Shi, Ge;
(2023)
Fingertip-inspired mechanical-based haptic feedback system.
Doctoral thesis (Ph.D), UCL (University College London).
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Abstract
Upper limb amputations pose significant challenges for amputees, especially in developing countries where access to affordable prosthetics is limited. Various prosthetics, including passive, body-powered, myoelectric, hybrid, and exoskele- ton, offer unique features and capabilities. Recent advancements in 3D-printing have made low-cost upper limb prosthetics more accessible. However, despite restoring some hand motion, current prosthetics lack haptic feedback, an essential component for a complete sensory experience in daily life. This thesis presents a fluidic mechano-tactile haptic feedback system for upper- limb amputees that transmits tactile stimuli from a fingertip sensor and produces corresponding mechano-tactile stimuli. The system is mechanically driven with only two components: a fingertip sensor and a feedback actuator. Incompressible liquid fills the cavity, acting as a medium to transfer pressure signals from the fingertip sensor to the feedback actuator. The feedback actuator then generates corresponding mechano-tactile stimuli for the user, indicating the force level at the fingertip sensor. The effectiveness of this fluidic mechano-tactile haptic feedback system has been proven. The haptic feedback system was optimised using a multi-chamber structure to sense and provide feedback on force level and direction. Both the fingertip sensor and feedback actuator have a multi-chamber structure and are connected individ- ually. By compressing the fingertip at different angles and indentation depths, the pressures in the chambers increase non-uniformly, resulting in pressure amplitudesthat deviate and indicate force level and direction. The prototype has been characterised and validated with healthy participants. To analyse the deformation of the fingertip sensor, an analytical model based on finite deformation theory was developed, describing the inflation and compression of an ellipsoid. By establishing the hyperelastic property and membrane dimensions (including thickness, major and minor axis lengths), the reaction force, hydrostatic pressure, and deformed shape of the membrane can be calculated. The model was validated through experiments. Following finite deformation theory, another ana- lytical model was developed to describe the inflation of a circular elastic membrane under load. This model was validated with three experiments, contributing to the fields of soft robotics and haptic feedback.
| Type: | Thesis (Doctoral) |
|---|---|
| Qualification: | Ph.D |
| Title: | Fingertip-inspired mechanical-based haptic feedback system |
| Open access status: | An open access version is available from UCL Discovery |
| Language: | English |
| Additional information: | Copyright © The Author 2023. Original content in this thesis is licensed under the terms of the Creative Commons Attribution-NonCommercial 4.0 International (CC BY-NC 4.0) Licence (https://creativecommons.org/licenses/by-nc/4.0/). Any third-party copyright material present remains the property of its respective owner(s) and is licensed under its existing terms. Access may initially be restricted at the author’s request. |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science > Dept of Mechanical Engineering |
| URI: | https://discovery-pp.ucl.ac.uk/id/eprint/10183155 |
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