The world of prosthetics is an expensive one. As we have reported before, providing affordable mechanical hands and legs for amputees is an ongoing concern for engineers in the medical industry. Luckily, new technological innovations such as 3D printing and advanced sensing have allowed for the creation of new prosthetics that look and feel closer to their human counterparts.
One recent advancement has come from the Italian Institute of Technology and the INAIL state workers’ compensation prosthetic center. The Hennes robotic hand is a simple mechanical design that is lighter and cheaper than modern prosthetics. The Hennes is a robotic hand in which all five mechanical fingers can be controlled via a single motor. As compared to other such myoelectric prosthetics that use sensors that react to electrical signals from the brain to the muscles, the use of a single motor makes it lightweight and more cost-effective. It also makes the robotic hand more adaptable to handle different-shaped objects.
“This can be considered low-cost because we reduce to the minimum the mechanical complexity to achieve, at the same time, a very effective grasp, and a very effective behavior of the prosthesis,” says team researcher Lorenzo De Michieli. “We maximized the effectiveness of the prosthetics and we minimized the mechanical complexity.” The current price point of the Hennes hand is around €10,000, or $12,000. This is 30% cheaper than current market prices for prosthetics.
The light design of the Hennes will help to overcome some resistance users have had to the myoelectric hands, which in the past they found very heavy and difficult to manage. Dozens of labs around the world are trying to improve the myoelectric prosthetic, focusing on touch sensitivity or nervous system interaction. The Hennes, according to the Italian research team, is focusing on feel and should have the same weight as a human hand.
Marco Zambelli shows his prosthetic hand during an interview with the Associated Press in Rome on May 10. An Italian government-funded research institute and prosthetic maker unveiled a new robotic hand that they say enables amputees to grip objects with more precision, and which sports a mechanical design that will significantly bring down the price of a myoelectric prosthetic hand. (AP Photo/Gregorio Borgia)
Marco Zambelli, who lost his hand as a teenager, has been using the Hennes hand for the last three years. He is able to drive and use a table knife with the prosthetic with ease. “I have gotten very good at it,” says Zameblli. “I think anyone who's not looking with an expert eye would find it difficult to spot that it’s an artificial hand.”
The Hennes still requires refinement, as it lacks the ability to control individual fingers. That said, it can conduct the majority of daily tasks based on full grip movement. Future developments will most likely introduce individualized finger dexterity.
Check the video below to see the full range of motion of the Hennes.