Design of a Sit to Stand Motion Robotic Assistance Device

This paper presents the design and the control solution of a “sit – to – stand” motion assistance device developed for the purpose of functional rehabilitation of patients after stroke. The device consists of a motorized exoskeleton structure that mimics human lower limb skeleton. The connections between the external mechanical structure and the human lower limb are realized via passive mechanical linkages, allowing the compensation of misalignment between the user’s anatomical joints axes and the rigid mechanical axes of the structure. Two linear DC motors are fixed at the knee and ankle levels, providing passive motions / assistance to motion for these joints. The interactive torques between the mechanical structure and the human’s limbs are controlled using torque sensors. First experimental results are presented and discussed.