Acoustic-driven millimetric helical robot: ultrasonic synergistic manipulation in confined fluidic environment
Organizations: State Key Laboratory of Industrial Control Technology and the Institute of Cyber-Systems & Control, Zhejiang University, Hangzhou 310027, Zhejiang, China · Huzhou Institute of Zhejiang University, Huzhou Key Laboratory of Robot System Integration and Intelligent Equipment, Huzhou 313099, Zhejiang, China · State Key Laboratory of Advanced Drug Delivery and Release Systems, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310058, Zhejiang, China · School of Science, Huzhou Normal University, Huzhou 313000, Zhejiang, China · School of Intelligent Manufacturing and Elevator, Huzhou Vocational and Technical College, Huzhou 313099, Zhejiang, China · The Huzhou Key Laboratory of Robot System Integration and Intelligent Equipment, Huzhou2026 313099, Zhejiang, China · Zhejiang Provincial Engineering Research Center for Intelligent Mobile Unmanned Systems Technology and Huzhou Key Lab for Autonomous Systems, Huzhou Institute of Zhejiang University, HuzhouAug 313000, Zhejiang, China
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.