Conceptual Mechatronic Design of Ankle-foot Exoskeleton System for Assisted Rehabilitation of Pediatric Patients with Spastic Cerebral Palsy

For this design, average anthropometric data specified by the National Institute of Health (NIH) were used for an 11-year-old child. Regarding the elements and materials, two motors with a reduction ratio of 500:1 were used, along with a control module that includes a rotary encoder for angle configuration, two Bowden cables for motion transmission, and an ankle-foot orthosis with variable angle adjustment. The results obtained for the motor ratio were a torque of 11.60 N.m. A Von Mises stress analysis was conducted on the support components made of ABS, the AISI 304 stainless steel pulley, and the PETG casing. Maximum stresses of 0.52MPa, 34.34 MPa and 0.95MPa were recorded, respectively. Finally, the ankle-foot working angle obtained for palmar flexion movement was 30°, and 20° for dorsiflexion. As future work, the exoskeleton will be implemented in a patient with spastic cerebral palsy, validating its impact on physical rehabilitation through gait analysis.