Patent ID: 8619232

Claim:
A method for damping motion of an object in two or more degrees of freedom using a multivariable controller, the multivariable controller comprising a position quantity measurement system configured to measure a position quantity of the object at two or more measurement locations, a controller configured to provide a control signal to two or more actuators mounted to the object on the basis of the measured position quantity at the two more measurement locations, the controller comprising an extractor configured to extract for at least one degree of freedom from the measured position quantity at the two or more measurement locations a measurement signal for two different dynamic modes of the object, and a controller unit for each dynamic mode, the control signal for the two or more actuators being based on output signals of the controller units of each dynamic mode of at least one degree of freedom, the method comprising: measuring the position quantity at each of the two or more measurement locations; extracting, for each degree of freedom, from the measured position quantity at each of the two or more measurement locations a measurement signal for each of the two different dynamic modes; for each of the two different dynamic modes of each said degree of freedom, supplying the measurement signal of a dynamic mode to a respective controller unit of the controller associated with the respective dynamic mode, the controller unit providing for each dynamic mode an output signal on the basis of the respective measurement signal; and providing the control signal to the two or more actuators, the control signal being based on output signals of one or more controller units.