An optimal output feedback solution to the strip shape multivariable control problem

Abstract

The design of shape control systems for producing flat metal strip products is discussed. Static and dynamic models for a Sendzimir mill are described briefly. Optimal dynamic output feedback solutions are presented for the shape control system design. The optimal control solutions provide guidance on the best structure to be used for shape control. It is shown that by judicious choice of the performance criterion weighting matrices particularly simple controllers may be derived; dimension reduction by parameterisation is also shown to result in a simplification to the controller structure. The effect of nonlinearities in the actuators is discussed, a linear approximation being used for design purposes. A variety of simulation results are presented showing the transient response and the shape control performance of the multivariable system. The effect of mismatch is also demonstrated, that is, using the controller for a mill schedule other than the one for which it was designed