C-JAE: 3 DOF Robotic Ankle Exoskeleton with Compatible Joint Axes

This paper proposes a three degrees of freedom (DOF) robotic ankle exoskeleton with compatible joint axes, named C-JAE. The device consists of three separate units to achieve triplanar motions. The plantarflexion-dorsiflexion and inversion-eversion are externally powered, whereas internal-external rotation is passively supported. C-JAE is capable of complying with the functional and ergonomic requirements of the biological ankle joint. This is achieved by accurately mapping exoskeleton axes of rotation with the oblique axes of rotation of talocrural and subtalar joints of ankle. All mechanisms including the drive units are located anterior to shank and foot segments to carry out robotic rehabilitation and/or to provide locomotion assistance for humans having mobility disorders. Control experiments were conducted to assess aptitude of C-JAE to carry out ankle rehabilitation exercises. The results verified potential benefits of the proposed design to generate desired movement patterns of daily activities while providing power-assistance.