The Gait Orthosis. A Robotic System for Functional Compensation and Biomechanical Evaluation

Abstract

Knee ankle foot orthoses are prescribed to provide stability and maintain lower limb joints at their functional position. Current devices provide stability by locking joints permanently during the unsafe phase of a pathological gait (the stance phase). Though stability is obtained with such orthoses, gait patterns are unnatural and non-cosmetic. Other systems adapt more dynamically during gait, applying different strategies to recover or improve mobility. The system presented consist in a wearable set of sensors, actuators at knee and ankle joints, and a control and monitoring ambulatory unit, all integrated in a custom designed knee-ankle-foot robotic exoskeleton. A base unit allows wireless communication of the ambulatory unit, trough a Bluetooth link, with a PC software platform conceived for on-line and off-line data evaluation. Sensors adapted to the mechanical frame of the orthosis collect kinematics, such as angles at knee and ankle joints, and angular positions and accelerations at lower limb segments; kinetics, such as forces at the orthosis rods and fixation parts, and also foot contact information.