Event-triggered economic MPC with relaxed contractive constraints

This paper proposes a novel event-triggered economic model predictive control (EMPC) scheme of constrained nonlinear systems. Some auxiliary positive-definite functions at economic optimal equilibrium points are defined for economic performance functions that are generally non-convex and non-positive-definite. The optimal value function of the auxiliary function is used to design an adjustable stability constraint which is imposed on the original EMPC optimization problem. The design of the contractive constraint can avoid Zeno behaviors during the triggered process. Especially, the event-triggered condition is designed by relaxed contractive constraint and the updated control laws. Sufficient conditions guaranteeing the recursive feasibility and stability of the EMPC are derived. Finally, the effectiveness of the obtained results is illustrated by a simulation example of a continuously stirred tank reactor.