A low-cost, wireless robotic sensor that mimics humans’ instinctive, automatic reaction to heat has been developed at Liverpool Hope University.
Researchers at the University’s School of Mathematics, Computer Science and Engineering have published their findings in the IEEE Sensors Journal.
PhD student and lead author Alexander Co Abad says the system can measure temperature changes of 30 degrees centigrade per second – similar to how someone might snatch their hand away from a hot object to avoid being burned.
So, why is this development important, and what applications might it have?
Researchers say it could have uses in extreme environments, such as space, or in precision applications such as robot-assisted surgery, with the potential to aid the development of a new generation of heat-sensitive softbots.
Robotic technologies that have cross-cutting applications in a variety of different fields are attractive to investors, as the payback can be considerable in both practical and financial terms.
Meanwhile, extreme environment robotics – locations that are hazardous or lethal to humans, such as space, underwater engineering, deep mining, defence, and nuclear decommissioning – are a key focus of UK robotics research.
Robots can go where humans fear to tread, but only if they are safe, secure, and controllable in those spaces, and can feed essential data back to human operators, or work autonomously.
It stands to reason that sensors which can react rapidly to sudden changes in heat could have promising applications in these fields. Giving robots a human-like sense of touch makes them more sensitive and useful in complex, challenging environments. It may also prevent damage to the robot.
Abad explains, “This feature could be useful for soft robots to act equivalent to humans’ withdrawal reflex in touching hot surfaces in search and rescue, industrial applications, and space exploration.
“Although psychologists often say that vision is the main way humans obtain information from the environment, when visual perception is impaired, haptic perception is the natural recourse. Even if vision is not impaired, the sense of touch often works in conjunction with visual perception.”
At the heart of the research is a GelSight sensor, invented at the Massachusetts Institute of Technology (MIT) in 2009, and which provides a detailed visual 3D map of any surface.
The Liverpool researchers have adapted the concept to deal with extreme temperatures.
Crucially, Abad and his colleagues, including Professor David Reid and Dr Anuradha Ranasinghe, have also created an ultra-low-cost spin on the technology based on a £1 pad and the use of thermochromic paint, which changes colour in response to temperature changes.
Abad explains: “We demonstrated that we could easily sense temperature using the hue value, by using different colours and layers of thermochromic pigments with varying thresholds of temperature on the reflective coating.
“This thermosensitive visuo-tactile sensor is the first monolithic elastomer temperature sensor and can be used to infer tactile forces based on the mechanical deformation of the gel.”
