Design and development: Actuator of powered knee orthosis a prototype

Abstract

Recent technological advances has made knee orthosis to become a robotic device known as powered knee orthosis (PKO). This paper describes the design and development of PKO which have high torque and high back-drive-ability. Both criteria are the most important things in designing a PKO to avoid control issues. There are many existing design of PKO, especially the main part of the design which is knee actuator. Outrunner type of brushless DC motor (BLDCM) as an actuator was used to give an external power to the user during knee flexion or extension. This device capable of assisting knee movement but feels transparent during movement. Simple preliminary shank lifting experiment tested on one healthy subject, was conducted and observed. Thus the approached PKO can lift the subject's leg during actuator on with highly back drivable during actuator off.