Control apparatus and method for controlling a manipulator in respect of a microlithographic projection exposure apparatus

A method for controlling a manipulator to modify a parameter of a microlithographic projection exposure apparatus, the method comprising:

• generating a target for a travel variable for the at least one manipulator from a state characterization of the microlithographic projection exposure apparatus by optimizing a merit function, the merit function comprising a penalty term for taking account of a limit for a property of the microlithographic projection exposure apparatus, the penalty term formulated so that its function value prevents the limit for the property of the microlithographic projection exposure apparatus from being exceeded;
• and
• modifying the parameter of the microlithographic projection exposure apparatus via the at least one manipulator on the basis of the generated target for the travel variable,
• wherein the property of the microlithographic projection exposure apparatus for which the penalty term comprises a limit includes an imaging aberration of a projection lens of the microlithographic projection exposure apparatus.