Identifying and suppressing unknown disturbances to dynamical systems is a
problem with applications in many different fields. In this Letter, we present
a model-free method to identify and suppress an unknown disturbance to an
unknown system based only on previous observations of the system under the
influence of a known forcing function. We find that, under very mild
restrictions on the training function, our method is able to robustly identify
and suppress a large class of unknown disturbances. We illustrate our scheme
with an example where a chaotic disturbance to the Lorenz system is identified
and suppressed.Comment: 9 pages, 9 figures (including supplemental material