Gantry stages, consisting of two parallel acting drives, are a well-known example, where a significant interaction between all control systems’ in- and outputs is present due to structural coupling. Stability issues and therefore the limitation of the bandwidth of the position control can be a consequence of this effect. The adjustment of the systems mechanical properties using compliant joints, as well as the implementation of centralised control strategies are two possible approaches to overcome these issues and to improve the dynamic and static behaviour of the stage. Frequency domain methods for multivariable systems are used for controller tuning to consider properties like the controls’ time delay and high frequency mechanical eigenmodes, which are hard to model otherwise.
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