Recently, Chinese scientists have created a soft magnetic microrobot capable of various movement modes using neodymium magnets, Ecoflex, and a soft thin film. Scientists can control the microrobot’s movement, grasping, and transportation of tiny objects by manipulating external magnetic field parameters. This robot shows promise for potential applications in gastric examinations.
Structure of The Microrobot
Inspired by quadrupedal animals in nature, the microrobot consists of four ‘magnetic legs’ and a non-magnetic thin film body.
The four ‘magnetic legs’ are made of neodymium magnets and Ecoflex. The neodymium magnets provide magnetic properties to the ‘legs’, while Ecoflex makes them flexible. This allows the microrobot to move its four ‘magnetic legs’ alternately under the influence of an external magnetic field, achieving positional movement similar to quadrupedal animals in nature.
The manufacturing process of the robot has been significantly simplified through the use of high-precision 3D printing and casting techniques.
Mobility of the Microrobot
Using different driving magnetic fields, the robot can achieve multiple motion modes, such as crawling and rolling. A conical magnetic field is produced by superimposing a rotating magnetic field with a constant strength magnetic field. Under this conical magnetic field, the robot can alternately move its pairs of legs to crawl on a flat surface, similar to quadrupedal animals in nature.
Researchers conducted experiments by placing the microrobot in silicone oil with a viscosity comparable to human gastric fluid. They measured the deformation angle of the robot’s magnetic legs when applying magnetic fields of different strengths. The experimental results showed that the deformation angle of the robot’s legs increased with the increase in magnetic field strength, and the robot’s maximum moving speed could reach 3.9 mm/s.
Experiments also demonstrated that the robot could move forward and turn flexibly, following s-shaped and square-shaped trajectories set by the researchers. With precise control of magnetic field parameters, the microrobot could even climb up and down steps, each step being 1 mm high.
When tested at the bottom of a stomach model filled with grooves, the robot could fully utilize its multi-motion mode advantages. It could cross obstacles about 2.2 mm high, while for obstacles higher than this, the microrobot could overcome them using its rolling mode.
Object Transport Capability of the Microrobot
After proving the robot’s excellent obstacle-crossing ability, researchers conducted experiments to manipulate the robot to grasp small beads. Each bead was only 6 mm in diameter and weighed 127.3 mg, while the robot itself weighed 41.1 mg. Through the application of an external magnetic field, the robot could grasp and transport objects weighing up to three times its weight.
Applications of the Microrobot
This magnetically controlled soft robot has already demonstrated excellent mobility, obstacle-crossing ability, and target transport capability. Chinese scientists will further optimize the functions of this robot to achieve more efficient movement and grasping abilities. It shows promise for future applications in human gastric examinations and treatments.
NOTE:
The content of this article comes from a paper written by Chinese scientists.
Multimodal Locomotion and Cargo Transportation of Magnetically Actuated Quadruped Soft Microrobots
