SCSC2003 Abstract S21711
Simulating the Effects of Ship Motion on Postural Stability Using Articulated Dynamic Models
Simulating the Effects of Ship Motion on Postural Stability Using Articulated Dynamic Models
Submitting Author: Prof. Robert Langlois
Abstract:
Ship motions have the undesirable effect of making it more difficult for humans to move in a controlled and coherent manner while onboard ships, thus causing routine tasks to be impaired, hazardous, or in severe cases impossible to perform. A means of measuring such impairments is through the measurement of Motion Induced Interruptions (MIIs). These are defined as occasions when a person would have to stop working at their current shipboard task and either take a step or hold onto some convenient anchorage to prevent loss of balance. MIIs occur if the person in question tends to slip on the deck or topple over as the result of ship motion. Currently the probability of MII occurrence is most often computed using a model based on the dynamics of a rigid block resting on the ship deck. This model correlates reasonably with experimental data though it tends to overestimate the number of MII occurrences because of the rigid body assumption. In practice, a person may change their
stance, crouch, or sit down if they anticipate an imminent MII. This paper presents the development of two articulated postural stability models that include joint articulation at the ankles in a medial plane model and joint articulation at the ankles and hips in a frontal plane model. Details of the model and controller development as well as validation data and sample results are presented.
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