Characterizing the performance of the hydrodynamic trap using a control-based approach

Hydrodynamic trapping allows for the confinement and manipulation of small objects in free solution, away from solid boundaries and without the need for optical or magnetic fields. In order to achieve robust trapping over long time scales, it is imperative to evaluate trap performance using different control schemes and to understand the effect of system parameters on trap stability. In this work, we investigate the performance of a hydrodynamic trap actuated by varying combinations of proportion-integral-derivative controllers. We further develop a control-based model of the trap, and we characterize trap performance for a wide range of particle Peclet numbers and response times. Overall, an increased understanding of trap performance will facilitate the design of improved controllers to enable robust trapping under variable system parameters.