Abstract:
A control device configured to determine a primary first drive signal, based on a first error signal representing a difference between desired and measured positions of a first body, for driving a positioner driving the first body; determine a primary second drive signal, based on a second error signal representing a difference between desired and measured positions of a second body, for driving a positioner driving the second body; determine, based on the second error signal, a secondary first drive signal for driving the first body positioner; determine, based on the first error signal, a secondary second drive signal for driving the second body positioner; combine the primary and secondary first drive signals and combine the primary and secondary second drive signals; and output the combined first and second drive signals to the respective positioning devices.
Abstract:
The invention relates to a control system comprising a controller arranged to provide an output signal on the basis of an input signal. The controller comprises a linear integrator, a linear gain and a selector. The linear integrator is arranged to provide a first control signal. The linear gain is in parallel to the linear integrator and is arranged to provide a second control signal. The selector is arranged to switch between an integrator mode in which the first control signal is used as the output signal of the controller and a gain mode in which the second control signal is used as the output signal of the controller. The selector is arranged to switch to the integrator mode when the value of the second control signal passes zero, and to switch to the gain mode when: eu