Assessing the discomfort of the whole-body multi-axis vibration: laboratory and field experiments.

Laboratory and field experiments were conducted to determine the best procedure for predicting the discomfort caused by multi-axis vibration. In the laboratory experiment, 11 seated subjects compared single-axis vibration in one axis to single-axis vibration in another axis, and compared dual-axis vibration to single-axis vibration. In the field experiment, 22 lorry drivers rated the discomfort of 16 different rides. The results show that the best procedure for predicting the discomfort is to combine the vibration inputs by taking the square root of the sum of squares of the weighted r.m.s. values of the vibration in each axis.