Decrements in Tracking and Visual Performance during Vibration

Abstract

This literature review specifies the decrements in human performance on tracking and visual acuity tusks during vibration in terms of frequency, acceleration, and direction of vibration. For z-axis (vertical) vibration, which has been studied most extensively, it has been possible to develop tentative equal-decrement curves in terms of frequency and acceleration. For x-axis (longitudinal) and y-axis (lateral) vibration, there are not enough data to do SO. The effects of other variables are discussed briefly, and an hypothesis is offered for translating experimental results into predictions of performance decrements for workers in vibration environments. INTRODUCTIONWhen people are subjected to vibration, their ability to perform tasks is often substantially impaired. In addition to causing discomfort (and sometimes sickness), vibration interferes with the ability to see clearly, as when reading instruments or written materials, and the ability to control one's bodily movements precisely, as when steering or writing. Such degradation of human performance leads to inefficient and even hazardous operation of air, sea, and land vehicles in which vibration inevitably occurs.The principal aim of this literature review is to determine how direction, frequency, and acceleration (or amplitude) of vibration affects tracking and visual performance. Ideally, a vehicle designer would like to determine, in advance, how large the decrement in performance on various tasks will be for a person operating a vehicle with certain frequency and acceleration characteristics. In this review the intention is to extract, from the literature, estimates of performance decrements in representative tasks across a broad range of frequencies and accelerations. With this kind of information, the design of new vehicles and improvement of existing vehicles can be directed toward minimizing the types of motion most detrimental to task performance.This review is divided into three major sections: (1) the effects of vibration on tracking tasks; (2) the vibration effects on visual acuity (Data from various sources are plotted on acceleration vs. frequency graphs and lines of equal decrement in performance are drawn where possible); and (3) recommendations for future experimental research.The measure of vibration most commonly used in the literature is the zero-to-peak value of sinusoid acceleration. However, the rootmean-square value is typically used as a measure of random vibration. To make graphs easily comparable, rms accelerations have been converted to "equivalent" zero-to-peak values by multiplying all rms levels by fi Grether (1971) has written a comprehensive review of the literature on vibration and human performance. This paper ~ extends Grether ' s conclusions in several significant ways. First, the figures in this paper make it possible to compare percentage decrements across various studies in the tracking and visual performance literature. Second, the important problem of translating results from sinusoidal vibration studies into predic...

A numerical study of vibration-induced instrument reading capability degradation in helicopter pilots

“…Similarly, Ishitake [10] reported a maximum reduction of visual acuity at a frequency of 12.5 Hz. Collins [11] noticed the significant contribution of human biodynamics on visual performance degradation above 10 Hz, which compares favorably with the above-mentioned findings. In [12], 12 Hz is also indicated as the target frequency for the effect of vibration on visual acuity in a combined positive G manoeuvre and sustained vibration .…”

The repetition timing of high frequency afferent stimulation drives the bidirectional plasticity at central synapses in the rat medial vestibular nuclei

“…The vestibular system shows various adaptive and compensatory phenomena like visuo-vestibular calibration (Lisberger and Miles, 1980;Miles and Lisberger, 1981;du Lac et al, 1995;Broussard and Kassardjian, 2004), vestibular compensation (Curthoys and Halmagyi, 1995;Cameron and Dutia, 1997;Beraneck et al, 2003), vestibular habituation (Collins, 1973;Jeannerod et al, 1976;Cle´ment et al, 1981Cle´ment et al, , 2002Courjon et al, 1985) and homeostatic processes (Sadeghi et al, 2010). The mechanisms underlying these plasticity phenomena are not completely clarified as yet, but many evidences suggest that synaptic longterm potentiation (LTP) and long-term depression (LTD), as well as neuronal excitability changes, taking place within the medial vestibular nucleus (MVN) might be the neural basis for ocular motor learning (Lisberger, 1988;du Lac et al, 1995;Cameron and Dutia, 1997;Raymond and Lisberger, 1998;Beraneck et al, 2003;Pettorossi et al, 2003;Gittis and du Lac, 2006).…”

Ergonomics of Field Machines

“…Compensatory tracking eye movements, which protect visual acuity for low frequency vibration below about 1 to 2 Hz, b. Amplification or attenuation of vibration from the seat to the head, and c. Resonances within the eye at high frequency which above 20 Hz [2] Visual performance was affected by vibration frequencies range 10 to 25 Hz [3]. By comparing vibration of observer only and vibration of display only, vibration would affect observer while frequency is over 10 Hz; and vibration would affect acuity while display frequency is below 10 Hz [4].…”