2019 Volume 141 Pages 39-46
Passenger fatigue has been reported as one of the causes of marine accidents. In our previous study, we found that the passengers’ standing postural motions, such as motions of the head and hip, can cause physical fatigue because of energy expenditures were increased by standing postural motions in a small marine craft. It was also reported that human standing postural motions are affected by visual stimuli. It is therefore necessary to analyze the standing postural motions when affected by visual stimuli to clarify the causes of passengers’ physical fatigue. The purpose of this study is to investigate the effects of wave direction difference projected by a ship handling simulator on human standing postural motion. Standing postural motion was evaluated by linear and angular accelerations, exercise load calculated by energy expenditure and the motion of the center of gravity (COG). Eight participants were asked to observe four types of wave images (1： image without waves, 2： 180 degrees wave direction, 3： 135 degrees wave direction, and 4： 90 degrees wave direction). The COG motions of the participants were observed in response to the wave directions projected by the simulator. We therefore found that a standing postural motion occurred as a visual response to the direction of wave projected by the simulator.