Global predictive control: A unified control structure for decoupling setpoint tracking, feedforward compensation and disturbance rejection dynamics

Predictive control has now reached a mature level. However, a unification o f long-range predictive controllers, such as unified predictive control (UP C), generalised predictive control (GPC) and partial state model reference control (PSMRC) is still lacking. The paper presents global predictive cont rol (GlobPC), which unifies, for stable processes, these controllers. GlobP C is based on an internal model framework where three independent control c riteria are minimised: one for tracking, one for regulation and one for fee dforward. Using three criteria allows for the desired tracking to be obtain ed, and for regulation and feedforward to behaviours in an optimal way, whi le keeping them perfectly separated. Tho GlobPC structure also exhibits a c lean separation of the stochastic and deterministic parts of the control al gorithm. The state-space model representation is used for a more uniform an d easy programming of GlobPC for both single-input single-output and multip le-input multiple-output processes. An application to a pilot plant illustr ates the benefits of the method.