A Multistep, Newton-Type Control Strategy for Constrained, Nonlinear Processes

For linear processes, QDMC has proven to be an effective way of systematically handling both input and output process constraints. This note describes an analogous extension of QDMC for nonlinear, constrained Processes. Based on Newton-type methods implemented in a moving horizon framework, a multi-step algorithm is derived that solves a single quadratic program (QP) over each time horizon. Sufficient stability properties can be invoked through the concept of descent directions, and these conditions can also be checked on-line. Finally, the method is illustrated on a small reactor example with state and input time delays.