Hierarchical Optimisation for a Reheat Furnace and Rolling Mill System

Abstract The hierarchical control of a steel hot plate system is examined. The system is decomposed into three separate subsystems consisting primarily of the reheat furnaces, roughing mill and finishing mill, respectively. Using the interaction balance and model coordination approaches, alternative multilevel techniques are proposed for the optimal control of the decomposed system where the aim is to maximise throughput and minimise fuel and power consumption. Paying particular attention to the model coordination approach, which has some advantages of on-line feasibility, simulation results are presented; and a semi-pilot scale plant investigation is described where a reheat furnace is represented by an electrically heated traveling load oven and a rolling mill is simulated within a process control computer.