Contactless Precision Steering of Particles in a Fluid inside a Cube with Rotating Walls

TL;DR

This paper presents a novel contactless particle manipulation method using rotating walls and a feedback control algorithm to precisely steer multiple particles in a fluid, with potential biomedical applications.

Contribution

It introduces a new control algorithm that uses flow generated by rotating disks to steer multiple particles simultaneously, integrating fluid dynamics with an optimization framework.

Findings

Successfully transported two beads to predefined locations in experiments.

Demonstrated robustness of the control method in simulations and physical device.

Enhanced precision in contactless particle manipulation for biomedical uses.

Abstract

Contactless manipulation of small objects is essential for biomedical and chemical applications, such as cell analysis, assisted fertilisation, and precision chemistry. Established methods, including optical, acoustic, and magnetic tweezers, are now complemented by flow control techniques that use flow-induced motion to enable precise and versatile manipulation. However, trapping multiple particles in fluid remains a challenge. This study introduces a novel control algorithm capable of steering multiple particles in flow. The system uses rotating disks to generate flow fields that transport particles to precise locations. Disk rotations are governed by a feedback control policy based on the Optimising a Discrete Loss (ODIL) framework, which combines fluid dynamics equations with path objectives into a single loss function. Our experiments, conducted in both simulations and with the physical device, demonstrate the capability of the approach to transport two beads simultaneously to predefined locations, advancing robust contactless particle manipulation for biomedical applications.