Effect of model errors on the closed orbit correction at the SIS18 Synchrotron of GSI

The influence of model errors on the closed orbit correction for the SIS18 synchrotron at GSI has been simulated. The systematic model drift over the ramp due to the transition of triplet to doublet quadrupole configuration and the non-systematic tune shifts due to image charge and beta beating are considered. The study is aimed to draw hints for the robust stability requirements of the closed orbit feedback controller against model mismatch.