Robust IMMPC: An Offset-free MPC for Rejecting Unknown Disturbances
This work addresses output regulation for control systems, but appears incremental as it extends an existing MPC scheme to more general disturbances.
The authors tackled the problem of achieving offset-free control in the presence of unknown bounded disturbances by extending Internal Model MPC to handle disturbances not generated by the disturbance model, and validated it on a four-tank system.
Output regulation is the problem of finding a control input to asymptotically track reference trajectories and reject disturbances. This can be addressed by using the internal model principle to embed a model of the disturbance in the controller. In this work, we present a Model Predictive Control scheme to achieve offset-free control. To do so, we extend Internal Model MPC to general bounded disturbances that must not be generated by the disturbance model. We show recursive feasibility, constraint satisfaction, and provide convergence conditions for the optimal reachable output. The proposed controller is validated on a four-tank system.