Novel Design of a Rotation Centre Auto-Matched Ankle Rehabilitation Exoskeleton with Decoupled Control Capacity
Abstract This paper presents a novel ankle rehabilitation exoskeleton for post-stroke patients, with its rotational centre automatically conforming with ankle complex once people wear it. This exoskeleton has 2 rotation DOFs and is able to provide 2 different rotation patterns by reconfiguring. In the combined-rotation pattern arrangement, the mechanism can generate all three kinds of rotations that the ankle complex is naturally capable of realising. Among these rotational motions, adduction/abduction rotation is coupled motion. This rotation can be further reduced, or eliminated, by minimizing the distance between the lower connection points of the actuated links and the human ankle complex, and vice versa. For the other rotation pattern, a 90-degree arrangement of the side link offers decoupled motion control of the mechanism. Numerical studies reveal that the required rehabilitation workspace for dynamical gait exercises can be achieved with high dexterity, without generating singularities. Further investigations indicate that this mechanism has great potential for rehabilitating post-stroke patients of a wide range of heights and weights.