An Algorithm of Heating Temperature of Billets in the Continuous Furnace

Abstract

The difference equation approach is mostly used in the computer control of heating temperature of billet in the furnace. This approach is not suitable for the on-line prediction calculation as it requires a vast amount of recursive computation. The form of the difference equation used in this approach does not make it possible to directly apply various modern control strategies to the control aspect.
To avoid these problems it is desired to have a linear constant equation which relates the temperature of billet as output and the temperature of furnace as input. Theoretical derivation is impossible, because thermal constants are nonlinear and heat transfer coefficient is not constant over the whole furnace.
A new algorithm is proposed in this paper. The furnace is divided into several zones in which a linear constant input-output equation can be obtained. Intervals are determined not apriori but from the operating data. The boundary of intervals is fixed according to the behaviour of recursive estimates of parameters.
The proposed algorithm has been applied to the existing furnace with satisfactory results. The predicted temperature of billet agree with the observed data with good accuracy.