The role of model uncertainty in cross-directional control systems - Robustness must be included in controller design

The performance limitations imposed by model uncertainty for multivariable feedback control systems are well known. The goal of this work is to examin e these limitations in terms of cross-directional (CD) control, In CD contr ol, the model uncertainty places limitations on the spatial and dynamical c losed-loop bandwidths of a CD control system, which are independent of the feedback control law used. Industrial results are shown for two very differ ent CD processes.