Digital control in iron- and steelmaking processes

Abstract

There are two kinds of processes involved in steelmaking. One is well defined by a mathematical model, the other cannot be defined because of parameter uncertainty, nonlinearity and large dead time. In this paper, model-based controls such as optimal control and observer based control are shown to be useful in rolling mills and roll speed control systems. This paper presents a new digital control system called “Holon-type hybrid control”, a model-free control which is a useful method for controlling heat processes, for example. Such plants are well known to possess time-varying parameter properties (nonlinear processes) and large dead time. The model-free control system, which is a hierarchical and multirate sampling control method, is confirmed to be effective in a complicated heat plant with parameter uncertainty and time delay by applying the control system to our Organic Rankin Cycle System heat recovery plant experiment in the steelmaking process.