Online tuning of real-world plants is a complex optimisation problem that
continues to require manual intervention by experienced human operators.
Autonomous tuning is a rapidly expanding field of research, where
learning-based methods, such as Reinforcement Learning-trained Optimisation
(RLO) and Bayesian optimisation (BO), hold great promise for achieving
outstanding plant performance and reducing tuning times. Which algorithm to
choose in different scenarios, however, remains an open question. Here we
present a comparative study using a routine task in a real particle accelerator
as an example, showing that RLO generally outperforms BO, but is not always the
best choice. Based on the study's results, we provide a clear set of criteria
to guide the choice of algorithm for a given tuning task. These can ease the
adoption of learning-based autonomous tuning solutions to the operation of
complex real-world plants, ultimately improving the availability and pushing
the limits of operability of these facilities, thereby enabling scientific and
engineering advancements.Comment: 17 pages, 8 figures, 2 table