Tiny Robots Can Move Using Water Instead of Electricity


Photo by: ArTDi101 via Shutterstock


Robots without an engine or batteries may soon become a reality as researchers at the Seoul National University have developed models that only need water. The robotic models are called hygrobots, small robots that move via absorption and evaporation of water.

The hygrobots are based on certain seeds, such as Pelargonium carnosum, which can move into the ground. The seeds can absorb moisture in the air, causing the outer coating to stretch. The stretching of the outer coating makes the seed bend.

Inspired by this, the research team applied the movement principle to small objects made of nanofibers. The nanofibers act as the outer coating, with some that are absorbent and some that are not. To enable movement of the hygrobots, each model has been designed in a specific shape, so that only one end moves whenever it relaxes. The result makes the hygrobots move slowly towards a direction as it bends and relaxes over and over again.

The movement of hygrobots can be controlled using the natural humidity in the surroundings. The researchers used both the cycle of moist and dry air and the right mixture of nanofibers in a dry environment to manipulate the small objects. The research team videotaped several models of hygrobots, such as the type that moves like an inchworm and the other that mimics a slithering snake.

The researchers suggest that hygrobots may be used in certain applications, such as in military and in hospital setting. One of the hygrobots has been tested to carry and deliver drugs without using an artificial power source. The antibiotic-coated hygrobot crawled and sterilized an area of a culture plate filled with bacteria.