Shape sensing textile for orthotics - SmartSensOtics

Orthotic products are of great importance to a number of people around the world. The process of fabricating orthoses is well established, but depends on a time and resource consuming plaster cast method developed over 100 years ago. This is associated to a number of reasons e.g. the fact that an Orthotist has to shape the patient's body to define the shape of an orthosis. In particular in the case of children or patients with joint contractures and anatomical deformities, such as those affected with neurological and neuromuscular medical conditions, such as Cerebral Palsy. This issue prevents the efficient application of MRI, CT or optical imaging techniques, because these require extensive post-processing to discriminate between the patient's body and the Orthotist's hands. Additionally, such imaging equipment is expensive and requires a highly technicians. Hence, providing orthoses is only possible if, hospitals, expensive medical scanners, consumables, and workshops are accessible. This is not the case in developing countries, consequently orthoses in LMICs are often fabricated form scrap such as old water canisters.

Recently, the development of flexible, soft electronics, as well as the spread of wearable electronic devices has made significant progress. Here we want to develop a smart, portable and stretchable textile sleeve with integrated sensors connected to a smartphone to realize an entirely new, versatile, and wearable body shape imaging technique. The digital limb models by our system can then be used for the computer aided fabrication of customized orthotics, without the need for significant infrastructure.
Our smart textile will contain an active array of stretchable strain sensors to measure the deformation of the textile itself. The knowledge of the strain distribution inside the tight fitting stretchable textile when worn over a limb or body part will be used to determine the exact three-dimensional shape of the limb. Any external influence such as the force applied by the Orthotist will also be quantified, but will not interfere with the shape measurement.
The development and fabrication of biocompatible, polymer based strain gauges able to measure strain of >200% will be done in the semiconductor manufacturing cleanroom at the University of Sussex. This cleanroom is optimized for the fabrication of flexible electronic thin-film devices on plastic substrates. The sensors will then be unobtrusively integrated into an elastane fabric using embroidery, and interconnected using conductive yarns. We will evaluate the required sensor density to achieve a measurement resolution sufficient for the fabrication of orthotic products. In a next step, the acquired sensor data will be proceed on a smartphone to automatically generate a three-dimensional model of the imaged body part. Hence no professionals, additional infrastructure or consumables are needed to support the Orthotist in treating the patients. The generated digital model can then be electronically sent to a manufacturer or used to produce the orthosis in a mobile 3D printer, whereas printing of a mould for the conventional fabrication of orthoses, and direct printing of an orthosis will be evaluated. John Florence Ltd. will be responsible for the fabrication of the Orthotic products and the evaluation of their quality.

To assess the technology as a whole, and to define workflows for the fabrication of orthotic products in rural areas in developing countries, the Kenya Medical Training College and the Ability Therapy Place will support us evaluate the developed wearable in Kenya.
The shape and force sensing technology developed here will not only revolutionise the fabrication of orthoses, but also influence the development of other medical products such as prostheses, monitoring of diseases related to the shape, size or deformation of the skeletal system or soft tissue, and even the realization of artificial sensor skins for interactive soft robots

Impact and timeline
By the end of this project, the technology for a flexible and biocompatible active sensor array will be developed and used to realize a demonstrator of a wearable textile integrated body shape sensor. Together with the associated data processing, this sensor will be able to generate a digital 3D limb model for the smart fabrication of orthotics. The use of 3D printers in the orthotics fabrication process will be evaluated. It will also be demonstrated that this sensor textile can be operated in Kenya. At this stage we expect a TRL between 3 and 4. From here on two parallel routes for the further development and application of the technology are foreseen. Directly after the project the developed demonstrator can be augmented to make it more reliable, and easier to use which enable its application in rural areas in Kenya. Around 3 to 5 years later, this will lead to entirely mobile orthotics workshops in LMICs combining the developed body shape sensing technology with computer aided manufacturing techniques. At the same time, the body shape scanning technology will be more advanced to allow dynamic high precision measurements which will enable its evaluation for UK applications as a convenient body shape sensor for orthotics, prosthetics, fitness applications, or as motion capturing system for gaming, or rehabilitation. Another way this project will create impact is the development of a generic technology to realize flexible large-area sensor arrays. In the time up to 5 years after the project, the developed active matrix structure can be equipped by a set of other stretchable sensors (e.g. for temperature, chemicals, or PH) which are conditioned using an updated version of the microcomputer. In the long term (5-7 years after the project) such arrays will lead to the realization of truly large-area multi-modal sensors systems, which are mechanically flexible and unobtrusive. This is a requirement for the fabrication of soft artificial sensor skins and tattoos for healthcare, robotics and prostheses. At this point the two impact paths of this project will again join by revolutionizing the fabrication of customized medical supports and by enabling the development of artificial limbs with human like sensing abilities.

Orthotics manufacturers and patients
The first beneficiary will be our partner John Florence Ltd. The developed technology will open a way to fabricate orthotics without the need for expensive and bulky plaster casts, and to scan the body shape of patients without expensive MRI, CT and optical scanners (and without labour intensive post processing if the body part is manually corrected). In the medium term also clinicians will benefit by a change of the practise orthotics and prosthetics patients are treated. Finally, the comfort for patients will be improved by the use of the unobtrusive and fast textile body shape sensor instead of plaster of Paris mould. In developing countries patients and physicians will start to benefit earlier (around 5 years after the project) because there the textile sensor system does not have to compete with expensive conventional scanners. Here physicians are able to supply orthoses to patients and to improve their mobility.

Skilled workforce
Within the time frame of the project, the team (postdocs, and associated students) will gain useful and transferable skills, especially analytical, presentation and organizational skills applicable to several sectors, as well as subject specific skills (Micro technology, Data processing) essential for the electronic systems industry which is an important employer in the UK.

Additional impact
In the long term, also a wider public will benefit from techniques able to quantify the size of body parts to evaluate fitness levels (build up of muscles) or to fabricate customized clothes. Furthermore researches active in context recognition or robotics will profit from motion capturing systems and artificial sensor skins.