A Conceptual Underwater Soft Exoskeleton for Augmenting Human Breaststroke

The structure and metabolic mode of the human body make it difficult to carry out underwater activities for a long time. Thus it is of great significance to promote the application of assisting robots such as exoskeletons for human underwater movement assistance. This study proposes a soft exoskeleton for enhancing human underwater activities by providing auxiliary torque for hip adduction during the sweeping stage of breaststroke. We designed a soft structure actuated by the elastic elements, which ensures efficient assistance while reducing the exoskeleton's restriction on the free movement of the human body. To facilitate the calculation of the auxiliary torque generated by the equipment, we established a static model. Additionally, we simulated the muscle activation of the adductor magnus in the sweeping stage to verify the exoskeleton's assistive effect. Our results show that compared to the situation without exoskeleton assistance, the two peak muscle activation levels of the adductor magnus with assistance decreased by 33% and 58% during the sweeping and lifting stages, respectively, thus confirming the feasibility of our design.