Asad Ali, Fahad Ali, Fawad Mushtaq, Asadur Rehman, and Usman Maqbool
Exoskeletons have been around since long for power enhancements, gait training and assisting paraplegic patients. Most of the commercially available exoskeleton systems address the patients with motor-complete paraplegia, cover both legs and are expensive. Examples include BLEEX, LOPES and HAL.
We argue that a large population in need of this new technology dwell in the low-income countries in Asia and Africa. Moreover, a large of them are affected by acute Poliomyelitis (or infantile paralysis) resulting in paralysis of only one leg. There are at least over a million polio survivors throughout the world according to WHO estimates.
Medical practitioners use orthosis to cater such patients since long. An orthosis is a rigid system of metal braces and splints locking certain joints to improve stability. However, orthosis does not allow natural walking motion for these patients.
Powered exoskeletons provide this missing component but due to the absence of widespread government welfare and health coverage, traditional high-tech exoskeletons are beyond the reach of most patients. Our goal is to develop such devices according to the needs of the developing world, using the above-mentioned constraints as our design guideline. The device has to be lightweight and minimal intervening only at joints wherever necessary.
Our system uses cheaper materials, commonly used in the orthotic industry, uses off-the-shelf sensors and actuators, and covers one leg. The design is inspired by the hip-knee-ankle foot-orthosis (HKAFO). The hip joint is a 2-DoF joint allowing the flexion/extension and abduction/adduction of the thigh link. Low-cost electronic sensors are used to provide vital information about orthosis state while a power transmission system is provided to provide power at the joints, wherever necessary.
With these improvements, we believe that the efficiency of leg orthosis can be improved by providing, for example, automatic knee locking/unlocking during different phases of walking.