Solutions for ratio control of nonlinear blend processes

This paper analyses classic solutions and proposes a precise structure solution for the ratio control of nonlinear processes blend stations. The main feature of the proposed structure is to give a good ratio performance for both set-point changes and load disturbances that might occur in any one of the loops. For two or more included loops a nonlinearity compensator or multiple model structure is proposed. The main advantages consist in a very simple procedure for nonlinearity determination and a classic tuning procedure for each of the controllers, suitable for industrial applications. Proposed control structure performances were tested on real time control.