Abstract
Currently, manned space exploration is being promoted actively internationally. In this context, an optimal walking motion control technique in microgravity environment is required. More precisely, it is necessary to clarify the kinematic changes of locomotion under microgravity. On an anti-gravity treadmill using pneumatic pressure, subjects can walk quickly with a relatively light load and a weight bearing condition up to 20% of body weight. Thus, it is considered to be a useful method to compensate for the drawbacks of conventional partial weight bearing methods. However, during walking on the anti-gravity treadmill, ground reaction forces and joint angles cannot be measured by a large force plate and an optical measurement system. Therefore, during this research, a walking simulation in a microgravity environment was realized by using an anti-gravity treadmill, and the walking motion was measured with a wearable motion measurement device. The conditions of the anti-gravity treadmill were set to five conditions of weight rates of 100 %, 80 %, 60 %, 40 % and 20 %. The evolution of ground reaction forces and joint angles during one gait cycle were calculated from each sensor's output, and the influence of partial weight bearing on the gait was examined by comparing the calculated values. As a result, from the changes observed in ground reactions forces and joint angles, it was found out that the gait becomes floating and gets closer to a slow tiptoe walking style as the weight rate is small with the anti-gravity treadmill. Furthermore, from the changes in joint angles, it was found out that the walking behavior characteristics of the lower body greatly change between the weight rate of 40% and 60%.
