Control schemes for a cyclically operating aluminum extruder plant

Productivity and product quality of aluminium manufactured by extrusion are enhanced by control of the exit temperature of the extruded bars. Problems encountered. In the design of a suitable control system and control schemes tried hitherto are described. A new control scheme which improves the control from cycle to cycle by iteratively optimizing a quality index is presented. It is shown how an advantage offered by iterative control, viz. the feasibility of non-causal filtering, can be exploited to avoid time-lags inherent in smoothing algorithms. A comparison of the performance of the presented control schemes and results obtained in field-tests are presented