A robot can be soft but great in a knife fight


In the cutting-edge field of soft robotics, self-healing is a prime capability.


A human hand and a robot hand.
A human hand and a robot hand.
Terryn et al., Sci. Robot 2017

If you cut a robot it won’t bleed, but, thanks to research coming out of Belgium in the future it may well heal itself.

A team led by Seppe Terryn of Vrije Universiteit Brussel has overcome one of the more challenging aspects of the growing field known as “soft robotics”.

The field concerns building intelligent machines with external coverings made of impressionable, malleable materials. Such soft and squishy skins have a number of advantages when the robots are deployed in pressure-sensitive dynamic environments.

For instance, they are better able to absorb sudden shocks and impacts. They are also well suited for robot-human interactions, where, for example, the machine may be tasked with tending to, or moving, a hospital patient or child.

No way to treat a robot: a researcher cuts the hand of a soft robot.
No way to treat a robot: a researcher cuts the hand of a soft robot.
Terryn et al., Sci. Robot 2017

However, the main drawback for soft robotic coverings is that they are highly susceptible to damage. Sharp objects, in particular, can slice them open, reducing (or even ending) their efficiency, leading to expense and downtime to facilitate repairs.

Terryn’s team has developed a soft-robotic material made entirely of temperature-sensitive elastic material that is capable of self-healing. In experiments conducted on a purpose-built robotic hand, the scientists report in the journal Science Robotics that the substance is able to completely eradicate damage caused by a scalpel blade in just 40 minutes.

The material is made using cross-linked Diels-Alder polymers, large molecules that are heat-sensitive. When exposed to mild heat – about 80 degrees Celsius – the polymer lattice temporarily breaks down and then knits back together when the temperature falls to about 25 degrees Celsius, effectively repairing damage in the process.

The researchers report finding no discolouration or scarring at self-healed wound sites. Recovered function was estimated at 98–99%.

As an added bonus, the elastomer coating is reported to be easily recycled. Dissolving it chloroform resulted in an 81% recovery rate.

  1. http://robotics.sciencemag.org/lookup/doi/10.1126/scirobotics.aan4268
  2. http://robotics.sciencemag.org/lookup/doi/10.1126/scirobotics.aan4268
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