Operator control activities in flexible manufacturing systems

Modern control systems often exhibit problems in switches between automatic and manual system control. One reason for this is the structure of the control system, which is usually not designed for this type of action. This article presents a method for splitting the control system into different control levels. By switching between these control levels, the operator can increase or decrease the number of manual control activities he wishes to perform while still enjoying the support of the control system. The structural advantages of the control levels are demonstrated for two types of operator activity; 1 control flow tracing; and 2 control flow alteration. These two types of operator activity can be used in such situations as when locating an error, introducing a new machine, changing the ordering of products or optimizing the production flow.