SPEAR is an Active Ankle-Foot Orthosis (AFO), aimed at providing an affordable solution for rehabilitating foot drop of stroke survivors.
Stroke patients often suffer from foot drop, a gait abnormality usually due to the paralysis of the anterior portion muscles of the lower leg, causing an inability or impaired ability to raise the foot at the ankle joint. This leads to extremities of the foot being dragged along the ground while walking, causing tripping and other accidents. Braces or splints that fit into shoes are prescribed to help hold the foot in a normal position. For rehabilitation, most patients are trained to walk with canes, and therapists prescribe physiotherapy for a series of short, intensive sessions. These solutions are expensive and slow processes as they require the presence of skilled personnel and are carried out for short durations.
The AFO is designed to rehabilitate the foot by augmenting the human musculoskeletal system. It is actuated using McKibben Muscles (Pneumatic Artificial Muscles), which are driven pneumatically. They are cost-effective, lightweight and compliant, offering a significant advantage over Motor Driven orthoses. The orthosis is controlled using Electromyography(EMG) signals from the muscles involved in the motion of the ankle. The EMG sensors are non-invasive, and all computation and control required for the operation of the orthosis run onboard the orthosis in real time.