Wearable Assistive Materials

WAM is a project which started from asking a question about what would make a transformational difference to someone who is experiencing difficulties in walking. The answer was to be able to walk without visible (or audible) assistance. Following some initial work in an EPSRC project called RELEASE, WAM is starting on the road to developing just this sort of assistive technology: an exoskeleton that can be worn and that can also act as a muscle so that it can support the whole walking cycle, providing support and control to the user and enabling them to walk otherwise unaided. We have selected some of the likely possibilities from those explored during the RELEASE project and WAM will develop these further, combine them and test them against the strength, stiffness, flexion and strain requirements of the walking process. Three technologies will be explored in parallel: (1) using Vanadium Oxide (V2O5) as a chemical actuator, (2) using magnetic gels as a dynamic controllable mechanism and (3) using interlockable ceramic tiles as a surface medium.

V2O5 is able to flex when exposed to an electrostatic potential and can exhibit strength (about 10 times the strength found in skeletal muscle) so this would seem to be a useful substance to use as the basis for an actuator. Macroporous magnetic gels can be used to compress rapidly under a magnetic field to deliver drugs (by squeezing the drugs from the pores as the material compresses under the influence of an induced magnetic field). Interlockable ceramic tiles can provide the stiffness needed for the rigidity needed by a skeleton, but once unlocked an allow the structure to bend in a required direction.

These will be tested separately and in combination to see if the V2O5 working with the magnetic gel could act as a sufficiently strong actuator and key for the locking/unlocking mechanism so that the material can demonstrate sufficient strength, stiffness and strain capabilities to be worth scaling up in a future project to assist walking. Other possibilities would also be available from such material - it does not have to be used only for walking as it could be used for other joints which can need support but which also need to bend - elbow, wrist, ankle as well as knee are all candidates for such support. Also, it might provide an interesting support where it is desirable to make the assistance variable - when the person needs support and when they would benefit from being encouraged to take on the activity themselves. A variably flexible material of this sort would therefore be of use in conditions such as limb fractures (where absolutely fixed support is essential at one point on the process, but rehabilitation of associated muscles would be beneficial as the facture is healing, but is still weak, before the fixed support can be removed) or conditions such as Carpal Tunnel Syndrome where support needs might vary. While the technological work is underway we will be working with a patients' group and a group of clinicians to understand more about what end users might be looking for in their assistive technology and how this particular type of support might be useful for them. It is important to realise that this is a novel way of providing dynamic support for activities such as walking and thus there is a sense of all sides needing to understand how best to use the technology as it emerges from the laboratory.

The present project will not deliver the full working prototype of a walking support system, but it will develop, test and show what can be done in terms of the material and its control system and the extent to which this approach to actuation of locomotory support could be achieved. The final tests will show how much stiffness and strength it can deliver and thus whether or not this is the right way to proceed in further projects.

WAM is an early-stage (TRL 1-2) project, so we do not expect products to emerge from the project itself, but it provides the essential basic work from which novel assistive technology products will follow in due course. Therefore the impacts to be achieved from WAM are in the long term. These will be in the form of assistive technology and materials development.

Assistive Technology (AT)
WAM is generating a new approach to AT, namely that the possibility of making active support for actions that a person currently cannot - or can only with difficulty - make on their own, but that can also adjust the degree to which the support is provided. This allows for a number of possibilties in terms of rehabilitation and therapy. First, it would be possible for adjustments to be made during use. This could allow, for example, a support for a limb fracture, which is currently static, to be able to be adjusted to stimulate muscle use while the support is still in place to support the healing process and thus speed up recovery. Secondly, it allows for the support to be varied in use in order to encourage/stimulate natural muscular activity so that the AT device does not replace the natural process, but rather supplements it as required and stimulates it to become more proficient over time. Thirdly, it could provide active support for complex actions - walking, arm movements, neck movements - for people who are currently unable to achieve these at all. These types of impact on therapeutic activity will be discussed with patients and clinicians throughout the present project and the means for translation will be developed in order to be ready as the technology develops. UCL, together with UCL Partners, has 25 hospitals, including the national tertiary referral orthopaedics hospital (RNOH), and the UCL Institute of Biomedical Engineering is setting up a formal translation assistance system to accelerate translation of all biomedical engineering research into clinical practice. WAM would be inserted into this process so translation should be rapid. In addition, ASPIRE, together with its patient groups, will enable us to pursue the use of the technology directly with patients.

Materials development
WAM's ability to function as a dynamic but flexible external support system capable of supporting activities such as wrist and arm flexing, knee and hip bending, as well as supported neck rotation presents new opportunities for smart materials in other areas both within the healthcare technology field and elsewhere. We will explore how well the concept would work with other applications in the aerospace, automotive, and white goods industries, where such flexibility might offer new opportuities for supporting mechanisms which require changes in stiffness, strength and strain as part of normal operation. The interest of URT in being involved in the project shows that an innovative composites company sees some value in entering this market.

We will also develop new testing methods, new ways of analysing the interactions between pedestrians and their immediate environment so that sufficient knowledge can be gained to extend the capabilities of the assistive technology. This will potentially turn into new products and techiques which could be exploited, not only within materials and research but also in the application of rehabiltation therapies.

WAM is thus a transformative project, exploring new ways of achieving a different type of support for people requiring assistive technology to help them move around.

The impact is not only within the UK. The generic problems being tackled by WAM also apply elsewhere in the world: China, for example, currently has 67 million people using wheelchairs and is expecting a similar increase in population as the rest of the world because of increasing life expectancy.