Anthro-X: Anthropomorphic lower extremity exoskeleton robot for power assistance

Lower extremity exoskeleton (LEE) robots are wearable devices that combine human intelligence with machine power to help perform functions of the limbs as intended by the user. Recently, anthropomorphic LEE solutions have gained wide spread interest to remedy the interference issues encountered at the human-robot interface. In that context, this paper presents a multi-degrees of freedom modular power-assist LEE robot with compatible joint axes to enhance kinematic compliance. The proposed LEE, named Anthro-X, supports all three DoF at the hip joint using a novel articulated mechanism. The polycentric motion of the knee joint is also facilitated using a unique mechanism based on four-bar linkage system. In total, Anthro-X has five DoF per limb where sagittal plane motions of hip and knee joints are powered by external power supply and others are passively supported. The prototype of the proposed LEE robot was fitted on a male subject to verify the kinematic conformity of hip and knee joint mechanisms. Experiments were then conducted to evaluate the effects of providing power assistance using Anthro-X during squatting exercises. Results indicate that the proposed design can be readily adapted for wide range of applications requiring motion or power assistance owing to its modular and anthropomorphic architecture.