A soft-bodied millirobot developed by researchers at the City University of Hong Kong (City U) could one day guide medical imaging devices and drug delivery inside your body.
The robot, inspired by animals such as ants, cheetahs and starfish, is capable of leaping over obstacles 10 times higher than its leg length, carrying objects more than 100 times its weight and moving at “ultrafast” speeds of more than 40 leg-lengths per second.
The key to its super abilities lies in its multi-legged design. Despite being only 17 mm long, the robot has hundreds of tiny, hair-like legs — measuring 0.65 mm — which, combined with their tapered feet, help significantly reduce friction between the robot and the ground.
This frees the robot to move easily and efficiently over dry surfaces as well as through wet and uneven environments such as the human stomach.
The legs also serve to support the body — and its cargo. By distancing the legs approximately 0.6 mm apart, Assistant Professor in City U’s Department of Biomedical Engineering Dr Shen Yajing, who led the study, along with his team, was able to counteract the weakness of its soft legs. The leg length to gap ratio (1:1) seen in the robot mimics that found in soft-bodied animals such as starfish, centipedes and pillworms.
The robot’s mobility can also be attributed to its silicon-based polydimethylsiloxane body.
In a City U press release, Professor Wang Zuankai, who initiated the project, explained that: “both the materials and the multi-leg design greatly improve the robot’s hydrophobic property. And the rubbery piece is soft and can be cut easily to form robots of various shapes and sizes for different applications”.
Better still, the robot can be controlled remotely by applying an electromagnetic field to iron particles embedded in its legs and body. With the help of a magnet, the researchers were able to make the robot walk forward, flap, climb and swing sideways.
According to Yajing, “The amazingly strong carrying capability, efficient locomotion and excellent obstacle-crossing ability make the milli-robot extremely suitable for applications in a harsh environment, such as delivering a drug to a designated spot through the digestive system, or carrying out a medical inspection”.
In two to three years, Yajing and his team hope to create a biodegradable robot that will naturally decompose after delivering its load. In the meantime, they intend to test new shapes and add extra features before one day testing it on animals and humans.
