Patent ID: 7209219

Claim:
A control system that controls a position of a mass by applying a control force to said mass in accordance with a desired mass acceleration, said control system comprising: a first input that receives a signal based on a desired position of said mass; a second input that receives a feedback signal indicative of an actual position of said mass; a comparator unit configured to determine a signal indicative of a difference between said desired mass position and said actual mass position; a control unit configured to produce a signal indicative of said control force based on said signal indicative of the difference between said desired mass position and said actual mass position; an estimator unit configured to calculate an estimated relation between said signal indicative of said control force and status information of said mass and generate an estimated mass signal, said status information comprising an indication of at least one of a position of said mass, a velocity of said mass, and an acceleration of said mass; and a third input that receives a feed-forward signal indicative of said desired mass acceleration, as modified by said estimated mass signal, and adds the feed-forward signal to the signal indicative of said control force to determine the control force that achieves the desired mass acceleration.