Flexible Array Cushion Based on Short-Cut Carbon Fiber Reinforced CNT/TPU Aerogel Sensor for Sitting-Posture...

The sitting-posture monitoring strategies based on visual capture or inertial measurement units cannot be widely adopted because of light occlusion, privacy concerns, and wearing discomfort. In this work, a flexible piezoresistive sensor array based on the short-cut carbon fiber-reinforced carbon nanotube (CNT)/thermoplastic polyurethane (TPU) aerogel sensor (SCT) for sitting posture recognition was proposed. The results show that the compressive modulus of SCT₃ can be increased to 0.623MPa compared with pure TPU aerogel (0.053MPa), showing a low density (0.159 g/cm³) as well as high porosity (90.1%) due to the enhancement and supporting effect of short-cut carbon fiber (SF) in the matrix. The pressure sensing range of SCT₃ reaches 382 kPa, and good sensitivity (3.01kPa^-1) as well as durability (3500 cycles) can meet the real-time monitoring requirements of high pressure on hips. Additionally, an anti-crosstalk 8 × 8 array acquisition circuit was proposed to adapt the flexible array cushion, and a simple convolutional neural network was used to recognize five sitting postures, including proper posture, kyphosis, leaning forward, left-leaning, and right-leaning. This work proposes a sitting posture recognition strategy in a piezoresistive sensor array, which provides a promising approach to monitor sitting postures for adolescents.