Electronic Thesis and Dissertation Repository

Thesis Format

Monograph

Degree

Master of Engineering Science

Program

Mechanical and Materials Engineering

Supervisor

Naish, Michael D.

Abstract

Haptics can enable a direct communication pipeline between the artificial limb and the brain; adding haptic sensory feedback for prosthesis wearers is believed to improve operation without drawing too much of the user's attention. Through neuroplasticity, the brain can become more cognizant of the information delivered through the skin and may eventually interpret it as inherently as other natural senses. In this thesis, a wearable haptic feedback device (WHFD) is developed to communicate prosthesis sensory information. A 14-week, 6-stage, between subjects study was created to investigate the learning trajectory as participants were stimulated with haptic patterns conveying joint proprioception. 37 healthy participants were divided into three groups, with each group assigned a different haptic stimulation method (τ0, τ1 or τ2). 18 participants managed to complete the study within 7{14 sessions, demonstrating that participants were, in fact, learning to interpret the haptic information. Participants in group τ2 had some advantages in interpreting the haptic information over the others; however, each stimulation method has advantages that can be exploited and hybridized for future models of the WHFD. Learning rates within groups were highly variable and deterred significantly with increasing quantities of simultaneous information. A secondary investigation determined strategies to improve the ability of the haptic actuators to transfer information to the user, which will be employed for future prototypes. Overall, the proposed WHFD is an effective device that can promote greater sensory awareness for wearers of prostheses.

Summary for Lay Audience

Amputees may regain some functionality with the assistance of an artificial limb, but many affordable prosthetic limbs do not restore the ability to sense. Everyday tasks such as grasping and reaching are difficult due to the missing senses of touch, temperature, and joint motion. Lacking these senses can often lead amputees to abandon their prosthesis altogether. This thesis presents a prototype of a wearable vibration device, that can present the sensory information from a bionic limb as vibrations on the skin. Similar to how a blind person can learn to read using their fingertips, an amputee can experience the senses captured from their prosthetic limb as they learn to interpret the vibration patterns. Three vibration patterns were created and tested to determine the best one to help people learn the meaning (hand and wrist gestures) behind the vibrations. Despite interruptions due to COVID-19, a multi-week experiment found that, no matter what vibration pattern participants were given, they were able to understand the vibrations as hand motions to a satisfactory level of accuracy. One vibration pattern was found to make it easier for participants to interpret the vibrations compared to the other two patterns.

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