| Popis: |
Long term exposure to microgravity environment in spaceflight causes some health issues such as space motion sickness, shift in body fluids, muscle atrophy and bone demineralization. Studies have shown that aerobics, and resistive exercise could help astronauts to deal with the issues. Rowing exercise can provide both resistive and aerobic exercise. A rowing exercise machine has mechanical parameters which affect the user’s movement and the loads on the user’s tissues. If these effects can be predicted, exercise results can be improved. However, human testing is only possible on Earth during the development, and also the absence of gravity may affect the task execution in the space. Therefore, computational modeling is necessary. In this thesis, a computational model of an arm based on human musculoskeletal simulation and optimal control was used to investigate the effects of mechanical properties of the exercise machine on predicted human performance. Moreover, the other goal was to study the effects of the exercise on arm motion and tissue loads during the exercise. To explore this concept, we have modeled a scaled down rowing exercise machine and a biceps mus- cle. A system identification has been done on the Concept2 rowing machine to determine baseline machine parameters. In order to solve the problem, different methods in trajectory optimization were evaluated to choose the reliable one. Then, a linear muscle force generator was coupled to the rowing machine to examine how it performs the task. The design parameters were changed to investigate their effects on the movement. Finally, the simple muscle force generator was replaced by a brachii muscle model to study how it executes the exercise. Effects of the design elements were also studied. |
