Lithographic apparatus controller system

A controller system configured to control a plant, comprising:

• a feedforward controller configured to provide, based on a reference state signal, a feedforward signal to the plant;
• and
• a feedback controller system configured to provide a feedback signal to the plant, based on a difference between the reference state signal and a plant state signal representing an actual state of the plant,
• wherein the feedback controller system comprises an integrator, a trajectory generator, and a selector configured to selectively output into the feedback signal to the plant one of a trajectory generator output signal generated by the trajectory generator and an integrator output signal generated by the integrator,
• wherein the feedback controller system is configured to operate as a function of the reference state signal in a first control mode or a second control mode.
• wherein the feedback controller system is configured to, in the first control mode, operate the selector to select the trajectory generator output signal generated by the trajectory generator, and
• wherein the feedback controller system is configured to, in the second control mode, operate the selector to select the integrator output signal generated by the integrator.