ISVR Technical Report SCIENTIFIC PUBLICATIONS BY THE ISVR

Although many rail travellers use portable computers while travelling, the train environment has not been influenced by the desire to operate computers. Some trains provide power points and tables for portable computers, but an optimal design also requires understanding of how typing is disturbed by train motion. There are numerous studies of typing in static conditions and many studies of the interference of activities by vibration, but there have been few studies of the effects of vibration on typing. In the few studies previously conducted, the differing methods of measuring performance make it difficult to compare results. An experimental study has been performed to understand the effects of vibration magnitude, vibration frequency and vibration direction on typing performance. With 12 seated subjects in each condition, the effects on typing performance of five vibration magnitudes (0.63, 0.80, 1.00, 1.25 and 1.6 ms r.m.s.) of 30-s periods of sinusoidal vibration at each of twelve frequencies (0.50, 1.00, 1.25, 1.60, 2.00, 2.50, 3.15, 4.00, 5.00, 6.30, 8.00, 10.00 Hz) were determined for each of the three translational axes (x-, y-, and z-axis) of whole-body vibration. Performance was evaluated by three measures: (a) the total number of data entries in 30 s, (b) the number of typing errors, and (c) a subjective estimate of typing difficulty. The results are presented in tabular and graphical form. Subjective estimates of typing difficulty varied with the magnitude, frequency, and direction of the vibration. Lateral vibration, especially in the range 1.6 to 6.3 Hz, created the greatest difficulty. Vertical vibration caused least difficulty. There were no statistically significant effects of vibration on typing speed or typing accuracy, probably because extra effort was used to counteract the vibration disturbance.