Wearable smart haptic interfaces towards embodied assistive devices

Abstract

The advancement of smart materials and structures has made wearable technology more attainable and versatile. The exploration of these materials and structures is of importance in order to develop wearable technology further and find new applications. The World Health Organization (WHO) estimates that the prevalence of physical disabilities across the globe is 0.5%, some 32 million people based on a global population of 6.4 billion in 2004. This includes people requiring a prosthesis, orthosis or some form of rehabilitation service. The uses and development of mobility aids for those with a physical disability are rapidly increasing. Although success rates of these devices are high in small, targeted groups, many problems still exist in addressing the range of conditions and needs in the wider population. The research presented in this thesis focuses on exploring the characteristics of various smart materials and structures for potential use in addressing the problems which originate from the interface between hard assistive devices and soft tissue of the human body, with a particular interest in prosthetic limbs. We aim to develop innovative technologies through the use of smart materials and structures to address these issues, targeting two key potential applications: to increase comfort and fit; and to use the body-device interface as a communication channel.
Fit and comfort of the prosthetic socket is addressed by exploring the use of auxetic structures as a means to accommodate residual limb volume changes that amputees experience throughout the day. Tiled auxetic cylinders (TACs) were designed, fabricated and characterised. These TACs can be tuned through design and geometric parameters, and we demonstrate their ability to react to the environment, highlighting their potential to improve the fit of prosthetic sockets.
The diversity of mechanoreceptors which are distributed through the skin, in addition to the great surface area of the skin, makes it ideal for its potential use as a communication channel. We developed wearable tactile devices that can communicate with the skin to convey a range of information. These devices succeeded in conveying natural and pleasant tactile sensations that could enable non-intrusive notifications to the user. Furthermore, we developed a sensory feedback device for potential use with upper limb prostheses which could increase the sense of embodiment. This device contains simple computation, and we demonstrate its potential use in everyday tasks.
All the devices created are wearable and we explored how these devices could be incorporated into fabrics with the hope of making them comfortable and discreet without interfering with the environment. This thesis highlights the potential of smart materials and structures to address the issues identified at the body-device interface of medical assistive devices.

Date of Award	6 Dec 2022
Original language	English
Awarding Institution	University of Bristol
Supervisor	Jonathan M Rossiter (Supervisor)