Researchers have developed a robotic appendage that looks and acts just like a regular human finger. Using a novel heating and cooling technique, it mimics the action of a human finger, and could lead to much more precise prosthetic hands in the future.
The research was conducted by a team of scientists at the BioRobotics Laboratory at Florida Atlantic University, who have previously developed a working robotic arm. In their new research, published in the journal Bioinspiration & Biomimetrics, the team described how they developed and tested their latest innovation.
The researchers used a 3D printer to make the inner and outer moulds of the bionic finger, which house the artificial flexor and extensor – the muscles we use to extend and retract our finger. Those artificial muscles were made using a shape memory alloy (SMA), designed to respond to heat.
In this case, heating the finger caused the extensor to straighten, while the flexor tensed when it was cooled. "Thus, alternately heating and cooling the flexor and extensor actuators caused the finger to flex and extend," the researchers wrote in their paper.
Above is a separate robotic arm developed by the team. FAU BioRobotics Lab.
The light weight, dexterity, and strength of the finger supposedly makes it more useful than other bionic fingers. One drawback, though, is that the cooling process can take quite a while in air, so the researchers envisage this technology being useful in one particular environment – under the sea.
"Because SMAs require a heating process and cooling process, there are challenges with this technology such as the lengthy amount of time it takes for them to cool and return to their natural shape, even with forced air convection," said lead author Erik Engeberg in a statement. "To overcome this challenge, we explored the idea of using this technology for underwater robotics, because it would naturally provide a rapidly cooling environment."
Once an object had been grasped, it would take about a second to release it while underwater. The researchers note, though, that their design could be “adapted for use as a prosthetic device.” Advancements in battery technology are suggested as one area that could make this a reality.
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