Skin based Pressure/Tactile Sensor

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dc.contributor.advisor Aw, KC en Yellapantula, K en 2019-06-11T01:51:01Z en 2019 en
dc.identifier.uri en
dc.description Full Text is available to authenticated members of The University of Auckland only. en
dc.description.abstract Tactile sensing systems have received increasing attention due to the promise shown towards imitating human skin. The main challenges in achieving skin-like tactile sensing exist in current designs, fabrication processes and sensing systems. This research proposes and successfully develops a new tactile sensor focusing on object identification and pressure sensing. A scalable and repeatable fabrication process was established to realise a piezoresistive pillar-based skin sensor that is sensitive to compressive pressures. Sensors containing 3 × 3 array of piezoresistive pillars with pillar heights of 1 mm, 2 mm and 4 mm were fabricated. The pillars were made from a Carbon Black (CB) filled Ecoflex™ composite while the electrodes were made of a CB, PDMS and Ecoflex™ composite. The active elements were encompassed within Ecoflex™ to produce a flexible sensor. An Automated Characterisation System was developed to characterise the sensors. The sensor with a pillar height of 4 mm was deemed most suitable and enabled sensing through a simple circuit. Resistance spikes were observed with changes in applied pressure. A linear increase in resistance with applied pressure was observed under loading for pressures up to 135.4 kPa with a sensitivity of 0.919 Ω/Pa. During the unloading cycle, a non-linear relationship was observed resulting in a hysteresis of 42.4%. A need for preconditioning was identified to produce repeatable results. Resistance relaxation was observed with constant pressures. The resistance relaxation behaviour and high hysteresis deemed the sensor unsuitable for purely static loading applications. A cross-talk compensated sensing system was developed using an Arduino Mega which scanned the sensor achieving a refresh rate of 438 Hz. A calibration scheme was devised to derive internal models for each sensing pillar thus accounting for the variability among pillars in the sensor. The acquired data was processed through a Python script to produce 3D pressure maps in real-time. The tactile sensing system was successful in providing tactile information of various objects in the form of a 3D pressure map. Overall, the pillar design, fabrication process and sensing system enabled a pressure sensitive skin sensor that is capable of identifying the shapes of objects. en
dc.publisher ResearchSpace@Auckland en
dc.relation.ispartof Masters Thesis - University of Auckland en
dc.relation.isreferencedby UoA99265158614002091 en
dc.rights Items in ResearchSpace are protected by copyright, with all rights reserved, unless otherwise indicated. Previously published items are made available in accordance with the copyright policy of the publisher. en
dc.rights Restricted Item. Full Text is available to authenticated members of The University of Auckland only. en
dc.rights.uri en
dc.rights.uri en
dc.title Skin based Pressure/Tactile Sensor en
dc.type Thesis en Engineering en The University of Auckland en Masters en
dc.rights.holder Copyright: The author en
pubs.elements-id 774372 en
pubs.record-created-at-source-date 2019-06-11 en

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