Design and simulation of a lower-limb power-assist exoskeleton for hip joint based on deep squat

For lower-limb power-assist exoskeleton, following the motion of human smoothly requires that the motion ranges of related joints are in coincident with the characteristics of human motion. The knee and hip joints bend at maximum angle when doing deep squat, which is a significant case for exoskeleton research. In this paper, we introduce a slider-crank mechanism to handle the problem of unachievable bending angle in deep squat for present hip joint exoskeleton. Theoretical calculations confirm the feasibility of this mechanism and sizes of the hip joint components are determined by the whole structure of the exoskeleton. Structure simulations are performed on Adams which show the validity of the design and parameters such as the stroke of the hydraulic cylinder are also given.