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Title: Methods and microelectronics for proprioceptive neural feedback
Author: Williams, Ian
Awarding Body: Imperial College London
Current Institution: Imperial College London
Date of Award: 2014
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A neural implant giving an amputee a sense of feeling back in their prosthetic limb could help millions of people live happier, more productive lives. Tactile feedback is commonly targeted, however, it is the lesser known sense of proprioception that is crucial for smooth, coordinated limb control and non-visual limb awareness - both of which are high priorities for amputees. This thesis describes research carried out to progress the development and creation of aproprioceptive neural prosthesis targeted at trans-humeral upper limb amputees. Firstly a review of proprioceptive neural prosthesis design considerations and challenges is presented. The purpose of which is to identify areas requiring further development and to identify a prototype target system that focuses and scopes design effort. Then 3 technical chapters cover research into: (1) Combining efficient implementations of biomechanical and proprioceptor models in order to generate signals that mimic human muscular proprioceptive patterns. A neuromusculoskeletal model of the upper limb with 7 degrees of freedom and 17 muscles is presented and generates real time estimates of muscle spindle and Golgi Tendon Organ neural firing patterns. (2) An 8 channel energy-efficient neural stimulator for generating charge-balanced asymmetric pulses. Power consumption is reduced by implementing a fully-integrated DC-DC converter that uses a reconfigurable switched capacitor topology to provide 4 output voltages for Dynamic Voltage Scaling (DVS). A novel charge balancing method is implemented which has a low level of accuracy on a single pulse and a much higher accuracy over a series of pulses. The method used is robust to process and component variation and does not require any initial or ongoing calibration. (3) A non-invasive proprioceptive feedback trial platform (using vibration induced proprioception) for testing modelled neural signals. A low cost vibration device is designed and tested, identifying key issues with this form of non-invasive feedback.
Supervisor: Constandinou, Timothy Sponsor: Engineering and Physical Sciences Research Council
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral