Loop control system of wire rolling mill using H/sup infinity / control design method

An H/sup infinity / control design method was applied to the loop control of a wire rolling line. Specifying robust stability and disturbance suppression performance, H/sup infinity / controllers were obtained. Elements of their transfer matrices have the structure of the PID (proportional plus integral plus derivative) controller. Simulations were used to compare these controllers and the conventional one. Performance is found to be improved in the loop control system by H/sup infinity / controllers. Control performance is maintained even when material size is changed. Robustness with respect to change of rolling condition was obtained.<<ETX>>