Experimental Investigation of Control Updating Period Monitoring In Industrial PLC-based Fast MPC: Application to The Constrained Control of a Cryogenic Refrigerator

TL;DR

This paper validates an adaptive control updating scheme in industrial MPC applied to a cryogenic refrigerator, demonstrating benefits of adjusting update frequency based on real-time cost function behavior.

Contribution

It provides industrial validation of an adaptive control updating period scheme in MPC, showing improved control performance for cryogenic refrigeration systems.

Findings

Less efficient optimizers can outperform more efficient ones when used with higher update frequencies.

Monitoring the cost function online helps optimize the control updating period.

Adaptive updating improves control effectiveness in industrial cryogenic systems.

Abstract

In this paper, a complete industrial validation of a recently published scheme for on-line adaptation of the control updating period in Model Predictive Control is proposed. The industrial process that serves in the validation is a cryogenic refrigerator that is used to cool the supra-conductors involved in particle accelerators or experimental nuclear reactors. Two recently predicted features are validated: the first states that it is sometimes better to use less efficient (per iteration) optimizer if the lack of efficiency is over-compensated by an increase in the updating control frequency. The second is that for a given solver, it is worth monitoring the control updating period based on the on-line measured behavior of the cost function.