Heat sensor allows robots to mimic human reactions to extreme heat

The device has been built by a team of experts from Liverpool Hope University, who say it’s the first sensor that can trigger this ‘sensory impulse’ that the robotics community has seen.

The researchers said their system is so robust it can measure temperature changes of 30°C per second - similar to how someone might quickly pull their hand away from the threat of being burned.

The wireless, Wi-Fi enabled sensor could have numerous real-world applications, from space exploration to surgical procedures and even creating "thermo-sensitive soft robots in the near future".

Alexander Co Abad, lead author on the study, said: “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 explorations.”

Giving robots a real ‘sense of touch’ could help them to be more adept in complex environments.

“Although psychologists often state that vision is the main way humans obtain information from the environment, when visual perception is impaired, haptic perception is the natural recourse,” Abad explained. “Even if vision is not impaired, the sense of touch often works in conjunction with visual perception.”

At the heart of the work is what’s called a ‘GelSight’ sensor - something first invented by experts at the Massachusetts Institute of Technology (MIT) in 2009 and which provides a highly detailed visual 3D ‘topography’ of any surface by processing ‘touch’ information.

It’s essentially a high-tech ‘mirror’ that provides digital feedback according to what it touches by way of a sensor and camera.

The researchers created their own, low-cost version of a GelSight sensor using a £1 cosmetic pad, which means the tech is highly accessible to a whole host of different fields.

The research focused on adapting the GelSight sensor to react to extreme heat by using ‘thermochromic’ paint, which changes colour in response to temperature changes but reverts back to normal once exposure to varying temperatures has been removed. The sensor quickly changed colour when exposed to heat greater than 50°C.

“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,” Abad said.

The team measured a response time of just 643ms for cold-to-hot and hot-to-cold, which is comparable to the withdrawal reflex response of less than one second typical of the human autonomic system to extreme heat.

“Our sensor might give robots the ability to react as humans and create thermosensitive soft robots in the near future,” Abad concluded.