Application of Goertzel Algorithm to Piezoresistive Pressure Sensing Fabric for Custom Fitting of Wheelchair Cushions

2020 ◽  
Vol 1 (2) ◽  
Author(s):  
Justin Trzeciak ◽  
James A. Mynderse
Keyword(s):  
Low Cost ◽  
Sine Wave ◽  
Pressure Sores ◽  
Interface Pressure ◽  
Pressure Sensing ◽  
Wheelchair Users ◽  
Common Location ◽  
Goertzel Algorithm ◽  
Ischial Tuberosities ◽  
Seating Surface

Abstract Pressure sores are a costly, painful problem for wheelchair users, caused by prolonged periods of mechanical loading. A common location of pressure sores in wheelchair users is the tissue between the ischial tuberosities and the seating surface. The pressure exerted on the tissue, or interface pressure, can be measured using piezoresistive fabric. This work demonstrates the use of the Goertzel algorithm for efficiently acquiring interface pressure data from a fabric assembly consisting of a layer of piezoresistive fabric between two layers of fabric with conducting and non-conducting stripes. The Goertzel algorithm was used to sample sums of sine waves from the conductive columns of the fabric assembly and calculate the amplitudes of each component sine wave corresponding to the local interface pressure. The Goertzel algorithm is more efficient for this application than a fast Fourier transform due to the limited number of calculated frequency bins needed for this application and more freedom in choice of sample size. The algorithm was successfully used to generate two-dimensional, 32 × 32 sensel interface pressure maps once per second. The Goertzel algorithm can be used in tandem with generated sine waves to measure interface pressure from piezoresistive fabric. Low-cost, accurate interface pressure measurements will help lessen the risk of pressure sores in wheelchair users.

scholarly journals A comparative sudy of two pressure relieving techniques on three different wheelchair cushions

2006 ◽  
Vol 62 (2) ◽  
Author(s):  
C. Eksteen ◽  
P. Cilliers ◽  
A. Swanepoel ◽  
E. Vermaak ◽  
Q Trollip ◽  
...  
Keyword(s):  
Null Hypothesis ◽  
Friedman Test ◽  
Interface Pressure ◽  
Pressure Monitor ◽  
Pressure Relief ◽  
Wheelchair Users ◽  
Sample Group ◽  
Matrix Cell ◽  
Ischial Tuberosities ◽  
Experimental Study Design

Introduction: Pressure relief done by a spinal cordinjured patient is of utmost importance in order to prevent pressuresore formation. Some pressure-relieving techniques are describedin previous literature, but their effectivity has not yet been deter-mined on different wheelchair cushions.Null Hypothesis (H0): The null hypothesis (H0) stated for thistudy is that there is no difference in the effectivity of forwardleaning and forward leaning towards the left as pressure relievingtechniques for quadriplegic wheelchair users over the differenwheelchair cushions.Design: An analytical experimental study design using a convenient sample group of ten complete lesion quadriplegics (C6 to T1) was performed at the Physiotherapy Department,University of Pretoria.Method: Interface pressure (in mmHg) over the ischial tuberosities and upper thigh areas was measured using theTalley Oxford Pressure Monitor MKII with a 12-way matrix cell system.Results and Conclusion: The Friedman test for associated observations indicated statistically that the leaning  diagonally forward pressure relieving technique is more effective for all three wheelchair cushions used in this study.

Ultrasensitive, flexible, and low-cost nanoporous piezoresistive composites for tactile pressure sensing

Nanoscale ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 2779-2786 ◽  
Author(s):  
Jing Li ◽  
Santiago Orrego ◽  
Junjie Pan ◽  
Peisheng He ◽  
Sung Hoon Kang
Keyword(s):  
Carbon Nanotube ◽  
Polymer Composites ◽  
Low Cost ◽  
Pressure Sensors ◽  
Nanoporous Carbon ◽  
Pressure Sensing ◽  
Etching Method ◽  
Piezoresistive Pressure Sensors

We report a facile sacrificial casting–etching method to synthesize nanoporous carbon nanotube/polymer composites for ultra-sensitive and low-cost piezoresistive pressure sensors.

A low-cost, portable system for the assessment of the postural response of wheelchair users to perturbations

1999 ◽  
Vol 7 (4) ◽  
pp. 435-442 ◽  
Author(s):  
D.G. Kamper ◽  
T.C. Adams ◽  
S.I. Reger ◽  
M. Parnianpour ◽  
K. Barin ◽  
...  
Keyword(s):  
Low Cost ◽  
Postural Response ◽  
Wheelchair Users ◽  
Portable System

Effects on interface pressure and tissue oxygenation under ischial tuberosities during the application of an alternating cushion

2015 ◽  
Vol 24 (3) ◽  
pp. 91-101 ◽  
Author(s):  
Sandra Arias ◽  
Eladio Cardiel ◽  
Laura Garay ◽  
Hiromi Sanada ◽  
Taketoshi Mori ◽  
...  
Keyword(s):  
Tissue Oxygenation ◽  
Interface Pressure ◽  
Ischial Tuberosities

scholarly journals Evaluation of cushions using dynamic pressure measurement

1991 ◽  
Vol 15 (3) ◽  
pp. 232-240 ◽  
Author(s):  
C. A. Bar
Keyword(s):  
Dynamic Pressure ◽  
Pressure Sores ◽  
Patient Assessment ◽  
Pressure Monitoring ◽  
Time Profiles ◽  
Pressure Time ◽  
Subject Variability ◽  
Dynamic Pressure Measurement ◽  
Ischial Tuberosities ◽  
Spinal Cord Injured

Reduction of pressures generated in the tissues overlying the ischial tuberosities is an important measure for predicting a cushion's effectiveness. In particular, the pressure-time relationship is significant in the prevention of pressure sores. In this study a dynamic pressure monitoring system was used to obtain pressure-time profiles for 25 spinal cord injured subjects. Each subject tested three types of cushion (Foam, Gel (Aberdeen) and Roho) for periods of two hours each during which routine activities were performed. Results obtained were broadly comparable with previous studies. Average pressures were: Foam 87.6mmHg (11.6kPa); Gel 68.6mmHg (9kPa) and Roho 54.6mmHg (6.7kPa). Pressure-time histograms are presented for three subjects for each cushion. These show inter-subject variability on the same cushion as well as intra-subject variability on different cushions. Therefore individual patient assessment is important in providing the most appropriate cushion. Dynamic pressure monitoring allows the pattern of pressure variation to be determined and hence the potential effectiveness of the cushion.

Preventing pressure sores in wheelchair users

1994 ◽  
Vol 8 (20) ◽  
pp. 54-56 ◽  
Author(s):  
Lesley Stockton
Keyword(s):  
Pressure Sores ◽  
Wheelchair Users

scholarly journals Design and validation of a low cost, high-capacity weighing device for wheelchair users and bariatrics

2016 ◽  
Vol 29 (2) ◽  
pp. 61-67 ◽  
Author(s):  
Brandon A. Sherrod ◽  
Dustin A. Dew ◽  
Rebecca Rogers ◽  
James H. Rimmer ◽  
Alan W. Eberhardt
Keyword(s):  
Low Cost ◽  
High Capacity ◽  
Wheelchair Users
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