Stabilizing Tube-Based Model Predictive Control: Terminal Set and Cost Construction for LPV Systems (extended version)

TL;DR

This paper introduces a stabilizing tube-based MPC method for LPV systems using periodically contractive terminal sets and costs, reducing computational complexity and ensuring stability.

Contribution

It proposes a novel periodic homothetic tube parameterization and a tractable LPV MPC algorithm with guaranteed stability and recursive feasibility.

Findings

Lower computational effort for terminal set construction.

Guaranteed asymptotic stability of the control scheme.

Efficient LP-based online optimization with linear complexity.

Abstract

This paper presents a stabilizing tube-based MPC synthesis for LPV systems. We employ terminal constraint sets which are required to be controlled periodically contractive. Periodically (or finite-step) contractive sets are easier to compute and can be of lower complexity than "true" contractive ones, lowering the required computational effort both off-line and on-line. Under certain assumptions on the tube parameterization, recursive feasibility of the scheme is proven. Subsequently, asymptotic stability of the origin is guaranteed through the construction of a suitable terminal cost based on a novel Lyapunov-like metric for compact convex sets containing the origin. A periodic variant on the well-known homothetic tube parameterization that satisfies the necessary assumptions and yields a tractable LPV MPC algorithm is derived. The resulting MPC algorithm requires the on-line solution of a single linear program with linear complexity in the prediction horizon. The properties of the approach are demonstrated by a numerical example.