LifeMOD and NASA: Modeling Neuromechanical Events of Locomotion at Varying Gravitational Levels
United States space program
The National Aeronautics and Space Administration (NASA) is an agency of the United States government, responsible for the nation's public space program. In addition to the space program, NASA is also responsible for long-term civilian and military aerospace research. Since February 2006, NASA's self-described mission statement is to "pioneer the future in space exploration, scientific discovery, and aeronautics research."
Understanding neuromuscular dynamics and kinematics is critical for NASA engineers as they develop astronaut training and safety procedures for missions requiring long-term exposure to low and zero-G environments. To achieve this, multiple sources of information about muscle interactions with the skeletal system and how the nervous system controls these functions must be fully integrated. The purpose of this study was to determine the feasibility of using a neuromechanical model of human locomotion to simulate gait at various speeds and gravitational levels.
The musculoskeletal system and the environment with which it interacted were created as a 3D model in LifeMOD. The model was completely parameterized to allow for easy manipulation of environmental conditions such as ground stiffness, surface grade, and gravitational level. The muscles were 'fired' using a pattern-generator concept developed in MATLAB [The MathWorks, Inc.], which acted as the 'brain' of the model. A co-simulation was performed, with LifeMOD solving the dynamics equations of the locomotion mechanics and MATLAB solving the equations of the neuroscillator control.
The study revealed the importance of coupling a neural control system model with a musculoskeletal system model in order to study human movement dynamics. This coupling becomes even more important when factors related to gravitational load and speed of locomotion are to be considered.