Researchers from the Florida Atlantic University have developed a new type of soft bionic finger that can move like the ones on your hand. In order to come up with the most authentic-looking design, they downloaded a CAD model of the human digit and used a 3D printer to create squishy inner and outer molds. Inside, they placed two actuators made of shape memory alloys (SMA), which can “remember” and return to their original shapes even after they get bent or deformed, so long as they’re heated. The extensor actuator straightens up when heat is applied, while the flexor actuator curves — you can see an illustration of how they work in the image below the fold.
During the testing process, the team applied heat by passing electric currents through a conductor. However, that doesn’t mean that they have this all figured out already. According to team leader Erik Engeberg, assistant professor at FAU’s Department of Ocean and Mechanical Engineering, there are still “challenges with this technology such as the lengthy amount of time it takes for them to cool and return to their natural shape.” That’s why the team has decided that the technology will be used for underwater robots first, as the environment enables rapid cooling. It might not be coming to bionic limbs anytime soon, but you can read the team’s journal published on IOPScience.