Introduction

This project describes the design and development of the technology for a textile-based posture monitoring system by using a sensor matrix combined with accelerometers. 

The proposed system references the pressure distribution resulting from a human back when leaning against a soft backrest, on which a network of pressure sensors and accelerometers are placed. 

Therefore, the sensor system can evaluate the local curvature of the lumbar spine arch, allowing a clinician to advice on the posture. Posture feedback data from this system can benefit people who are suffering progressive degeneration of the spine disc.

 

Design and manufacturing

The sensor matrix is composed of five layers (from top to bottom):

1. one cover layer

2. sandwich-like pressure sensors: silver knitted fabric (grey strips) acting as electrodes and one piece of nonwoven piezoresistive fabric in the middle. And there are totally 35 sensors (yellow squares).

3. another cover layer attached with accelerometers (embroideried)

 

For pressure sensors, five postures were studied. While a yellow sensor means that it is not pressed or its resistance is higher than the threshold and a red one means it is pressed.

The following figures indicate the pressure distribution in different seated posture types:

(1). bending forward (2). leaning left (3). upright (4). leaning right (5). leaning backward

 

For accelerometers, three postures were studied.

1. Curve shape when seated upright

2. Curve shape when bending forward

3. Curve shape when leaning backward

 

Further works

1.Focus on the construction of a real-time system, by creating a data acquisition platform such as a mobile phone app.

2.The number of accelerometer should be increased, which will provide a more precise profile about the human back.

3.The data from sensor matrix and three accelerometers was collected separately, future research is necessary in order to provide a fully functional posture monitoring system.