple in said movement. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A lithographic instrument comprising:
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a positioning stage;
a planar magnet array;
a planar coil array coupled to the positioning stage;
a control system configured to selectively provide electric current to the coil array for translational movement in two degrees of freedom and rotation in a third degree of freedom, said current being controlled to at least substantially reduce force and torque ripple in said movement.
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16. A method for controlling a planar motor for positioning in three degrees of freedom, the method comprising:
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positioning a movable coil array over a fixed magnet array, the coil array having coils generally disposed in a plane defining first and second directions that are substantially orthogonal to one another, and the magnet array having magnets with magnetic fields;
determining currents to be applied to coils to generate substantially ripple free translational forces between the coil array and the magnet array in the first and second directions and substantially ripple free torque about a third direction perpendicular to the plane;
applying currents as determined to the coils to move the coils. - View Dependent Claims (17, 18, 19)
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20. A system for controlling a planar motor, said motor including an array of coils for producing translational forces in two degrees of freedom, said system comprising:
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a controller;
a sensor for sensing position of the coils;
a first comparator for receiving position feedback from the sensor; and
a second comparator for receiving input from a position disturbance in a third degree of freedom, wherein said controller at least substantially applies a compensation function to said position disturbance and provides a corrected output position. - View Dependent Claims (21)
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22. A planar motor comprising:
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magnet array means;
coil array means; and
control means providing electric current to said coil array means for controlled movement in three degrees of freedom including means for at least substantially eliminating ripple.
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23. A stage system comprising:
a planar motor, said planar motor comprising a magnet array having a plurality of magnets, a coil array having a plurality of coils, and a control system configured to selectively provide electric current to the coil array for translational movement in two degrees of freedom and rotation in a third degree of freedom, said current being controlled to at least substantially reduce force and torque ripple in said movement.
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24. An exposure apparatus comprising:
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an illumination system that supplies radiant energy; and
a stage system comprising a planar motor, said planar motor comprising a magnet array having a plurality of magnets, a coil array having a plurality of coils, and a control system configured to selectively provide electric current to the coil array for translational movement in two degrees of freedom and rotation in a third degree of freedom, said current being controlled to at least substantially reduce force and torque ripple in said movement, wherein said stage system carries at least one object disposed on a path of said radiant energy. - View Dependent Claims (25)
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26. A wafer comprising an image, wherein said image is formed with an exposure apparatus comprising:
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an illumination system that supplies radiant energy; and
a stage system comprising a planar motor, said planar motor comprising a magnet array having a plurality of magnets, a coil array having a plurality of coils, and a control system configured to selectively provide electric current to the coil array for translational movement in two degrees of freedom and rotation in a third degree of freedom, said current being controlled to at least substantially reduce force and torque ripple in said movement, wherein said stage system carries at least one object disposed on a path of said radiant energy.
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Specification