Dynamic Modeling and Analysis of Astronauts' Exercise during Spaceflight

Astronauts' exercise during spaceflight will bring low-frequency disturbance to the spacecraft. In order to analyze the corresponding dynamic effects on the spacecraft, an astronaut-cycle ergometer-spacecraft system is taken as an example. The dynamic model is established in this paper. The topological structure of the astronaut-cycle ergometer-spacecraft system is given and equalized to an open tree system. Utilizing recursive relation of displacement and velocity between connected units, equations of motion of the system are reduced to the spacecraft. Simulation implies astronauts' exercise will result in rotational drift of the spacecraft. Meanwhile, the microgravity environment is heavily destroyed. Compare with traditional modeling method, our method is more accurate as it considers dynamic coupling effects. The simulation results can be considered as a reference to the control system and it also reveal changes of microgravity environment.