A numerical simulation of the mechanical structure of an ankle exoskeleton oriented to elderly people

This paper presents the numerical simulation of a 3D mechanical design of an ankle exoskeleton for elderly users. The ankle is one of the most injury-prone joints due to its irregular ¾ sphere shape and elderly people are more prone to this damage (approximately 80% of patients with a history of ankle sprain undergo surgery for post-traumatic ankle osteoarthritis [1]). This problem generates a decrease in muscular resistance on the legs, loss of motor skills, loss of mobile autonomy, etc. The simulation of this exoskeleton is intended to reduce these problems by means of this low-cost mechanism, since similar options exist, but they are not within the economic reach of all. For this reason, anatomical measurements of an elderly user were taken to obtain an ergonomic and easy-to-use mechanical design. Biomechanical calculations were also performed on the ankle to define its displacement and rotation angles. Finally, the designed parts were assembled to validate the mobility of the system and numerical simulations were performed to determine safety coefficients, Von Misses stress, and deformations within the Autodesk Inventor 3D CAD software.