Acoustic-driven millimetric helical robot: ultrasonic synergistic manipulation in confined fluidic environment

2026-08-06

AI Summary

Millimeter-scale robots often suffer from poor controllability in confined biological fluids due to low efficiency of acoustic actuation. This work proposes a multi-acoustic-field cooperative driving strategy that, for the first time, integrates acoustic radiation force and acoustic streaming effects at the millimeter scale, overcoming the efficiency limitations of conventional acoustic actuation in biologically constrained environments. Through multiphysics simulations and experimental validation, the approach enables multi-degree-of-freedom controllable motion on horizontal, inclined, and vertical planes. Unidirectional and reciprocating navigation have been successfully demonstrated within ex vivo porcine venous vessels, significantly enhancing the robot’s maneuverability and control precision in biologically relevant confined settings.

Abstract

Acoustic field-driven manipulation provides a non-contact and non-invasive strategy for controlling microscale and nanoscale objects, yet its extension to millimeter-scale robots was limited by insufficient propulsion efficiency in confined biological environments. Here, a coordinated multi-acoustic-field approach is introduced, which harnesses the synergistic action of acoustic radiation forces and acoustic streaming flows to enable controlled locomotion of millimeter-scale helical robots and enhance propulsion. Multiphysics simulations captured the dynamics of millimeter-scale helical robots under combined acoustic fields, and experimental validation demonstrated their locomotion capabilities, including planar navigation, inclined climbing, and vertical motion. Semi-autonomous navigation experiments further confirmed that ultrasonic synergy substantially improved maneuverability. In vitro tests in porcine venous vessels demonstrated that coordinated acoustic fields supported both unidirectional and reciprocating motion under biologically relevant confinement. These findings provide mechanistic insight into scaling acoustic micromanipulation to the millimetre regime and support biomedical applications requiring versatile and controllable robotic mobility.

Problem

• acoustic manipulation
• millimeter-scale robot
• confined fluidic environment
• propulsion efficiency
• biomedical robotics

Innovation

• acoustic radiation force
• acoustic streaming
• millimeter-scale robot
• helical robot
• ultrasonic manipulation