Development of a Gait System in Hypogravity Simulation for Physiological Studies on Earth and in Space

Running and walking stimulate and maintain the functioning of the musculoskeletal and cardiopulmonary systems, which are responsible for body posture, movement, strength and coordination on Earth and during space missions. This study aimed to develop a low-cost Gait System in Hypogravity Simulation (GSHS) for the study of human physiology. The developed construction consists of 5 subsystems: structural, suspension, simulation, force and communication. The GSHS is formed of a body suspension structure with a treadmill, connected to a force platform, welded upright at one end, with the volunteer suspended by a vest and elastic cables, and positioned in parallel to the ground. The maximum permitted weight for the system is 100 kg, taking into consideration the load capacity of the materials and components. A 72 kg object was pressed against the treadmill to test the force platform, and a motor with two rods and articulated mechanical feet was fastened close to the treadmill, allowing the surface to be touched during the human gait simulation. The results demonstrated the GSHS was able to suspend the object, maintaining it pressed against the treadmill without load variations. The communication subsystem stored and transferred the force platform CPU data to the computer. The force platform presented a 2.84% error in measurement of the object weight (72 ± 2.84 kg). The gait simulation test demonstrated the force platform was able to perform the real-time collection of touch time for each foot and the gait ground reaction forces. The GSHS was able to maintain communication between the force platform and data receiving system.