"H-infinity Control for Molten Steel Level in Continuous Caster"

Hiroshi Kitada, Computer System Technology Department, System Engineering Division, Sumitomo Metal Ind.

We have applied H-infinity controller to the molten steel level control in continuous caster. The features of our design of the H-infinity controller is: In the H-infinity controller synthesis, the conventional mixed sensitivity design use two weight functions, one to shape the sensitivity S(s) and onother to shape the complementary sensitivity T(s). But we used four functions, two for the two disturbance signals, and two for the two outputs to evaluate. As a result, we have another degree of freedom to adjust the weight functions to shape S and T. We used the another freedom to shape them in the intermediated freequency range.