Prediction of Human Postural Response in Shipboard Environments

In order to measure the human response to ship motion, postural stability experiments were performed during an eight-day heavy-weather sea trial in the North Atlantic Ocean. Data were recorded for thirteen participants as they performed a cognitive task without using their hands to maintain balance. The collected data were used to determine what sensory inputs the human participants received from their environment, the control forces and torques their muscles produced to react to those inputs, and the final body motions that were used to maintain balance. These experimental data sets were used to tune the control system of a human postural stability model. Analysis of simulation results indicate that there was a consistent relationship between the accuracy of the model’s motions and the direction of greatest ship angular motions, regardless of which direction the subject was facing. This result is significant because it demonstrates that an inverted pendulum model can be used to represent human motion both in the anterior/posterior direction and the lateral direction.