PREDICTIVE CONTROL OF SHEET-FORMING AND FILM-FORMING PROCESSES

A constrained infinite-horizon model-predictive controller is advocate d to improve product properties from sheet- and film-forming processes by feedback control; the proposed model structure captures the main c haracteristics of the process, including the scanning sensor and large time delay. Model parameters are identified from process data, and sy mmetry is enforced to improve the parameter estimates. The film thickn ess is estimated from sparse measurements using a periodic Kalman filt er. The covariances of the estimates are used to evaluate scanning pat terns. Integrating disturbance models are used to achieve offset free control. Detectability conditions are presented for both models to ens ure that the disturbances can be estimated from the measurement. Once the state of the film is reconstructed adequately from the measurement , a control strategy can be implemented to improve film properties. On e important control contribution is to enable the controller to handle hard constraints on the actuators without clipping the controller out put signal. The target-tracking problem is discussed, and the uniquene ss of the steady-state solution is established. By simulations an outp ut disturbance model is compared with a measured input disturbance mod el.