Robo-shorts which could help the frail to walk again, or boost the performance of athletes and soldiers, have been invented by engineers.
Exosuits which aid movement have been available for several years to help with rehabilitation, but they were generally bulky and could not switch from one speed to another, making them impractical for everyday use.
Now researchers at Harvard University’s Wyss Institute for Biologically Inspired Engineering have developed a pair of shorts which allows the wearer to move as if they were more than a stone lighter.
And crucially wearers can switch from walking to running without losing any of the performance.
The exosuit was developed as part of the Warrior Web programme, founded by the US military’s research arm DARPA (Defense Advanced Research Projects Agency) to help soldiers patrol for lengthy periods in rugged and uphill terrain while wearing bulky equipment.
The device works through a series of electronically-activated pulleys and thigh wraps attached to a belt which help lift the legs at the hip joint, making each step slightly easier.
In treadmill tests, using the shorts reduced the energy needed for walking by 9.3 per cent and by running by four per cent.
The reductions are the equivalent of a person walking or running with between 12 lbs to 1.2 stone less weight. Soldiers on patrol sometimes must carry seven stone in equipment so the exosuit could, literally, lighten their load.
And it worked on different gradients meaning it could also be used by climbers to assist them travelling uphill, or help older people climb the stairs.
“We were excited to see that the device also performed well during uphill walking, at different running speeds and during overground testing outside, which showed the versatility of the system,” said Dr Conor Walsh, a Founder of the Harvard Biodesign Lab.
“While the metabolic reductions we found are modest, our study demonstrates that it is possible to have a portable wearable robot assist more than just a single activity, helping to pave the way for these systems to become ubiquitous in our lives.”
Boosting walking and running with a single device have proven tricky in the past because the two movements are mechanically different. However, both gaits have in common an extension of the hip joint, which starts around the time when the foot comes in contact with the ground and requires considerable forced to propel the body forward.
The shorts are controlled by an algorithm which can spot when a user moves from walking to running or vice-versa, and adjust the tension on the legs accordingly. Because the body’s centre of mass changes when running or walking sensors are able to detect when the wearer has speeded up or slowed down.
"”e took advantage of these biomechanical insights to develop our biologically inspired gait classification algorithm that can robustly and reliably detect a transition from one gait to the other by monitoring the acceleration of an individual's center of mass with sensors that are attached to the body,” said Dr Philippe Malcolm, Assistant Professor at University of Nebraska Omaha.
“Once a gait transition is detected, the exosuit automatically adjusts to assist the other gait.”
The team previously developed a multi-joint suit which moves both the hip and ankle during walking, and a medical version aimed at Improving gait rehabilitation for stroke survivors is now used in hospitals across Europe and the US.
Experts believe the shorts open the door to implants which can activate muscles without the need for an exosuit.
The research was published in the journal Science.