Design of Wearable Soft Robotic System for Muscle Stimulation Applied in Lower Limbs during Lunar Colonization

The Moon has always represented a bewitching world for humanity. However, it also represents a hazardous environment for colonization. The first stages for these purposes will necessarily require the biomedical support to reduce the consequences of space conditions on the astronauts. Therefore, this study has been conducted from 2019 to 2020 under the supervision and guidance of Space Medicine and Biomechatronics Research Group-TMSP; resulting in the proposed project labelled as "Medical Robot". This paper presents the design of a wearable soft robotic system to stimulate, rehabilitate and reduce the harmful effects of space conditions in the muscles involved during the astronauts' gait in future lunar missions. This system uses elastomeric pneumatic actuators, capable of exerting mechanical stimuli on astronaut's muscles and improving the blood flow in the lower limbs, reducing the adverse effects of long inactivity periods in hypogravity, as muscle atrophy. In addition, it generates a solely one direction free displacement when pressurized, becoming highly efficient. Thus, the final system has 7 soft pneumatic actuators which were arranged and embedded in 3 silicone matrix to be placed at specific anatomical points of the lower limbs. Furthermore, at 50kPa of inlet air pressure, the actuator demonstrates a maximum free displacement of 6 mm. Finally, this conceptual design was made using the software "Autodesk Inventor 2020"for the 3D design and "Ansys Workbench 18.1"for mechanical simulation. In conclusion, favourable results were achieved; therefore, the next version of this project will be its implementation and development using multiple silicone materials to make the device wearable, comfortable, safe, easy handle, and easy-to-sterilize; which is expected to be ready by 2021.