Development of Virtually Interfaced Robotic Ankle and Balance Trainer (vi-RABT)

Abstract

The ankle joint plays a vital role in our simplest every day activities such as standing, walking, running, and maintaining stable posture. It is usually under the stress of the entire body weight, and accordingly it is highly subject to physical trauma. Ankle injuries are also caused by neurological impairments such as stroke, cerebral palsy or traumatic brain injury. More than 2 million people require ankle rehabilitation each year because of the ankle related injuries. Due to varied severities of patient injuries or impairments, a need exists for a rehabilitation device that offers assistive and resistive therapy mechanisms in different stages of rehabilitation. The virtually-interfaced robotic ankle and balance trainer (vi-RABT) is a two degrees of freedom rehabilitation device that provides assistive and resistive therapy to the patients in need. The hardware is composed a stationary platform that hosts two robotic ankle trainers in addition to surrounding safety rails and harness. The system is actuated by two strong electrical motors to provide assistive and resistive therapy in seated or standing posture. Force and displacement sensors were integrated for monitoring and diagnostic capabilities. The software includes a closed-loop control strategy in addition to the virtual reality interface that provides an exciting, immersive therapy experience for the patients. The experimental results to validate the accuracy of the static force measurement using human subjects are presented. The system has a promising potential to be effectively used in physical therapy of ankle strength and range of motion, balance and variety of mobility disorders.