Design and Fabrication of Soft Sensors for Wearable Electronics and Robotics Applications

Abstract

This research work deals with the design and fabrication of fast ultra-flexible sensing devices through state-of-the-art technologies like multi-head 3D fabrication techniques and Reverse Offset Printing. The devices like soft sensors (strain and humidity sensors) have been developed with successful target of enhancing the features like sensing capacity, detectionrange, detection limit, cyclic stability, hysteresis,data reproducibility and accuracy. These milestones were significantly attained through articulatedcutting-edge research of selection of active material and its relevant synthesis, device structureoptimization through simulation and working principle and implementation of device using compatiblefabrication system. Two strain sensing devices were fabricated based on the novel conductive materials,Gly-KCL and PEDOT: PSS/MWCNTS after a fully optimized sensor' design using FEA tool ofCOMSOL 5.4. The developed strain sensors outperformed not only in terrestrial robotic and humanmotion monitoring but also under aquatic environment due to its water-proof design structure. Moreover,an environmental sensor based on humidity sensing device has also been developed which has primefeatures of biocompatibility due to active layer of Polylactic-co-glycolic acid (PLGA), all printedfabrication approach, full range responsive sensors (0%- 100%), highly linear and a portable wi-fienabled interactive system for sensor's response readout. For the characterization of devices, custommade setups with precise electronic controllers have been developed. The developed sensors have beencompared with the commercial as well as reported devices in literature and their results showed themstrong candidates to commercially available sensors. In the end, a soft robot mimicking real frog hasbeen modelled and fabricated based on ultra-flexible 3D printable Shape Memory Polymer (SMP)composite filament and shape memory alloy (SMA). After careful mathematical modelling, simulationbased optimization, the developed robot was able to achieve under water synchronous swimming withacceptable thrust force and the adoptability to swim under different applied frequencies using aninteractive GUI of LabVIEW controlled custom-made setup. In other words, this research workeffectively presents the logical combination of multiple fields of study to fabricate soft sensors withfocus on wearable and robotics applications.