Non-fragile Robust Control for a High-Purity Distillation

The low order controllers by employing model reduction to high order controllers about design of normal robust control for distillation are fragility. It can´t guarantee good robust performance. Even the increasing oscillation of the system occurs when the distillation is perturbed in the design specification. A design method of the non-fragile robust mu-synthesis PI controllers that are not used model reduction is presented. It is also suggested that the design of the non-fragile robust performance can be formulated as a mu-synthesis problem. The perturbations of the controllers can be converted those of the controlled members by the transformation of the mathematical model. In order to simplify the solution, the simple expression of the PI controllers about the MIMO distillation system is studied. The selections of the weighting functions are discussed and the non-fragile robust mu-synthesis PI controllers are solved. The simulation results show that the non-fragile robust performance of the system to the non-fragile robust mu-synthesis method is the best of those to non-fragile robust H^infin design and mu-synthesis about model reduction