A research paper by scientists at Beijing Institute of Technology presented a magnetic shaftless propeller-like millirobot (MSPM) that possesses the capabilities of rotating-based multimodal 3-dimensional motion and cargo transportation with untethered manipulation.
The research paper, published on Mar. 12, 2025 in the journal Cyborg and Bionic Systems.
In recent years, magnetic miniature robots have shown great potential in biomedical, environmental remediation, micro control and other fields, especially in thrombosis treatment, drug delivery, endoscopic examination and other fields, with important application value. However, most existing magnetic miniature robots can only perform well in specific environments. For example, some robots can achieve good motion performance in liquids, while others can efficiently move on solid surfaces, but it is difficult to have multiple motion modes or the ability to cope with multiple environments at the same time. In addition, fluid handling capabilities, especially precise control of fluid and particle transport, are crucial for medical and other biomedical applications. "Therefore, the goal of our study is to design and develop a magnetic shaftless propeller-like millirobot (MSPM) that can achieve multi-mode movements such as rolling, rolling, and swimming, and has fluid transport capabilities." said the author Yaozhen Hou, a researcher at Beijing Institute of Technology, "By combining shaftless propeller structure with magnetic drive technology, MSPM aims to break through the limitations of existing magnetic miniature robots in fluid manipulation and motion capabilities, providing a solution with broad application potential."
The main objective of this study was to design and manufacture a magnetic shaftless propeller-like millirobot (MSPM) capable of performing multimodal motion and fluid manipulation in various environments. To achieve this, the robot was designed to consist of two main components: the magnetic propeller part and the non-magnetic supporting part. The magnetic propeller part generates propulsion through the interaction with a rotating magnetic field, while the non-magnetic supporting part provides stability and support for the robot. The magnetic propeller part of the MSPM is made from a mixture of polydimethylsiloxane (PDMS) and neodymium-iron-boron (NdFeB) magnetic particles. The propeller design is inspired by a shaftless water pump propeller and is capable of generating effective propulsion in liquid environments. The propeller features three blades, each measuring 1.3 mm in height and 2 mm in width, with a 45° tilt angle. This design allows the robot to generate both movement and fluid transportation capabilities under the influence of a rotating magnetic field. The supporting part is made from Ecoflex 00-30 silicone rubber, designed in a ring shape with a diameter of 3.6 mm, a width of 2 mm, and a thickness of 100 micrometers. This part provides the necessary support while maintaining flexibility, enabling the robot to adapt to various motion modes.
The research demonstrates the successful development of the magnetic shaftless propeller-like millirobot (MSPM), which effectively integrates multimodal motion and fluid manipulation. Leveraging the interaction between the robot's inner propeller feature and external environments, the robot is capable of performing multiple adaptive motion modes, including rolling, propelling, and tumbling, in different terrains. In addition, the robot demonstrated directed fluidic transportation through a spinning-based pumping mechanism facilitated by its shaftless propeller structure. Experiments conducted in 3D-printed artificial tube highlighted the potential applications of this robot in complex biomedical environments, such as in the treatment of the vascular system and gastrointestinal tract. "We anticipate that the MSPM holds great potential as a minimally invasive device for thrombosis treatment and targeted medicine delivery." said Yaozhen Hou.
Authors of the paper include Yaozhen Hou, Shihao Zhong, Zhiqiang Zheng, Jiabao Du, Ruhao Nie, Qing Shi, Qiang Huang, and Huaping Wang.
This work was supported by the National Key Research and Development Program of China under grant 2023YFB4705400; the National Natural Science Foundation of China under grant numbers 62403056, 62088101, and 62222305; the Postdoctoral Fellowship Program of CPSF under grant BX20230459; and the Beijing Natural Science Foundation under grant 4232055.
The paper, "Magnetic Shaftless Propeller Millirobot with Multimodal Motion for Small-Scale Fluidic Manipulation" was published in the journal Cyborg and Bionic Systems on Mar. 12, 2025, at DOI: 10.34133/cbsystems.0235.
