Robust Mixed H₂/H∞ Model Predictive Control for Cyber-Physical Systems With Input Saturation and Energy-Bounded Disturbance

A robust model predictive control (RMPC) framework is proposed for nonlinear cyber-physical systems (CPSs) with input saturation and energy-bounded disturbance in this article. The coexistence of Lipschitz nonlinearity and actuator saturation remains a challenging problem in controller design. In our article, a major concern is to address the incorporation of bipartite nonlinear characteristics and exogenous disturbance under RMPC scheme. Via the saturation relaxation and Lipschitz condition, the conversion of a tractable linear matrix inequalitie-constrained problem is proposed in a less conservative way. For the purpose of enhancing the robustness and disturbance rejection, the proposed RMPC framework is associated with mixed <tex-math notation="LaTeX">H₂</tex-math> / <tex-math notation="LaTeX">H∞</tex-math> requirements. In particular, the algorithm is then cast into minimizing the upper bound of infinite-horizon cost function, and it is updated online for the linear control law. The computational feasibility is proved recursively, which is the key point in the practical implementation. Also, both the closed-loop stability and performance of CPS are derived. Eventually, the laboratory tank and reactor–separator process are presented to verify and illustrate the effectiveness of the proposed RMPC with mixed <tex-math notation="LaTeX">H₂</tex-math> / <tex-math notation="LaTeX">H∞</tex-math> performance.