MorphSkin: Adaptive Sensorised Skin for Upper Limb Prosthetics

Prosthetics are a valuable tool to restore lost functionality and improve quality of life of those with Upper
Limb Differences (ULDs), such as amputations. However, over 50% of UL prosthetics are rejected [1],
commonly due to the lack of durability [1] and mechanical robustness, as well being uncomfortable [2].
Increased durability and robustness would increase the life span of a prosthetic UL, reducing upkeep
costs. Residual limb1 (RL) movement within the socket (causing interfacial pressures) and RL volume
changes [3] can negatively affect comfort. Design improvements to increase durability and mechanical
robustness include compliant/foldable fingers [4], integrating softer materials for shock absorption [5],
and dust/water resistant designs [4]. Unfortunately, these solutions only aide gentle or moderately
intense activities, not sports for example. One improvement could be using artificial skins that change
stiffness over time to protect UL exteriors, stiffening to reduce skin damage or softening to increase shock
absorption. Meanwhile, prosthetic/socket discomfort solutions consist of socket design improvements
(e.g., integrating silicone [6], adjustable pressure chambers [7]), and sensorised sockets to quantify
patient discomfort [3]. However, silicone cannot change material stiffness to optimise RL
compression/relief (reducing abrasion risks while providing a secure limb-socket connection), and
pressure chambers and embedded sensors are not mechanically robust to daily wear. One improvement
could be an artificial skin-based prosthetic liner that could change stiffness to apply or relieve
compression (by stiffening or softening over time, respectively) around the RL. Additionally, if using
sensorised artificial skins (especially those without off-the-shelf sensors e.g., [8]) for the liner, the
increased mechanical robustness would give users and prosthetists a more contextual, in situ
understanding of user discomfort. If these were integrated into prosthetic UL exteriors, fewer off-the-shelf components would be used, decreasing the risk of damaged embedded sensors. A joint solution,
the aim of this project, is to integrate sensorised artificial skins into UL prosthetics and socket liners that
could stiffen or soften through passive contact with the environment over time, improving mechanical
robustness, durability, and comfort, depending on the materials and stimulation used.

Firstly, the NeatSkin soft sensor [8] will be adapted into a Sensorised Artificial Skin. NeatSkin measures
deformations as changes in electrical impedance of microfluidic channels, i.e. Electrical Impedance
Tomography. This approach avoids off-the-shelf sensors and can measure deformations around the limb
in the form of a socket liner or interactions with the environment when integrated with the prosthetic
hand. The Sensorised Artificial Skin will then be integrated with elements that can 'morph', i.e., the ability
of a material or surface to stiffen or soften in response to interactions with the environment, similarly to
how biological tissue and skin respond to the environmental [9] [10]. Finally, the 'morphing' feature will
be integrated into the NeatSkin to form the 'MorphSkin' and tested in prosthetic ULs and socket liners.

FARSCOPE-TU will deliver a step change in UK capabilities in robotics and autonomous systems (RAS) by elevating technologies from niche to ubiquity. It meets the critical need for advanced RAS, placing the UK in prime position to capture a significant proportion of the estimated $18bn global market in advanced service robotics. FARSCOPE-TU will provide an advanced training network in RAS, pump priming a generation of professional and adaptable engineers and leaders who can integrate fundamental and applied innovation, thereby making impact across all the "four nations" in EPSRC's Delivery Plan. Specifically, it will have significant immediate and ongoing impact in the following six areas:
1. Training: The FARSCOPE-TU coherent strategy will deliver five cohorts trained in state-of-the-art RAS research, enterprise, responsible innovation and communication. Our students will be trained with wide knowledge of all robotics, and deep specialist skills in core domains, all within the context of the 'innovation pipeline', meeting the need for 'can-do' research engineers, unafraid to tackle new and emergent technical challenges. Students will graduate as future thought leaders, ready for deployment across UK research and industrial innovation.
2. Partner and industrial impact: The FARSCOPE-TU programme has been designed in collaboration with our industrial and end-user partners, including: DSTL; Thales; Atkins; Toshiba; Roke Manor Research; Network Rail; BT; National Nuclear Lab; AECOM; RNTNE Hospital; Designability; Bristol Heart Inst.; FiveAI; Ordnance Survey; TVS; Shadow Robot Co.; React AI; RACE (part of UKAEA) and Aimsun. Partners will deliver context and application-oriented training direct to the students throughout the course, ensuring graduates are perfectly placed to transition into their businesses and deliver rapid impact.
3. RAS community: FARSCOPE-TU will act as multidisciplinary centre in robotics and autonomous systems for the whole RAS community, provide an inclusive model for future research and training centres and bring new opportunities for networking between other centres. These include joint annual conference with other RAS CDTs and training exchanges. FARSCOPE-TU will generate significant international exposure within and beyond the RAS community, including major robotics events such as ICRA and IROS, and will interface directly with the UK-RAS network.
4. Societal Impact: FARSCOPE-TU will promote an informed debate on the adoption of autonomous robotics in society, cutting through hype and fear while promoting the highest levels of ethics and safety. All students will design and deliver public engagement events to schools and the public, generating knock-on impact in two ways: greater STEM uptake enhances future economic potential, and greater awareness makes people better users of robots, amplifying societal benefits.
5. Economic impact: FARSCOPE-TU will not only train cohorts in fundamental and applied research but will also demonstrate how to bridge the "technology valley of death" between lower and higher TRL. This will enable students to exploit their ideas in technology incubators (incl. BRL incubator, SetSquared and EngineShed) and through IP protection. FARSCOPE-TU's vision of ubiquitous robotics will extend its impact across all UK industrial and social sectors, from energy suppliers, transport and agriculture to healthcare, aging and human-machine interaction. It will pump-prime ubiquitous UK robotics, inspiring and enabling myriad new businesses and economic and social impact opportunities.
6. Long-term Impact: FARSCOPE-TU will have long-term impact beyond the funded lifetime of the Centre through a network for alumni, enabling knowledge exchange and networking between current and past students, and with partners and research groups. FARSCOPE-TU will have significant positive impact on the 80-strong non-CDT postgraduate student body in BRL, extending best-practice in supervision and training.