Design and Fabrication of an Instrumented Handrim to Measure the Kinetic and Kinematic Information by the Hand of User for 3D Analysis of Manual Wheelchair Propulsion Dynamics

Abstract

The repetitious nature of propelling a wheelchair has been associated with the high incidence of injury among manual wheelchair users (MWUs), mainly in the shoulder, elbow and wrist. Recent literature has found a link between handrim biomechanics and risk of injury to the upper extremity. The valid measurement of three-dimensional net joint forces and torques, however, can lead to a better understanding of the mechanisms of injury, the development of prevention techniques, and the reduction of serious injuries to the joints. In this project, an instrumented wheel system was developed to measure the applied loads dynamically by the hand of the user and the angular position of the wheelchair user's hand on the handrim during the propulsion phase. The system is composed of an experimental six-axis load cell, and a wireless eight channel data logger mounted on a wheel hub. The angular position of the wheel is measured by an absolute magnetic encoder. The angular position of the wheelchair user's hand on the handrim during the propulsion phase (ɸ) or point of force application (PFA) is calculated by means of a new-experimental method using 36 pairs of infrared emitter/receiver diodes mounted around the handrim. In this regard, the observed data extracted from an inexperienced able-bodied subject pushed a wheelchair with the instrumented handrim are presented to show the output behavior of the instrumented handrim. The recorded forces and torques were in agreement with previously reported magnitudes. However, this paper can provide readers with some technical insights into possible solutions for measuring the manual wheelchair propulsion biomechanical data.

A 2D lightweight instrumented wheel for assessing wheelchair functionality/activity

“…In some cases, off-the-shelf 3D force transducers have been used, 11 , 15 while others have applied strain gauges directly to solid metal spokes connecting the push-rim to the wheel hubs. 10 , 13 , 16 More recently, Miyazaki and colleagues used four 2D load cells between a sports push-rim and a disc-shaped adapter plate to allow the measurement unit to be mounted to different sports wheelchair wheels as desired. 17 …”

“…To support this effort, wheelchair wheels have been instrumented with force sensors. [10][11][12][13][14][15][16][17][18][19] Most notably, the SMART Wheel12 and, later, the Optipush 18 systems have provided 3D kinetic data in many studies over the last 20 years, but since these are no longer commercially available, access to knowledge on the functional loading conditions in the upper extremities during dynamic activities has been limited to research developments.…”

“…In some cases, off-the-shelf 3D force transducers have been used, 11,15 while others have applied strain gauges directly to solid metal spokes connecting the push-rim to the wheel hubs. 10,13,16 More recently, Miyazaki and colleagues used four 2D load cells between a sports push-rim and a disc-shaped adapter plate to allow the measurement unit to be mounted to different sports wheelchair wheels as desired. 17 A highly stiff connection across the gap between the push-rim and the wheel hub is a common requirement in these different approaches, resulting in substantial bulk and weight in the range of 2.8 kg for the measurement unit 17 to a total of 5 to 6 kg.…”