Engineering Fellowships for Growth: Printable Tactile Skin

The societal needs such as helping elderly and rapid technological advances have transformed robotics in recent years. Making robots autonomous and at the same time able to interact safely with real world objects is desired in order to extend their range of applications to highly interactive tasks such as caring for the elderly. However, attaining robots capable of doing such tasks is challenging as the environmental model they often use is incomplete, which underlines the importance of sensors to obtain information at a sufficient rate to deal with external change. In robotics, the sensing modality par excellence so far has been vision in its multiple forms, for example lasers, or simply stereoscopic arrangements of conventional cameras. On other hand the animal world uses a wider variety of sensory modalities. The tactile/touch sensing is particularly important as many of the interactive tasks involve physical contact which carry precious information that is exploited by biological brains and ought to be exploited by robots to ensure adaptive behaviour. However, the absence of suitable tactile skin technology makes this task difficult.

PRINTSKIN will develop a robust ultra-flexible tactile skin and endow state-of-the-art robotic hand with the tactile skin and validate the skin by using tactile information from large areas of robot hands to handle daily object with different curvatures. The tactile skin will be benchmarked against available semi-rigid skins such as iCub skin from EU project ROBOSKIN and Hex-O-Skin. The skin will be validated on at least two different industrial robotic hands (Shadow Hand and i-Limb) that are used in dexterous manipulation and prosthetics.

The robust ultra-thin tactile skin will be developed using an innovative methodology involving printing of high-mobility materials such as silicon on ultra-flexible substrates such as polyimide. The tactile skin will have solid-state sensors (touch, temperature) and electronics printed on ultra-flexible substrates such as polyimide. The silicon-nanowires based ultra-thin active-matrix electronics in the backplane will be covered with a replaceable soft transducer layer. Integration of electronic and sensing modules on a foil or as stack of foils will be explored. 'Truly bottom-up approach' is the distinguishing feature of PRINTSKIN methodology as the development of tactile skin will begin with atom by atom synthesis of nanowires and finish with the development of tactile skin system - much like the way nature uses proteins and macromolecules to construct complex biological systems. This new technological platform to print tactile skin will enable an entirely new generation of high-performance and cost-effective systems on flexible substrates. Fabrication by printing will have important implications for cost-effective integration over large areas and on nonconventional substrates, such as plastic or paper. Printing of high-performance electronics is also appealing for mask-less approach, reduced material wastage, and scalability to large area. The proposed programme thus has the potential to emulate yet another revolution in the electronics industry and trigger transformation in various sectors including, robotics, healthcare, and wearable electronics.

PRINTSKIN will develop tactile skin that will be critical to enable future robots to engage in highly interactive tasks such as caring for the elderly. Feedback from the tactile skin project will shape the way society interacts with robotic devices as robots will be able to gather rich contact information and think, act, and react like humans. The impacts of this multidisciplinary research will be seen in academia, public sector, industry, social enterprises, general public, schools and more.

Near-term, the tactile skin will result in new research foci in robotics allowing multiple contact points or contacts from the whole body to be exploited to carry out manipulation tasks in cluttered environments. Tactile skin will enable neuroscientists to understand the functioning of receptors in human skin. Together with ultra-thin bendable electronics implanted in the brain, tactile skin will enable in long-term the neural control of artificial limbs and new biomimetic technologies. Equipped with tactile skin the robots will be safe interactive learning tools that stimulate the imagination of children. For example, due to lack of emotions in robots autistic children find robots less threatening than their teachers and easier to engage with. We will see quick benefits of tactile skin in areas such as teleoperation where tactile feedback enables extension of feelings. Similarly, the impact in surgery will be quick as surgical instruments covered with ultra-thin tactile skin will allow surgeons to feel tissues inside a patient's body - eventually improving diagnostics and monitoring capabilities. I believe in the long-term, the ultra-flexible tactile skin will bestow sensory feeling to prosthetic limbs and improve lives of amputees.

PRINTSKIN will also bring about profound impact through the new printing methodology for the tactile skin, which will result in a new generation of high-performance and cost-effective flexible electronics. The paradigm of electronics manufacturing and prototyping will change with small-scale manufacturing, capable of printing high-performance circuits straight from the computer, replacing the large manufacturing centres based overseas. The cost reduction will have enormous impact on schemes such as barcodes to track objects in supermarkets. The possibility to develop identity tags (e.g. RFIDs) with performance on par with Si and cost on par with existing barcodes will drive replacement of some 15 trillion barcodes in existence today. This will significantly boost new areas such as the internet of things and big data, where tools such as RFID will be needed to wirelessly track objects. The technology affordability could lead to changes in policies e.g. taxation system of UK could be based on real-time data collected from RFIDs attached to consumed products. With reduced electronic waste, printing methods are also environment friendly. If appropriate advances can be made to make printed electronics a commercial reality, this will open up the field to a new skill base in the printing community who would not normally associate themselves with electronics.

There is significant gain in printing of high-performance devices, as many new applications which will almost inevitably - by virtue of ever-demanding end-user - supersede the solid-state IC, just as the IC replaced discrete circuit board electronics. These include intelligent packaging, conformal electronics (e.g. in automotive applications), wearable electronics, smart windows including antenna for wireless communications, medical sensors and inorganic thin film solar cells. There is great potential in the UK to establish companies based on such end products. Summarising, PRINTSKIN has the potential to start another revolution in microelectronics and will trigger transformations in robotics and similar areas.