A compact motorized end-effector for ankle rehabilitation training.

Area of Science:

• Robotics
• Rehabilitation Engineering
• Biomechanics

Background:

• Ankle injuries are common and require effective rehabilitation.
• Existing rehabilitation methods may lack personalized support and patient engagement.
• Robotic systems offer potential for precise and adaptive therapeutic interventions.

Purpose of the Study:

• To introduce a novel compact end-effector ankle rehabilitation robot (CEARR).
• To develop a voluntary-triggered control (VTC) strategy using surface electromyography (sEMG) for adaptive rehabilitation.
• To assess the CEARR's ability to support ankle range of motion (ROM) based on user intent.

Main Methods:

• Designed a bilaterally symmetrical robot with three degrees of freedom (DOF) per side.
• Integrated actuators and foldable brackets for patient comfort and varied postures.
• Implemented a real-time VTC strategy using root mean square (RMS) of sEMG to control robot velocity support.
• Collected sEMG and torque data from healthy subjects during voluntary ankle movements.

Main Results:

• The CEARR system successfully accommodates dorsiflexion/plantarflexion, inversion/eversion, and adduction/abduction movements.
• The VTC strategy demonstrated consistency between voluntary movement and robot support ( R² ≈ 0.67 on nonlinear sEMG).
• Triggering velocity trends showed high consistency with linear torque signals ( R² ≈ 0.99).

Conclusions:

• The CEARR system provides a promising platform for ankle rehabilitation.
• The sEMG-based VTC strategy enables adaptive and personalized robotic assistance.
• The robot's design and control strategy support comprehensive ankle ROM rehabilitation.