Attaching sub-links on linear actuators of wearable robots for payload increase

A wearable robot with linear actuators is required to maintain over the desired payload over whole range of knee joint angle even when the user is walking, sitting down/standing up while holding up weights. However, in knee-flexion posture, the lifting payload at the knee joint decreases drastically by the moment arm of linear actuators and the cosine of joint angle. In order to solve the problem of the payload decrease, the sub-links attaching on actuators and the sub-link with shank bending method are proposed. As the result, two methods are successfully proved to increase the payload by simulation.