Swiss sensory motor scientists are hoping to inspire a new generation of more flexible, less constraining, powered exoskeletons that improve the lives of the severely disabled and paralysed.Metal exoskeleton suits worn outside the body, delivering energy for limb movement, are becoming more widespread, helping survivors of strokes, spinal cord injuries, and other lower extremity weaknesses to walk again.Yet they are far from perfect solutions. A patient’s joints can be misaligned with those of the exoskeleton, thus constraining the wearer’s walking. They are also usually bulky, making climbing stairs impossible, while the limitations of their joint mechanisms makes anything other than walking in a straight line difficult, slow, and inefficient, and in some cases unachievable.ETH Zurich (Swiss Federal institute of Technology) researcher Volker Bartenbach told Reuters that a prototype developed at the institute’s Sensory Motor Laboratory allows users far more freedom.”Hopefully we will build systems that allow you to do more tasks,” he said. “Besides walking in a straight line, you might be able to walk sideways in front of your kitchen counter or something like that, to walk stairs up and down. Also to turn round on the spot, so they need different joints, they need different degrees of freedom and if we had a system that was powerful enough to support you but also less constraining to allow you those movements you would be able to do such movements, even if you were a paraplegic or handicapped person.”
Bartenbach and professor of sensory motor systems, Robert Riener, are seeking to replicate the natural kinematics of human lower limbs, in an attempt to improve the type of exoskeleton currently being manufactured.Pointing to one of the exoskeleton hip joints, Bartenbach demonstrated to Reuters how the device could allow users to move their joint in a variety of ways. “We have here the hip joint, so if I move my leg like this the exoskeleton provides this degree of freedom. The same, different degree of freedom is, for example, the adduction abduction, so if I spread my leg to the side and this is also provided here by the exoskeleton, by the joint, so if I’m inside I can still perform this movement,” he said.He added: “The human also has internal, external rotation, so we can rotate our hip around this axis, which we need for example if you turn around on the spot – and here you see we are testing a technical solution, how to reproduce it, how to allow this movement. What you can see here is this four bar linkage mechanism. If you have multiple joints connected in a certain way then we allow the leg inside to still perform this movement.”
source:Reuters
