Multi-legged millirobot overcomes obstacles to deliver medicines

The soft-robot, which is equipped with hundreds of caterpillar-like legs to help it carry heavy loads and traverse obstacles, was developed by a team led by researchers at City University of Hong Kong (CityU). The multi-legged design is also said to reduce friction, enabling the robot to move around areas inside the body that are lined or filled with fluids.

To arrive at their design, the team studied the leg structures of hundreds of animals, including those with 2, 4, 8 or more legs, and focussed on the ratio between leg-length and the gap between the legs.

"Most animals have a leg-length-to-leg-gap ratio of 2:1 to 1:1. So we decided to create our robot using 1:1 proportion," said Dr Shen Yajing, Assistant Professor at CityU's Department of Biomedical Engineering (BME), who led the research.

The robot’s conical legs are 0.65mm long and the gap between the legs is approximately 0.6mm, making the leg-length-to-gap ratio around 1:1. Laboratory tests showed that the multi-legged millirobot has 40 times less friction than a limbless robot in wet and dry environments.