Researchers at the Massachusetts Institute of Technology have invented a bionic ankle-foot device that closely emulates how a real ankle works in people and allows amputees to walk and climb stairs more easily and naturally than existing prosthetic devices.
Veteran amputees can walk again thanks to prosthetic limbs that are constantly being improved. But most advanced prosthetic limbs still cannot mimic the true biomechanics of the human body.
Amputees say existing artificial limbs tend to be uncomfortable and difficult to use. While these devices allow them to walk, the resulting gait is awkward and proper balance can be difficult to achieve during a stride.
A device called the BiOM T2 System could change all that.
It emulates the function of the biological ankle and calf muscle through a unique propulsion system that uses two microprocessors and six environmental sensors.
As a person makes a stride, these sensors make thousands of calculations per second to adjust the stiffness of the ankle joint. Upon heel strike, the device stiffens the joint to dampen the impact, and thrusts the leg forward to supply power to the rest of the stride.
The ability to generate power and propel the person forward makes the BiOM T2 System unique.
Other prosthetic limbs made of pads, springs and hydraulics tend to focus on absorbing impact. But the human ankle and calf muscles store and release power to complete normal walking patterns.
Because power generation is not part of most traditional walking aids, amputees have to expend more energy initiating a stride.
The BiOM system solves that by allowing the natural mechanism by which the artificial ankle, calf and leg provides power in all stages of a stride, thus minimizing effort.
Settings can be adjusted through a software called “Personal Bionic Tuning.”
According to a study from which the device was based, BiOM
“decreased metabolic cost by 8 per cent, increased trailing prosthetic leg mechanical work by 57 per cent and decreased the leading biological leg mechanical work by 10 per cent, on average.”
The brainchild of MIT professor and bionics pioneer Hugh Herr, the BiOM T2 is intuitive enough to use even on the first or second try as claimed by a group of amputees who trialed the bionic system.
“Often, within minutes, a patient is walking around, even running around,”
Herr, who is BiOM’s chief technology officer, said in a press release.
The device seems capable of being used in more complex ways than just walking, running and climbing.
Herr showcased during a TED presentation last month a BiOM-equipped dancer who performed the rumba on stage.
BiOM could prevent degenerative diseases such as osteoarthritis, which can be triggered by obesity, cases of which are rising in the Middle East. The bionic ankle-foot prosthetic
“could help by fitting elderly populations with leg prostheses equal in biomechanical agility and control to a young adult’s legs,”
Herr said in a press release.
“We find ourselves in a position where we can put 18-year-old calf muscles on patients independent of their age, mitigating the problem of joint osteoarthritis across all populations,”
Drawing from his own experience as an amputee, Herr and his biomechatronics research team at the MIT Media Lab wanted to combine design, technology and the knowledge of the human body in creating products that conquer disability.
They have been developing smart prostheses and bionic exoskeletons that emulate or even enhance natural body functions.
“As we march into this century, technology is going to get more intimate with our bodies,”
“The bionic design approach is grounded in biological science that seeks to fundamentally understand how our bodies and brains work, and translates that knowledge into technology that reflects those principles, leading to a world where technology, because it is so innately human, essentially vanishes.”