A 4-bar mechanism based for knee assist robotic exoskeleton using singular configuration

Abstract

Recent progress in wearable exoskeleton robotics results from various needs of an aging society. This would spawn a vulnerable workforce in industry sectors to the near future. Thus, for the application to the industrial field, this work proposes an assistive robotic exoskeleton attached to the calf and thigh of the human leg to totally support a worker's body weight in stand-to-sit with the various seated positions. For this, in this work, a four-bar mechanism based various combinations of passive and active actuators are investigated. Finally the proposed system is composed of one rotary actuator and linear spring based on a four-bar mechanism, considering the high power efficiency for the weight and the mechanical solution to the backdrivability problem of a geared drive. From the extensive simulations, the basic actuation mechanism of the proposed assistive device is confirmed. Then it is verified from experimental results that the robotic exoskeleton can be used to aid who weighs maximum 85 kg in the arbitrary seated position and is actuated with nearly zero current consumption in the walking.