Design and development of a wearable inductive textile sensor to monitor back movements

This thesis focuses on the design and development of a wireless and wearable platform that employs an inductive sensor to track trunk movements when the user bends forward. The inductive textile sensor was designed based on the anthropometrical dimensions of the trunk's lumbar area of a healthy female. The chosen shape of the sensor was a rectangular flat coil. The inductance behavior was investigated using theoretical calculations and simulations. Formulas developed by Grover and Terman were used to calculate the inductance to validate the inductive textile design. The simulations were used to analyze the change of the inductance when the area, perimeter, height, and width of the rectangle was modified, as well as the effect of the number of turns of the rectangular flat coil. Results from the theoretical calculations and simulations were compared. The inductive textile sensor was integrated at the lumbar section of a sleeveless garment to create a smart wearable platform. The performance of the smart garment was evaluated experimentally on a healthy participant, and it was shown that the designed sensor can detect forward bending movements. The evaluation scenario was further extended to also include twisting and lateral bending of the trunk, and it was observed that the proposed design can successfully discriminate such movements from forward bending of the trunk. An interference test showed that, although moving a cellphone towards the unworn prototype affected the sensor readings, manipulating the cellphone when wearing the prototype, did not compromise the capability of the sensor to detect forward bends. The proposed platform is a promising step towards developing wearable systems to monitor back posture to prevent or treat low back pain associated with poor posture.