Pilot Studies of Vibrations Induced in Perambulators When Moving on Different Surfaces

Gustaw Sierzputowski,Sławomir Jarząb,Maciej Janeczek,Marta Majewska-Pulsakowska,Radosław Wróbel,Veselin Mihaylov

doi:10.3390/app11167746

Abstract

The ergonomics of transport is a topic widely described in the literature. One of the fields of ergonomics that researchers are engaged in is vibrometry (both laser and accelerometry) of travel and its translation into NVH (Noise, Vibration and Harshness). However, so far, the influence of baby carriage movement on the generated vibrations has not been described in more detail. The topic seems to be particularly important considering occurrence of vibrations with significant amplitudes, whose frequency range can have a direct bearing on the resonance frequencies of the child’s internal organs. The article presents the results of research consisting in the measurement of vibrations to which an infant, lying in two different types of prams, may be exposed when being transported on different surfaces. The author’s measurement system, based on accelerometry, was used for the research. The obtained weighted RMS acceleration values not only exceeded human comfort level in all cases (according to ISO standard) but several times were in the range of the highest discomfort (>2 m/s2). Furthermore, the observed vibration frequency range (≈0 ÷ 32 Hz) coincided with the frequencies of free vibration of organs and parts of the child’s body.

Highlights

The most important element when selecting a baby carriage should be assurance of the child’s safety
The present paper aims to fill this gap and demonstrate that some newer prams have a potential for transmission of more vibration compared to older prams, especially due to the lower weight and compact sizes
The articles [7,27] present a thesis which states that the direction of technological development of child safety seats has in recent years focused primarily on protecting children’s lives in road collisions, pushing vibration isolation into the background

Summary

Introduction

The most important element when selecting a baby carriage should be assurance of the child’s safety. Griffin in his article [16] describes a method of describing and assessing the sensation of the human body to vibrations while moving a vehicle He points out that an important aspect is to take into account the individual sensitivity of various organs to different vibration magnitudes, frequencies, directions and duration of vibrations. The articles [7,27] present a thesis which states that the direction of technological development of child safety seats has in recent years focused primarily on protecting children’s lives in road collisions, pushing vibration isolation into the background. The main contribution of this paper in the current knowledge is to show the difference in vibration comfort between the “old type” perambulator and the modern one, foldable to compact size, equipped with a universal frame and enabling the attachment of a child car seat or a stroller-type seat (parameters that can convince many new parents to buy it). It should be noted that not all currently produced prams follow the mentioned modern trends, offering considerably better damping properties

Subject

Data Processing

Frequency Domain

Conclusions