Design of a Passive Robotic ExoSuit for Carrying Heavy Loads

Abstract

In this paper, a soft upper-extremity passive robotic exosuit is presented. This exosuit intends to assist workers when they are carrying heavy loads. The feature of the proposed exosuit design is that it consists of a light plastic frame and a cable system mounted via joints on the frame. Polyethylene braid-style cables are used which have a high strength of extension up to 34kg and low deformability. Comparing to the rigid frame exoskeleton, the mass and the inertia of the cable are negligible. With the help of cable winding and locking mechanism, during the transporting phase of load carrying, the gravity of the load can be compensated by cables and redistributed on the shoulder and thigh. Hence the pressure of muscles on arm can be relieved. In order to have the optimal assistive effect, the positions of anchors and cable attachment points have been optimized. An experiment has been conducted with a preliminary prototype mounted on a mannequin test bench. Experiment result shows that with the help of this exosuit, the mannequin test bench can steadily hold its posture when a 10kg load is applied and meanwhile, its joint mobility is not affected when it is in the non-carrying-load mode.