Finite Element Analysis of a Novel Lower Extremity Exoskeleton with a Polycentric Knee Joint

This paper presents the mechanical design and finite element analysis of a revolutionary “lowEr eXtremity eXoskeleton with a pOlycentric kNee (EXXON)”, which is developed with the objective of providing assistance to paralysed people to accomplish their daily tasks, improve their quality of life and facilitate a quicker and more effective lower limb rehabilitation process to patients. Ergonomic design principles are adhered in order to make EXXON comfortable and simple for users to operate. At first alloy steel 4340, Ti-6Al-4V, Al alloy 7075-T6 and Al alloy 6061 were picked up and finally aluminium alloy 7075-T6 is selected as the material for EXXON due to its excellent characteristics. Structural and buckling analyses are performed through finite element modelling in ANSYS on a single limb of EXXON to check whether it can sustain the loads acting on it for different weight of users. As the frame is loaded, the interpretation of the stress distribution is established. The numerical results are further validated with the analytical ones.