Advances in the Study of the Musculoskeletal Multi-rigid-body Dynamic Modeling in Manned Space Flight

With the advancement of China’s manned space program from near-Earth space to deep space exploration, the protection of astronauts against musculoskeletal injuries during long-duration space missions and their adaptation to low-gravity environments during extraterrestrial exploration have become critical issues concerning astronaut health and safety. To address the limitations of ground-based experiments in studying human motion and musculoskeletal system responses in microgravity/low-gravity environments, musculoskeletal system modeling and simulation technologies, based on biomechanical principles and computer-aided design, have emerged as novel methods and tools for evaluating astronaut exercise regimens and analyzing the kinematics and dynamics of microgravity/low-gravity environments. This paper introduces the principles of musculoskeletal system multi-rigid-body dynamics modeling in space environments, including forward dynamics-driven and inverse dynamics analysis methods. Taking OpenSim software as an instance, this paper elaborates on the procedure of constructing human-device-environment models in microgravity/low-gravity environments and the solution of muscle forces and joint torques via inverse kinematics and inverse dynamics algorithms. Furthermore, to assess the credibility of musculoskeletal modeling and simulation methods for manned spaceflight research, the relationship between experiments and modeling/simulation is analyzed. Based on existing literature, credibility assessment is conducted from eight factors: data pedigrees, input pedigrees, code verification, solution verification, conceptual validation, reference validation, results uncertainty, and results robustness. On this basis, the application of musculoskeletal system dynamics modeling and simulation methods in three key areas is reviewed as follows: assisting astronauts in space exercise by comparing the advantages and disadvantages of different exercise regimens and designing space station-compatible exercise equipment; optimizing extravehicular spacesuit design by calculating joint reaction torques through human-spacesuit coupling biomechanical models and improving spacesuit design to enhance comfort and work performance; and supporting extraterrestrial exploration by focusing on research into human motion characteristics in low-gravity environments and the development of human-spacesuit-exoskeleton systems to confirm the effectiveness of exoskeleton systems in planetary exploration. Finally, the limitations of musculoskeletal system multi-rigid-body modeling and simulation methods are analyzed, and new perspectives on future research directions and application prospects are proposed.