This paper is concerned with the development of a control system for tracking of a desired temperature-time profile for accelerated cooling processes in hot rolling of steel. Control of temperature during cooling is essential for achieving desired mechanical and metallurgical properties of steel. The cooling process is represented by the heat equation in Lagrangian coordinates which is approximated by a set of ordinary differential equations. The control variable is the velocity of coolant water flow. Motivated by the fact that in many steel industries water flow is adjusted to some fixed velocity based on experience and heuristics, we assume that the control variable, water jet velocity, be a constant time invariant parameter. Gamkrelidze minimum principle is used to determine the optimal jet velocity for the desired temperature tracking. The results are illustrated by simulation examples.
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