http://www.digitaljournal.com/tech-and-science/science/a-sense-of-touch-allowing-robots-to-feel/article/502679

A sense of touch: Allowing robots to feel

Posted Sep 17, 2017 by Tim Sandle
Researchers have devised an artificial skin that allows a robot to sense ‘touch’, to a degree in a way that is similar to people. This is a step forward in the development of robotics and will be of interest to developers.
Touch ID on the iPhone 5s
Touch ID on the iPhone 5s
Kārlis Dambrāns
The development has taken place at the University of Houston and relates to an advancement with stretchable electronics. This is in the form of a material that can act as an artificial skin. The skin allows a robotic hand to sense the difference between something that it hot and something that is cold. This type of technology will be of interest to those developing biomedical devices.
The basis of the technology is a type of semiconductor contained within a rubber composite (silicon-based polymer known as polydimethylsiloxane) format. Power to the semiconductor is provided through nanowires. This structure enables the electronic components to retain functionality as the material is stretched. Tests show that the material could be stretched by 50 percent without loss of functionality. The trials are the first to allow a semiconductor to be placed within a stretchable material without any drop in performance.
The reason why developments with semiconductors and stretchable electronics have been hampered is because they are brittle and not easily accommodated within mechanical systems. The consideration of other materials also pushes future devices in a direction where they would become prohibitively expensive.
The success of the prototype means that the mew way of generating can upscaled for commercial production. The person behind the invention is Professor Cunjiang Yu. In an interview, the researcher explains: "Our strategy has advantages for simple fabrication, scalable manufacturing, high-density integration, large strain tolerance and low cost.”
Building on the strechability concept Yu’s research team went onto create an electronic skin. The ski was then used to show how a robotic hand can readily sense the temperature of a surface. In on trial a cup that was hot and cup that contained iced water were used. The trial was successful.
In a separate study using the skin, the researchers demonstrated that the device is able to interpret computer signals sent to the hand and reproduce the signals as American Sign Language. This was in a form that a person could interpret.
As well as acting as a skin for robots, the material can also be used for various soft wearable electronics, such as health monitors and medical implants. The advance in robotics has been published in the journal Science Advances, with the research paper titled “Rubbery electronics and sensors from intrinsically stretchable elastomeric composites of semiconductors and conductors.”