Measurement System Development and Assessment of Whole Body Vibration Transmission in Power Wheelchairs
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Date
2015-05
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The Ohio State University
Abstract
Prolonged exposure to vibration is known to be detrimental to human health, causing pain and discomfort along the neck and spine and worsening injuries in those regions. Persons who use power wheelchairs are particularly susceptible to these dangers, many of whom have preexisting spinal conditions and as such are required to spend extended periods in a seated position. Previous studies have evaluated the effects of vibration, shock, and motion on humans in motor vehicle, industrial equipment, and even manual wheelchair applications. Little is known, however, about the particular characteristics of personal, power mobility solutions and the effects they have on users. The purpose of this study is two-fold: 1) to develop an adaptable system to enable the simultaneous collection of acceleration data from multiple points of interest (POIs) on power wheelchairs, and 2) to assess the dynamic characteristics of the power wheelchair to determine the transmissibility of whole body vibration at these points of interest. The first goal was met with the development of a nodal sensor system using the Arduino micro controller platform. The measurement system consists of a nodal unit which integrates an accelerometer with an Arduino Uno, a SD data logger to collect and temporarily store the data, and a wireless XBee RF radio to optionally stream data to a base computer. The system provides a simple, modular solution for collecting motion data from multiple locations and can be utilized for future mobility studies. To model it's dynamic characteristics, an anthropometric test device was used while the chair traversed a standardized road course. Acceleration data was collected at the frame, seat pan, and back support to develop the model. The results showed that the characteristics of the power wheelchair were unique in that the back plate is a critical location particularly for mid-wheel drive power wheelchairs. Vibration magnitudes were amplified by at least 1.5% from the chassis frame to the the back plate and were dissipated by 34.7% from the chassis frame to the seat pan when using a 100kg wheelchair test device. While this provides some indication on the dynamic characteristics of power wheelchairs, future work will be conducted comparing multiple wheelchair models with human users.
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Keywords
wheelchair, vibration, whole body vibration, power wheelchair