EMPC Systems: Computational Efficiency and Real-Time Implementation

Abstract

In this chapter, three economic model predictive control (EMPC) schemes are presented that broadly address the issues of computational efficiency and real-time implementation. In the first section, a composite control structure featuring EMPC is presented for two-time-scale systems described by a class of nonlinear singularly perturbed systems. Owing to the fact that the dynamic models that describe such systems are inherently ill-conditioned, a composite control structure is well-conditioned which has computational advantages over the use of one centralized model-based controller formulated with the ill-conditioned model. The second section presents an application study of several distributed EMPC designs. For the chemical process example analyzed, similar closed-loop economic performance is achieved under distributed EMPC relative to that achieved under centralized EMPC. The last section presents a real-time implementation strategy for Lyapunov-based EMPC (LEMPC). The real-time LEMPC addresses potentially unknown and time-varying computational time for control action calculation. Closed-loop stability under this real-time LEMPC strategy is rigorously analyzed.