Direct derivative feedforward vibration compensation system
AssigneeNikon Corporation
InventorsYi-Ping Hsin, Susumu Isago, Kazuo Masaki, Bausan Yuan
Life of this patent
Estimating the term…
Abstract
Methods and apparatus for providing vibration compensation using position measurements are disclosed. According to one aspect of the present invention, a method of compensating for vibrations of an object includes obtaining a plurality of position measurements associated with the object. The method also includes processing the plurality of position measurements to determine a derivative acceleration, and determining a compensatory force to counteract the vibrations of the object. Determining the compensatory force includes using the derivative acceleration. Finally, the method includes applying the compensatory force to the object.
Claims20
A method of compensating for vibrations of an object, the method comprising:
- obtaining a plurality of position measurements associated with the object;
- processing the plurality of position measurements to determine a derivative acceleration, wherein processing the plurality of position measurements to determine the derivative acceleration includes deriving at least one velocity from the plurality of position measurements and deriving the derivative acceleration from the at least one velocity;
- determining a compensatory force to counteract the vibrations of the object, wherein determining the compensatory force includes using the derivative acceleration;
- and
- applying the compensatory force to the object, wherein the deriving the at least one velocity is performed by a first derivative controller and deriving the derivative acceleration is performed by a second derivative controller.
An apparatus for compensating for vibrations of an object, the apparatus comprising:
- a position sensing arrangement, the position sensing arrangement being configured to measure at least a first position of the object at a first time, a second position of the object at a second time, and a third position of the object at a third time;
- a derivative control arrangement, the derivative control arrangement being configured to derive at least a first derivative velocity using the first position, the second position and the third position, the derivative control arrangement further being configured to derive at least a first derivative acceleration using at least the first derivative velocity;
- and
- a compensation arrangement, the compensation arrangement being arranged to determine a compensation force to compensate for the vibrations of the object using at least the first derivative acceleration, wherein the compensation arrangement is still further arranged to cause the compensation force to be applied to the object.
An apparatus of comprising:
- an object, the object being subjected to vibrations;
- a driver, the driver being configured to apply a force to the object;
- a position sensing arrangement, the position sensing arrangement being configured to measure positions of the object at different times, the positions of the object including a first position, a second position, and a third position;
- and
- a control arrangement, the control arrangement being arranged to determine the force to be applied to the object to compensate for the vibrations, wherein the control arrangement is arranged to determine the force by processing the positions, and wherein the control arrangement includes a first derivative controller and a second derivative controller, the first derivative controller being arranged to construct at least a first velocity of the object using the positions, the second derivative controller being arrange to construct at least a first acceleration of the object using at least the first velocity.
Dependencies are inferred from the claim text.