Model Predictive Control with Prioritised Actuators* *Research supported by the EPSRC grant “Control for Energy and Sustainability”, EP/G066477/1.

Abstract

This paper deals with the control of systems for which there is a clear distinction between preferred and auxiliary actuators, the latter to be used only when the control error is large. Explicit MPC and exact penalty functions are used to show how $\ell_{asso}$-MPC can implement this idea. Two $\ell_{asso^{-}}$ MPC versions are reviewed, that allow the designer to impose a certain nominal operations zone, namely, a neighbourhood of the set-point in which the auxiliary actuators are never used. For the sake of brevity, the required procedures are shown only for version 1, but it is also discussed how they can be extended to version 2. Limitations due to the presence of constraints are also formalised. The $\ell_{asso}$-MPC version 1 can be used to embed an existing linear quadratic MPC, while $\ell_{asso}$-MPC version 2 can be used to obtain multiple levels of priority. The paradigm is demonstrated for version 1 through the control of the linearised lateral dynamics of a Boeing 747. In particular, the approach uses the spoilers only when the control error is larger than a desired threshold.