MPC tracking under time-varying polytopic constraints for real-time applications

This paper presents a real-time MPC-based tracking strategy for linear systems subject to time-varying constraints. The framework is quite general since time-varying constraints in the state and in the input are considered. To handle the problem, a polytopic invariant set computed off-line is homogeneously dilated and contracted on-line to fit the polytopic time-varying constraints, and used as an admissible terminal set constraint to guarantee stability and convergence in the tracking task. The on-line cost of the homothetic invariant set computation is negligible and allows dealing with tracking problems for real-time applications.