Invariant Set-Based Robust Softly Switched Model Predictive Control

It is common that an efficient constrained plant operation under full range of disturbance inputs requires meeting different sets of control objectives. This calls for application of multiple model predictive controllers each of them being best fit into specific operating conditions. It is inevitable then to switch between the controllers during the plant operation. A simple immediate hard switching may introduce unwanted transients and also it may not achieve robustly feasible controller operation. A soft switching strategy distributes the switching process over a certain time period and consequently it smoothes the transient processes and achieves the robust feasibility. The softly switched model predictive control scheme based on the invariant set theory is proposed for the additive set bounded and polytopic models of uncertainty. Simulation examples are given.