Development of an actuation system for a rotary hydraulic brake on a low cost light weight knee-ankle-foot orthosis

In the field of rehabilitation following a stroke (Cerebral Apoplexy), having the patient walking as soon as possible is critical to recovery. Current practices rely heavily on the manual assistance of nursing staff to achieve this. To assist during this phase a low cost light weight single strut knee-ankle-foot orthosis (KAFO) has been developed. However the orthosis requires walking with the dysfunctional leg in a fixed straight stance resulting in the walking gait being difficult and unnatural. To achieve near natural gait walking a light weight hydraulically actuated rotary brake has been prototyped for this orthosis. This paper outlines a prototype actuation control system for this hydraulic brake during a walking gait. The controller uses a microcontroller provided with gyroscopic, angle, velocity and acceleration data and uses an algorithm to combine the data and actuate the rotary brake. The proposed controlled KAFO is low cost, light weight, low power and easy to setup.