Mechanical Analysis of a Hybrid Approach for a Lower Limb Rehabilitation Robot

The design of lower limb rehabilitation robot can be categorized into two approaches: the end-effector and the exoskeleton. Both types of the robots have different advantages and disadvantages. The exoskeleton type is designed to mimic the kinematic structure of the human skeleton by controlling hip and knee joints but the end-effector type is driven at the footplate which allows patients to perform various gait training exercise. In this paper, the end-effector and exoskeleton device are compared based on dynamical analysis using Matlab's Simechanics simulation. The hybrid lower limb rehabilitation robot is also proposed based on the exoskeleton robot with the adjustable mechanical coupling interface between human and robot and the active footplate. The hybrid design combines the advantages of both the exoskeleton and the end-effector by allowing the mechanical coupling parameters and the active footplate controller to be adjustable at different stages of training. The proposed design can improve both joints misalignment and joint trajectory tracking problems in both existing approaches.