1. A process control system for controlling at least one process actuator, the process control system comprising: a first process model for driving the at least one process actuator in such a manner that, from at least one process desired variable fed to the first process model, at least one process desired manipulating variable is generated for driving the at least one process actuator; a second process model which generates a process actual variable from at least one process actual manipulating variable of the at least one process actuator; and a process element for generating a comparison process actual variable; wherein the first process model can be mapped by inverting the second process model; wherein a process actual variable difference which is formed from the process actual variable and the comparison process actual variable is fed via a control unit to the first and the second process model; and wherein the process element is configured as a third process model with higher process reproduction precision than the first and second process models, and includes at least one non-invertible process component.