On Operating Envelope Protection Design for Nonlinear Discrete-time Systems

Abstract

This paper is concerned with the operating envelope protection design for a broad class of nonlinear discrete-time systems based on a Robust Control Invariant (RCI) set framework. Existing techniques for a direct design of a RCI set for a general system suffer from the computational intractability connected with the complexity of a system model and model dimension. For a nonlinear system with mild assumptions on its model here we use a suitably defined linear model with additive uncertainty confined in a finite set and its corresponding maximum RCI set. Robust constraints satisfaction for the original system is ensured for a pre-defined set of disturbance trajectories. The approach is based on a superposition of a nominal and perturbed dynamics, whereas the coupling effects between respective dynamics are encompassed with the additive uncertainty. The additive uncertainty set is estimated by employing the trajectories of disturbance and a system description. The presented approach is scalable with respect to the system dimension. A simple example from the wind energy field is used to illustrate the proposed method.