Design, modeling and control of a series elastic actuator for an assistive knee exoskeleton

This paper introduces the design, modeling and control of a novel inherently compliant actuator with the ability to manually reconfigure the level of stiffness (CompAct-ARS). CompAct-ARS is intended to be utilized in assistive devices for legs, which will aid users in different motion tasks such as walking, sit-to-stand movement and squatting and will demonstrate the benefits of passive compliance. The actuator modeling design and mechanics are introduced. Experimental and simulation data are used in order to determine the design specifications of the actuator for its use in a knee exoskeleton system. Finally an assistive control strategy is introduced that will allow the proposed system to provide motion assistance to the subject knee.