Kinematic Modeling of Balance Recovery Movements of a Standing Passenger following its Support Surface Translation

An experiment was designed to observe balance recovery movement of standing volunteers in public transportation situations, and attempt to predict it. A perturbation corresponding to a typical emergency breaking situation was applied to the platform on which the subjects were standing. The effect of three different postures, three acceleration profiles and two external constraints were studied. Movements were reconstructed using a three dimensional whole body kinematic model. The reconstructed kinematic data were reduced prior to the movement analysis. The simplified representation obtained showed that the balance recovery movement consists of a succession of four basic phases, and also allowed to highlight the influence of the experimental parameters. In order to evaluate whether the data generated can be used to predict the motion in arbitrary conditions, the response of the intermediate acceleration level tests was predicted by interpolation between the two extreme conditions. The prediction was successful using a simple interpolation method. This result, while encouraging, should be verified using different conditions. More experimental data should be collected for that purpose.