Optimization of exoskeleton design for post-stroke ankle rehabilitation based on kinematic and structural model evaluation

Ankle rehabilitation is an important indicator of walking ability recovery because it is used as a marker of early recovery of mobility function in post-stroke patients. Robot-assisted ankle rehabilitation has been proven to be more optimal for restoring range of motion, balance, and gait proprioception in patients. This study aims to optimize the design of an ankle rehabilitation exoskeleton through structural simulation, biomechanical alignment, and efficiency based on several alternative actuator designs. Alternative exoskeleton designs are focused on the rehabilitation of dorsiflexion-plantar flexion and inversion-eversion movements. The analysis method for assessing the best exoskeleton design alternatives uses an engineering design methodology approach based on static and dynamic test parameters, namely kinematics and FEA. The results of the design engineering implementation show that the exoskeleton design with Concept B is more efficient based on several mechanical test parameters compared to Concept A. Simulation results show that Design B alternative is superior in all test parameters with a value of (4.22 versus 3.68) in the safety factor, a lower peak stress of (30.43 MPa versus 39.15 MPa), and produces energy efficiency with lower torque requirements. The mechanical stability of Concept B is characterized by using a more efficient actuator design with superior safety improvements for users. Based on the parameters and characteristics of the simulation test using design engineering, Design B is more feasible to be developed as a robotic mechanical system for the needs of post-stroke patient ankle rehabilitation.