摘要:
A system to move a component in accordance with a setpoint profile including a plurality of target states of the component, each of the plurality of target states to be substantially attained at one of a corresponding sequence of target times, is presented. The system includes a displacement device to move the component according to the setpoint profile; a storage device containing a library of feedforward data; a signal generating part configured to identify a plurality of time segments of the setpoint profile that correspond to entries in the library of feedforward data, and access the entries in order to construct a feedforward signal; and a feedforward control system to control the operation of the displacement device by reference to the feedforward signal constructed by the signal generating part.
摘要:
A controller for a positioning device is constructed and arranged to receive a position signal indicative of a position of the positioning device, compare the position signal to a set-point signal indicative of a desired position of the positioning device to obtain an error signal, selectively modify the error signal based on the amplitude and the frequency content of the error signal to obtain a modified error signal, generate a control signal for controlling the positioning device on the basis of the modified error signal. The controller may be applied to control a positioning device in a lithographic apparatus.
摘要:
A controller for a positioning device is constructed and arranged to receive a position signal indicative of a position of the positioning device, compare the position signal to a set-point signal indicative of a desired position of the positioning device to obtain an error signal, selectively modify the error signal based on the amplitude and the frequency content of the error signal to obtain a modified error signal, generate a control signal for controlling the positioning device on the basis of the modified error signal. The controller may be applied to control a positioning device in a lithographic apparatus.
摘要:
A vibration isolation system isolates a body from its surroundings with respect to vibrations. The vibration isolation system includes active isolator devices that isolate and damp the body in unstable directions. However, such active isolators may exert damping forces not only in the unstable direction, but simultaneously in other stable directions due to mechanical coupling of the stable and unstable directions. As a result the damping and isolation in the other stable directions may be deteriorated due to the active isolation and damping. Employing modal decoupling, i.e. decomposing any vibration into independent directions, and isolating and damping in the independent directions, enables compensation of any vibration in an unstable direction without influencing the isolation and damping performance in any other, possibly stable, direction.
摘要:
A control system to control a position quantity of a movable object in dependency of signals provided by a sensor representing an actual position quantity of the moveable object, the control system being configured to provide a drive signal to an actuator which is able to apply forces to the moveable object, the control system including a set-point generator to provide a reference signal; a subtractor to provide an error signal, the error signal being the difference between the reference signal and the signals provided by the sensor; a control unit to provide a drive signal to the actuator in dependency of the error signal, wherein the control unit comprises a nonlinear controller to improve a low-frequency disturbance suppression, and wherein the control unit further includes a compensator to at least partially compensate the deterioration of the high-frequency behavior caused by the nonlinear controller.
摘要:
A control system configured to position a control location of a movable object in two or more degrees of freedom with respect to another object, including a set-point generator, a position quantity measurement system, a controller including a single input-single output controller for each degree of freedom to control a position quantity of the control location, each controller providing a control signal in logical coordinates on the basis of the error signal; and a gain scheduling device to provide centre-of-gravity control signals in centre-of gravity coordinates on the basis of the control signals, wherein the gain scheduling device includes a static and a dynamic relationship between logical coordinates and centre-of-gravity coordinates of the movable object.
摘要:
A stage system includes a movable stage, at least two encoder heads each constructed to provide an encoder signal representative of a position of the movable stage with respect to an encoder target structure, and a controller to control a position of the stage. The controller is provided with the encoder signals of each of the encoder heads. The controller is arranged to apply a weighting function to the encoder signals and to derive a position of the stage from the weighted encoder signals.
摘要:
A lithographic apparatus comprises an object table for receiving an object, an actuator for moving the object table and a handler for transferring the object to or from the object table. The apparatus is provided with a controller operable connected with the actuator and/or the handler. The controller is programmed and/or arranged to drive the actuator and the handler so as to provide that the object table and the handler substantially follow each other in a direction perpendicular to a transfer direction during transfer in the transfer direction of the object to or from the object table.
摘要:
In a lithographic apparatus, a feedforward transfer function of a control system is determined by: a) iteratively learning a feedforward output signal of the control system by iterative learning control for a given setpoint signal; b) determining a relation between the learned feedforward output signal and the setpoint signal; and c) applying the relation as the feedforward transfer function of the control system. A learned feedforward, which has been learned for one or more specific setpoint signals only, can be adapted to provide a setpoint signal dependent feedforward output signal. The learned feedforward can be made more robust against setpoint variations.
摘要:
In a method for controlling a positioning device, the positioning device has a stator and mover, the mover being movable relative to the stator; a position sensor configured to generate a position signal indicative of a position of the mover relative to the stator; a controller configured to receive the position signal, compare it to a setpoint signal to obtain an error signal, and generate a mover control signal on the basis of a signal component of the position signal, the controller having a variable gain. The positioning device, including the position sensor and the controller, defines a control loop. For error signals having a magnitude in a predefined range, the gain is selectively set to a value higher than a value for error signals having a magnitude outside the range.