Robots are good at repeating tasks, but what they lack is the awareness to pull back when necessary. But a new development from researchers in China suggests that this may soon change.

Scientists at Northeast Normal University have created a soft, jelly-like electronic "pain nerve" that behaves in a surprisingly human way. Unlike most robot sensors, which work like simple switches, this one can sense different levels of pressure. Besides registering touch or no touch, it can also tell the difference between mild contact and something that should trigger a fast retreat.

The design goes further — when the artificial nerve is damaged, it becomes more sensitive. As it recovers, that sensitivity slowly fades. This mirrors how human nerves behave after injury. It also allows a robot to protect itself while it is vulnerable, rather than forgetting the damage as soon as it occurs.

At the heart of the system is a component called a memristor. This is an electronic device that remembers what has happened to it before. Most memristors switch between two states. The version used here has 16 stable levels. Each level represents a different degree of pain, closer to a dimmer switch than a light switch.

The nerve also relies on gelatin, a protein related to collagen. Gelatin can carry ions, much like living tissue. When warmed, it can also heal itself. In this case, heating to 60 degrees Celsius allows the material to re-bond after damage. That temperature would harm living cells, but it poses no problem for machines.

In tests, the team connected the sensor to a mouse's sciatic nerve. The device triggered a muscle response without involving the brain, much like a natural reflex.

robots / innovation