Interference in writing performance under whole-body vibration exposure together with subject posture

摘要

Train passengers often experience difficulty in performing various sedentary activities such as writing during travel. This study identifies the influence of three primary parameters viz., vibration level, vibration direction and sitting posture on writing performance for an improved activity comfort in trains. Therefore, an experimental study was conducted on a mock up of rail vehicle to examine the interference in writing task under random vibrations excited in mono, dual and multi axis in low frequency range of 1-20 Hz at 0.4, 0.8 and 1.2 m/s~2 amplitudes. Thirty healthy male subjects were assigned the task to write the given characters in two seated postures (on lap and table posture). The performance was evaluated subjectively using Borg's CR-10 scale and quantifying the distortion in writing. The results revealed that the degradation in writing performance was found to increase with vibration stimuli and reported maximum in both lateral and vertical direction equally. Similarly, the effects of multi axis vibration were found similar to dual axes vibration and greater than mono axes vibration. While higher degradation in performance was found while working on lap than on table in X-direction, however, all other mono and multi axis vibration reported maximum in table posture.