Optimal and Adaptive Control of Strip Temperature for a Heating Furnace in C.A.P.L.

Abstract

The strip temperature control for a heating furnace is discussed. A new control has been developed at Nagoya Works. It is based on a new dynamic mathematical model which employs the fuel flow rate as a control signal. The unique feature of this control is a new control strategy, called the optimal preview control, to cope with future set changes (changes of strip width, thickness, or heat pattern). It determines the production line speed and the target trajectory of the strip temperature for future set changes. In order to control the temperature to this target trajectory, a self-tuning control with pole-placement was modified and introduced into a dynamic follow-up control. The plant parameters are estimated on-line by a least squares estimation with multiple and variable forgetting factors. The control has been successfully applied to an actual operating plant and has achieved excellent results.