Researchers at MIT (Massachusetts Institute of Technology) have developed a robot that is nearly transparent, can function in water, and execute fine motor control. In a demonstration, a model robot can be seen navigating through water, grasping a goldfish gently, and then releasing it. In another demonstration, the robots kicked a ball through water.
These robots are made from hydrogels, a rubber-like, transparent, moldable material that is connected to hollow tubes that give them structure and enable them to execute tasks. Researchers pump water into the hydrogel robot to give them shapes appropriate to the task: stretched out or curled up, as needed. Much like jellyfish, they can take in water and squirt it out to propel themselves. Because the hydrogels are made primarily from water, they have the same visual and acoustic properties as water, and thus are virtually undetectable, making them of interest for intelligence operations.
Hydrogels, made from polymers and water, have been in development for a number of years to develop a highly durable and flexible material that can be bonded to harder materials such as glass, metal, and ceramic. The MIT team, led by researchers Xuanhe Zhao and Hyunwoo Yuk, designed several versions of these hydrogel robots, each of which executes a different kind of motion: a finlike structure that can flap, an articulated appendage that kicks like a leg, and a hand-shaped structure that can grasp and release by squeezing and relaxing. The team used 3-D printing and laser cutting techniques to create their robotic structures, including the hydrogels and structural parts, which they then attached to rubber-like tubes connected to pumps, which enabled their propulsion and other movements. Yuk and Zhao’s technique produces forceful reactions that enable a hydrogel robot to generate a few newtons of force in only one second.
Zhao and team are collaborating with medical researchers to use these robots in surgical operations, where they can act as more gentle, precise “hands” for the surgeon, manipulating tissues with an exactness beyond the capabilities of the human hand, and able to operate in places difficult for a surgeon to reach.