CONTROL SYSTEMS FOR EXTRUSION OR DRAWING PLANTS

A control system for an extrusion plant is constructed by, creating a mathematical model 58A of the plant by exciting the plant actuators, and establishing a mathematical relationship between the plant inputs and outputs, creating a mathematical disturbance model 60 to represent the differences between the plant inputs and the model outputs, using the mathematical model 58A and the disturbance model 60 to create a mathematical model base controller 62, and, using the mathematical model based controller to control the real extrusion plant. The establishment of the model based controller enables the plant to be controlled in a more efficient manner by correcting for the effects of disturbances produced while the plant is operating before the effect of these disturbances manifest themselves in the product at the downstream end of the plant. A method of constructing a fault deletion or detection system in which a fault is induced, a mathematical relationship between the fault and the extruder plant output is created, and the plant is monitored for an output characteristic indicative of the relationship, is also described.