Abstract: A method for moving a stage relative to a base includes coupling a magnet assembly to the stage; coupling an array of coils to the base; and directing current to at least one of the coils with a control system that includes a processor to generate a force that levitates the stage relative to the base and moves the stage relative to the base. In one embodiment, the control system generates at least one current command that levitates and moves the stage while inhibiting the excitation of a first targeted flexible mode.

Abstract: A stage assembly (10) includes a stage (14), and a fluid actuator assembly (24) that moves the stage (14). The fluid actuator assembly (24) includes a piston housing (32) that defines a piston chamber (34); (ii) a piston (36) that separates the piston chamber (34) into a first chamber (34A) and a second chamber (34B); (iii) a supply valve (38C) that controls the flow of the working fluid (40) into the first chamber (34A); and (iv) an exhaust valve (38D) that controls the flow of the working fluid (40) out of the first chamber (34A). The supply valve (38C) has a supply orifice (250G) having a supply orifice area, and the exhaust valve (38D) has an exhaust orifice (352G) having an exhaust orifice area. Moreover, the supply orifice area is different from the exhaust orifice area. Further multiple valves of different sizes can be used in combination for the supply and exhaust for each chamber (34A), (34B).

Abstract: A stage assembly (10) includes a stage (14), and a fluid actuator assembly (24) that moves the stage (14). The fluid actuator assembly (24) includes a piston housing (32) that defines a piston chamber (34); (ii) a piston (36) that separates the piston chamber (34) into a first chamber (34A) and a second chamber (34B); (iii) a supply valve (38C) that controls the flow of the working fluid (40) into the first chamber (34A); and (iv) an exhaust valve (38D) that controls the flow of the working fluid (40) out of the first chamber (34A). The supply valve (38C) has a supply orifice (250G) having a supply orifice area, and the exhaust valve (38D) has an exhaust orifice (352G) having an exhaust orifice area. Moreover, the supply orifice area is different from the exhaust orifice area. Further multiple valves of different sizes can be used in combination for the supply and exhaust for each chamber (34A), (34B).

Abstract: A stage mover for moving a stage relative to a stage base includes a conductor assembly and a magnet assembly. The conductor assembly is coupled to the stage base and a plurality of coil units with each coil unit having one or more coils. Each of the coils has a coil width. The magnet assembly interacts with the conductor assembly and includes a plurality of spaced apart magnet arrays. Each of the magnet arrays is spaced apart from each adjacent magnet array by an array gap that is at least equal to the coil width so that independent and symmetric magnetic flux distribution can be achieved for each of the magnet arrays.

Abstract: A method for moving a stage relative to a base includes coupling a magnet assembly to the stage; coupling an array of coils to the base; and directing current to at least one of the coils with a control system that includes a processor to generate a force that levitates the stage relative to the base and moves the stage relative to the base. In one embodiment, the control system generates at least one current command that levitates and moves the stage while inhibiting the excitation of a first targeted flexible mode.

Abstract: A stage assembly for positioning a device includes: (i) a stage that retains the device; (ii) a base; (iii) a mover assembly that moves the stage along a first axis, along a second axis, and along a third axis relative to the base; (iv) a magnetic sensor system that monitors the movement of the stage along the first, second and third axes, the magnetic sensor system generating a magnetic sensor signal; (v) a second sensor system that monitors the movement of the stage along the first, second and third axes, the second sensor system generating a second sensor signal; and (vi) a control system that controls the mover assembly using at least one of the magnetic sensor signal and the second sensor signal.

Abstract: An exemplary stage assembly has movable stage mass and counter-mass. A stage motor is coupled to the stage mass and counter-mass such that stage-mass motion imparted by the stage motor causes a reactive motion of the counter-mass counter to the motion of the stage mass. At least one trim-motor is coupled to the counter-mass. A control system commands the trim-motor to regulate movement of the counter-mass in reaction to stage-mass motion. A PI feedback controller receives the following-error of the counter-mass and generates corresponding center-of-gravity (CG) force commands and trim-motor force commands to the trim-motor(s) to produce corrective counter-mass motion. A trim-motor force limiter receives trim-motor force commands and produces corresponding limited trim-motor force commands that are fed back as actual CG force commands to the feedback controller to modify integral terms of the feedback controller according to the limited trim-motor force commands.

Abstract: A method for determining a commutation offset for a mover (250A) of a mover assembly (220C) that moves and positions a stage (220A) relative to a stage base (220B) includes controlling the mover assembly (220C) in a closed loop fashion to maintain the position of the stage (220A) along a first axis and along a second axis with the stage (220A) levitated above the stage base (220B). The method also includes the steps of (i) directing current to a coil array (240) of the mover assembly (220C) so that the mover assembly (220C) imparts a disturbance on the stage (220A); and (ii) evaluating one or more forces generated by the mover assembly (220C) as a result of the disturbance on the stage (220A) created by the mover (250A). Further, a method for generating a compensation map (1402) includes sequentially directing a plurality of excitation signals to the control of the mover assembly (220C) and determining the control commands that result from the plurality of excitation signals.

Abstract: Methods are disclosed for calibrating a force constant of a movable stage. In an exemplary method, in first and second preliminary pre-stepping motions of the stage, a baseline force and a calibration force, respectively, as exerted by the stage are measured. From a force-variation ratio of the baseline force and calibration force an inverse closed loop factor is estimated. In at least one subsequent pre-stepping motion of the stage before a respective use of the stage for holding an object, a residual force-variation ratio is estimated, a force-compensation factor is updated from the residual force-variation ratio, and a respective force-variation coefficient is determined from the force-compensation factor.

Abstract: A stage mover for moving a stage relative to a stage base includes a conductor assembly and a magnet assembly. The conductor assembly is coupled to the stage base and a plurality of coil units with each coil unit having one or more coils. Each of the coils has a coil width. The magnet assembly interacts with the conductor assembly and includes a plurality of spaced apart magnet arrays. Each of the magnet arrays is spaced apart from each adjacent magnet array by an array gap that is at least equal to the coil width so that independent and symmetric magnetic flux distribution can be achieved for each of the magnet arrays.

Abstract: According to an aspect of the present invention, an apparatus includes a stage, at least a first coil, at least a first magnet, a plurality of Hall sensors, and a stage position estimation module. The first coil is included in a coil array that is a part of a coil arrangement. The first magnet is configured to cooperate with the first coil to form a motor that drives the stage. The dynamics model arrangement obtains a current command provided to the first coil and provides a first signal based on the current command. The Hall sensors are included in the coil arrangement, and are configured to measure a flux that includes a magnetic component and a coil component. The stage position estimation module is configured to obtain the flux and the first signal, and to process the flux and the first signal to estimate a position of the stage.

Abstract: According to one aspect, an apparatus includes a stage, a motor to move the stage, an amplifier, and a controller. The motor has at least a first coil and a second coil, and the amplifier is configured to selectively provide current to either the first coil or the second coil. The controller is configured to control force generated by the motor. When moving the stage, the controller controls the motor force by using the amplifier to provide current to the first coil, smoothly reducing a force generated by the first coil before the stage moves to a predetermined switching location so that the coil is generating substantially no force at the switching location, switching the amplifier so that the amplifier provides current to the second coil, and smoothly increasing a force generated by the second coil after the stage moves past the predetermined switching location.

Abstract: According to one aspect of the present invention, a stage apparatus includes a first stage, a first magnet arrangement, and a stator arrangement that includes a first coil having a first width. The first magnet arrangement is associated with the first stage, and includes a first quadrant and a second quadrant or, more generally, a first sub-array and a second sub-array. The first quadrant has at least one first magnet arranged parallel to a first axis, and the second quadrant has at least one second magnet arranged parallel to a second axis. The first quadrant is adjacent to the second quadrant relative to the first axis, and is spaced apart from the second quadrant by a distance relative to the second axis. The stator arrangement is configured to cooperate with the first magnet arrangement to drive the first stage.

Abstract: A method for determining a commutation offset for a mover (250A) of a mover assembly (220C) that moves and positions a stage (220A) relative to a stage base (220B) includes controlling the mover assembly (220C) in a closed loop fashion to maintain the position of the stage (220A) along a first axis and along a second axis with the stage (220A) levitated above the stage base (220B). The method also includes the steps of (i) directing current to a coil array (240) of the mover assembly (220C) so that the mover assembly (220C) imparts a disturbance on the stage (220A); and (ii) evaluating one or more forces generated by the mover assembly (220C) as a result of the disturbance on the stage (220A) created by the mover (250A). Further, a method for generating a compensation map (1402) includes sequentially directing a plurality of excitation signals to the control of the mover assembly (220C) and determining the control commands that result from the plurality of excitation signals.

Abstract: Embodiments of the invention compensate for one or more effects of a stage motor in a precision stage device. A feedforward module receives an input signal corresponding to the effect of the motor and generates a feedforward control signal that can be used to modify a motor control signal to compensate for the effect of the motor. In some embodiments, a control system is provided to compensate for a back-electromotive force generated by a motor, while in other embodiments, a control system may compensate for an inductive effect of a motor. Embodiments of the invention may be useful in precision stage devices, for example, lithography devices such as steppers and scanners.

Abstract: A stage assembly for positioning a device includes: (i) a stage that retains the device; (ii) a base; (iii) a mover assembly that moves the stage along a first axis, along a second axis, and along a third axis relative to the base; (iv) a magnetic sensor system that monitors the movement of the stage along the first, second and third axes, the magnetic sensor system generating a magnetic sensor signal; (v) a second sensor system that monitors the movement of the stage along the first, second and third axes, the second sensor system generating a second sensor signal; and (vi) a control system that controls the mover assembly using at least one of the magnetic sensor signal and the second sensor signal.

Abstract: A stage assembly (220) that moves a work piece (200) about a first axis and along a first axis includes a first stage (238), a second stage (240) that retains the work piece (200), a second mover assembly (244), a measurement system, and an initialization system (1081A). The second mover assembly (244) moves the second stage (240) relative to the first stage (238) about the first axis. The measurement system (22) monitors the position of the second stage (240) about the first axis when the second stage (240) is positioned within a working range about the first axis. The initialization system (1081A) facilitates movement of the second stage (240) about the first axis when the second stage (240) is rotated about the first axis outside the working range. The second mover assembly (244) can include a mover (255) and a dampener (410) that reduces the transmission of vibration from the first stage (238) to the second stage (240).

Abstract: Stage assemblies and control methods are disclosed. An exemplary assembly includes a first stage and first and second controllers. The first controller feedback-controls the first stage according to a respective parameter vector. The second controller controls the first stage by feed-forward control, according to a respective parameter vector. The controllers perform iterative feedback tuning IFT, including minimization of a cost-function of the parameter vectors from the first and second controllers. The second controller receives data including first-stage trajectory, and the first controller receives data including first-stage following-error. A suitable application of the assembly is in a microlithography system or other high-precision system.

Abstract: According to one aspect, a method for controlling a stage that is a part of a stage apparatus and is coupled to a voice coil motor (VCM) and an EI-core actuator arrangement includes driving the stage, identifying a frequency associated with the stage, and determining whether the frequency is below a frequency setpoint. The method also includes providing a first control force on the stage using the EI-core actuator arrangement when it is determined that the frequency is below the frequency setpoint, and providing the first control force on the stage using the VCM when it is determined that the frequency is not below the frequency setpoint.

Abstract: According to one aspect of the present invention, a stage apparatus includes a first stage, a first magnet arrangement, and a stator arrangement that includes a first coil having a first width. The first magnet arrangement is associated with the first stage, and includes a first quadrant and a second quadrant or, more generally, a first sub-array and a second sub-array. The first quadrant has at least one first magnet arranged parallel to a first axis, and the second quadrant has at least one second magnet arranged parallel to a second axis. The first quadrant is adjacent to the second quadrant relative to the first axis, and is spaced apart from the second quadrant by a distance relative to the second axis.