Reversed frame normalizing design of a decentralized control system for a binary distillation column

The reversed frame normalizing design technique of Y.S. Hung and A.G.F. MacFarlane (1982) is modified to yield decentralized controllers. This modified technique is applied to a binary distillation control problem. It results in a simple decentralized control law that proves to be superior to conventionally designed PI-controllers and no worse than higher-order decentralized controllers based on constrained H ₂-minimization. The basic ideas of this linear multivariable design method are summarized. Then, modifications necessary to achieve (block) diagonal controller transfer-function matrices are outlined. Implications for achievable closed-loop performance are discussed. They are seen to follow directly from the theory of optimal matrix scaling