• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.22 no.6
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• pp.535-541
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• 2012

The three-down one-up method which is commonly used in the field of psychophysics is employed in this study that is to reveal how much magnitude of vibration makes discomfort in passenger vehicle on idle condition. Thirteen taxi drivers were invited for subject of the experiment where they evaluated the controlled vibrations on rigid seat in terms of idle vibration on passenger vehicle at frequency range from 15 Hz to 40 Hz. As the result, vibration of 100~105 dB is marginal range to make discomfort on passenger seat. Frequency dependency of the discomfort was found at the frequency range, which is the higher frequency the lower discomfort with the same magnitude of vibration. The frequency dependency found here was compared with ISO 2631-1 that is more sensitive at the frequency range.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2011.10a
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• pp.535-539
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• 2011

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.11a
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• pp.1048-1052
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• 2003

This study aims to derive frequency weighting curves for the estimation of driver's discomfort by steering wheel vibration in the vertical and rotational direction with respect to a steering column. Subjective tests for the determination of equal sensation curves, inverse of frequency weighting curves, for the two kinds of vibrations were performed using the sinusoidal signals with reference amplitudes from 0.2m/s$^2$ to 0.4 m/s$^2$ in the frequency range from 5㎐ to 100㎐. Twelve subjects joined at the tests, and median values of the twelve judgments were used to determine the frequency weighting curves. Second experiment was followed to determine relative magnitude between the two frequency weighting curves by direct comparison of discomfort due to the two kinds of vibrations at 50㎐, which showed discomfort by the rotational vibration was 1.5 times of that by the vertical vibration.

• Transactions of the Korean Society of Automotive Engineers
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• v.18 no.1
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• pp.105-111
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• 2010

In the field of 'Human Vibration', it has been interested subjects to make equal sensation curves related to translational and rotational direction of whole-body, hand-transmitted and head-transmitted vibration, etc. When we consider the vibration of a vehicle, the main factor is vertical whole-body vibration. Until now, most of equal sensation curves used to derive frequency weighting function had been made using Western people. However, because of the inherent differences (for example, characteristic and shape of body parts, muscular and cellular tissue) between the Western people and the Oriental people, equal sensation curves based on Oriental people might be required. Also, the weight differences between the samples which consist of average-weighted and over-weighted group might cause the difference of equal sensation curves. So, in this study, 20 male Korean people were used to find equal sensation curves subject to vertical whole-body vibration on seated posture. Among 20 males, an over weighted group consisted of 10 male persons and an average weighted group was the others. Integrating and analyzing the data of two groups, some of non-parametric tests such as 'The Wilcoxon Signed Rank Test' and 'The Mann Whitney U test' were used.