Three-stage near-optimum design of nonlinear-control processes

A systematic near-optimum design technique for the control of nonlinear-control processes is presented. The method consists of three stages. In the first stage, called `subprocess decoupling¿, coupling is neglected between two or more subsystems, thus reducing the process to a set of weakly coupled subprocesses. The second stage is to represent each subprocess by `slow¿, `basic¿ and `fast¿ models, and is called `time-scale decoupling¿. The third stage eliminates slow and fast variables, and obtains a near-optimum control for the basic subsystem. The method is applied to a coiler process common in continuous rolling mills.