Frequency-shaped cost functionals for decentralized systems

The linear-quadratic (LQ) design methodology with frequency-shaped performance indices is extended to decentralized systems. This provides the opportunity to consider different frequency-related constraints in each channel. To obtain decentralized controllers, frequency weightings are included only on the outputs and the inputs. This controller design methodology permits the designer to have some frequency-domain design constraints in the LQ design setting. Inclusion of decentralized static and dynamic output feedbacks in the proposed formulation is examined. To illustrate the design approach, two nontrivial examples are given. The first is a model for the NASA mast flight system, and the second is a suspended beam developed in-house for experimentation