Abstract: A lithographic apparatus includes a movable object and a control system to control the position of the movable object. The control system includes a position measurement system configured to measure the position of the movable object, a comparative unit configured to generate a servo error signal by subtracting a position signal representative of an actual position of the movable object from a reference signal, a control unit configured to generate a first control signal based on the servo error signal, a feed-forward unit configured to generate a feed-forward signal based on the reference signal, an addition unit configured to generate a second control signal by adding the first control signal and the feed-forward signal, and an actuator unit configured to actuate the movable object. A gain of the feed-forward unit is dependent on the position of the movable object.

Abstract: A lithographic apparatus includes a movable object and a control system to control the position of the movable object. The control system includes a position measurement system configured to measure the position of the movable object, a comparative unit configured to generate a servo error signal by subtracting a position signal representative of an actual position of the movable object from a reference signal, a control unit configured to generate a first control signal based on the servo error signal, a feed-forward unit configured to generate a feed-forward signal based on the reference signal, an addition unit configured to generate a second control signal by adding the first control signal and the feed-forward signal, and an actuator unit configured to actuate the movable object. A gain of the feed-forward unit is dependent on the position of the movable object.

Abstract: A motion control system is presented. In an embodiment of the invention, the motion control system compares a motion profile setpoint generator configured to generate a set of profile setpoint signals including a position profile setpoint signal and additional profile setpoint signals. The feedforward controller generates a feedforward signal by summing the additional profile setpoint signals, the additional profile setpoint signals being multiplied by a respective coefficient. The motion control system is configured to (a) select an initial setting of the respective coefficients, (b) cause the motion profile setpoint generator to generate a set of profile setpoint signals so as to execute a motion profile, (c) measure an error between the position profile and an output position signal, and (d) update the respective coefficients by adding a product of the error and a respective learning gain thereto. In an implementation, standard motion controllers can be used.

Abstract: A motion control system is presented. In an embodiment of the invention, the motion control system compares a motion profile setpoint generator configured to generate a set of profile setpoint signals including a position profile setpoint signal and additional profile setpoint signals. The feedforward controller generates a feedforward signal by summing the additional profile setpoint signals, the additional profile setpoint signals being multiplied by a respective coefficient. The motion control system is configured to (a) select an initial setting of the respective coefficients, (b) cause the motion profile setpoint generator to generate a set of profile setpoint signals so as to execute a motion profile, (c) measure an error between the position profile and an output position signal, and (d) update the respective coefficients by adding a product of the error and a respective learning gain thereto. In an implementation, standard motion controllers can be used.

Abstract: In a control system, a shock resulting in an error is detected. The detection of the shock initiates compensation to reduce the error. The compensation depends on corrective data contained in a memory of the player. The error while being reduced by the compensation is measured, and the corrective data is updated depending on the measured error.