3D printing electronics towards flexible tactile sensors

Abstract

The research described in this thesis explores the field of 3D printing technologies in the fabrication of printed, flexible tactile sensors and explores new possibilities and opportunities in the fabrication. The research is aiming at new ways of applying 3D printing fabrication techniques to develop easily applicable sensing structures to flexible, wearable applications.

Exploration into sensing principles and sensor designs for the printed fabrication of these tactile sensors results in the main design drivers of piezoresistive sensing and capacitive sensing to act as sensing mechanism for the developed sensors.

Fabrication principles are selected according to design thinking methods, and select and evaluate the trace design, substrate selection and 3D printing technique used in defining a concept proposal.

The performed exploration and design selection result in the concept proposal of a 3D printed tactile sensor using a TPU-coated nylon fabric substrate and ink-dispensed sensing structure using a Voltera V-One 3D printer. The sensing element is embedded into the fabric using heat sealing. A scalable, adaptable sensing array is proposed to allow for embedded tactile imaging capabilities.
The developed tactile sensor is validated by analysing a characterisation of the sensor readouts. A validation setup using a loadcell and vertical load is used to allow for the plotting of the sensors’ characteristics and linearity.

Validation shows evidence of significant measurement repeatability, while showing less proof for precise accuracy and resolution. Additional work needs to improve physical durability of the traces and connections.

The research concludes in a foundation towards the use of the 3D printing technologies of ink jetting/-dispensing to develop embedded sensor to be used in a large variety of tactile sensing/imaging applications.