Engineers from MIT and Shanghai Jiaotong University have developed a prosthetic hand that can precisely inflate each finger to grasp objects, while providing haptic feedback to the user.
MIT states that more than five million upper arm amputations are performed around the world each year, and although many amputations may have to do with static prostheses, recent advances in articulating the prosthesis “robotic” prosthetics and sensory feedback have made the devices marketable. take the remaining muscle signals and convert them into hand movements. But such technology can be heavy and expensive.
The soft prosthetic limb by the team of engineers at MIT and Shanghai Jiaotong University is said to weigh about half a pound (~225 g) and have a total component cost of around $500 – making it reasonably likely. as well as easier to use.
The fingers in the new system are made from a commercially available soft and stretchy elastomer called EcoFlex with bone-like fibers embedded within. They are attached to a 3D printed stand shaped like a human palm.
Instead of attaching motors to control each finger module, the MIT setup uses a small pump and valve at the user’s waist (to keep the weight of the prosthetic limb down) for precise inflation. fingers to form specific shapes. And this pneumatic system is controlled via EMG sensors attached to the user’s limbs.
Using computer modeling, the researchers designed a controller to inflate fingers into something similar to five common gripping actions – including pinching, fisting and palm stroking. hand.
An algorithm that converts muscle signals into gripping patterns is then used to program the controller for common tasks, such as holding a wine glass, where the mechanical signals are picked up by the sensor. will be converted by the controller to the right pressure and each finger is then inflated by the pump to create the required grasping shape.
The team also incorporated a pressure sensor for each fingertip, then connected them all to specific regions of the user’s remaining limb to provide real-time haptic feedback.
Two volunteers were trained to contract the muscles in their arms while visualizing five common grips in their minds, then tasked with performing tests of hand strength and dexterity, such as checking, writing with a pen, picking up fragile objects, and lifting heavy balls. These tests were repeated using a commercially available prosthesis, with volunteers reporting that the MIT system was “as good, or even better, at most tasks, compared to its rigid system.”
The researchers also note that one of the volunteers demonstrated the device’s effectiveness in everyday use – being able to grip things like hammers and pliers, use soft prostheses to ingest food like cakes and apples, and even shake someone’s hand. Blindfolded, volunteers were also able to identify which fingers were touched by the researchers and said they could register bottles of different sizes when placed in their hands.
A patent has been filed for the design and work continues to improve sensing capabilities and range of motion before commercialization is possible.
“This is not yet a product, but the performance is already comparable to or superior to existing neuroesthetic substances, which we are very excited about,” said MIT professor Xuanhe Zhao. “There is huge potential to make this soft prosthesis at a very low cost, for low-income families with amputations.”
An article on the development was published in the journal Natural Biomedical Engineering. The video below shows the prosthesis in use.
Inflatable robotic hand gives amputees real-time tactile control