Abstract
The paper considers the need for control systems in the hot and cold rolling of steel strip. It is not intended for steel specialists, but is a broad case study designed to illustrate two important points of general interest to control engineers.
(i) Every control loop is present in order to correct for some deviation from ideal behaviour in the plant or the plant inputs. This is a useful and systematic initial approach to the problem of designing the overall control system configuration for a particular process.
(ii) The need for each type of control implied in (i) can be minimised or eliminated by proper design of the plant or by proper choice of operational procedures. This is a quite general statement and it leads to the view: Control systems engineers should be involved in the planning and design of new plant, so that an economically wise choice can be made between expenditure on improved design and expenditure on improved control.
Three units of plant, which together constitute a closely linked production complex, are considered together and an analysis made of their potential for improvement by the application of control systems. Possible economic benefits are first listed and then reasons for deviation from ideal behaviour are discussed. Each deviation from ideal behaviour can be corrected either by changes in plant design or operation or by the application of improved control.
An outline is given of the types of control system required to correct deviations in this configuration. In particular, the problem of control of strip flatness is discussed since this is the most innovative part of the work.
Get full access to this article
View all access options for this article.