Sufficient LMI conditions for output feedback control problems

In this paper the authors present linear matrix inequality (LMI) conditions for output feedback control problems. The results based on sufficient conditions because they are dependent on the particular state-space representation used for describing the system. Nevertheless, the conditions are not sensitive to a certain class of state-space transformations, and if the control problem is feasible then there exists some state-space transformation leading the conditions to be necessary and sufficient for the problem. The authors approach can be used for designing decentralized controllers and is easily extended to H-2, H-infinity and mixed H-2/H infinity problems via standard LMI techniques. The continuous- and discrete-time cases are considered and numerical examples are given to illustrate the results.