Full citation
Yin, X. H. 2025. "Flexible capacitive sensor arrays for human interaction and smart manufacturing". M.A.Sc. Thesis University of British Columbia, Vancouver, Canada.
Abstract
This thesis presents the design, fabrication, characterization and initial application of soft capacitive sensor systems, with applications in human–computer interaction and composite manufacturing.Yin, X Two distinct platforms are developed: a 36 element, three-axis gesture-recognition sensor array; and a capacitive Smart Roller for automated fiber placement (AFP). Together, they illustrate the potential of integrating soft materials, flexible electronics, and data-driven methods into practical sensing technologies.
Touch gestures are a form of human interaction that includes emotional information. Gestures involve shear, but, until now, this component has not been recorded. In order to do so, a 6 × 6 three-axis (normal force and shear) capacitive sensor array was adapted for detection of light touch typical of tickling, patting and other interactive gestures. It consists of a polyimide flexible printed circuit board, a low durometer, pyramidal patterned silicone dielectric layer, and stretchable conductive fabric electrodes. A dataset of over 7,578 gesture instances was collected from 16 participants, capturing nine gesture types. Deep learning models were implemented to classify gestures, with results showing that inclusion of shear information improved accuracy to 83%, compared to 79% with normal stress data alone. These findings confirm the expressive contribution of shear sensing to the recognition of social touch.
In composite manufacturing, local pressure in important for setting the bonding between layers of carbon fibres, while path planning on complex lay-up surfaces could be critical to reliability. To investigate the effects of normal force, two cylindrical sensor arrays were Smart Roller prototypes were fabricated and evaluated. The first, a 4 × 13 taxel array, demonstrated sensitivity to surface irregularities of 0.2 mm. The second, a 10 × 1 array, improved lateral spatial
iv
resolution, enabling detection of 0.16 mm gaps and laps. Gap regions detected by the sensor were validated through peel tests, which confirmed their detrimental effect on adhesion. These results highlight the Smart Roller’s potential for in-process quality monitoring in AFP.
Overall, this work establishes a complete pipeline for capacitive sensing systems. The findings provide a framework for advancing soft sensor technologies across diverse applications where compliance, sensitivity, and adaptability are required.
Touch gestures are a form of human interaction that includes emotional information. Gestures involve shear, but, until now, this component has not been recorded. In order to do so, a 6 × 6 three-axis (normal force and shear) capacitive sensor array was adapted for detection of light touch typical of tickling, patting and other interactive gestures. It consists of a polyimide flexible printed circuit board, a low durometer, pyramidal patterned silicone dielectric layer, and stretchable conductive fabric electrodes. A dataset of over 7,578 gesture instances was collected from 16 participants, capturing nine gesture types. Deep learning models were implemented to classify gestures, with results showing that inclusion of shear information improved accuracy to 83%, compared to 79% with normal stress data alone. These findings confirm the expressive contribution of shear sensing to the recognition of social touch.
In composite manufacturing, local pressure in important for setting the bonding between layers of carbon fibres, while path planning on complex lay-up surfaces could be critical to reliability. To investigate the effects of normal force, two cylindrical sensor arrays were Smart Roller prototypes were fabricated and evaluated. The first, a 4 × 13 taxel array, demonstrated sensitivity to surface irregularities of 0.2 mm. The second, a 10 × 1 array, improved lateral spatial
iv
resolution, enabling detection of 0.16 mm gaps and laps. Gap regions detected by the sensor were validated through peel tests, which confirmed their detrimental effect on adhesion. These results highlight the Smart Roller’s potential for in-process quality monitoring in AFP.
Overall, this work establishes a complete pipeline for capacitive sensing systems. The findings provide a framework for advancing soft sensor technologies across diverse applications where compliance, sensitivity, and adaptability are required.
Year Published
2025