Robots have become remarkably good at seeing and moving, but their sense of touch still lags far behind that of humans.
A new technology developed by researchers at the University of Cambridge could help close that gap.
The team has created a miniature tactile sensor that allows robots to feel pressure, detect slipping objects, and sense surface textures in ways that resemble human touch.
The new “artificial skin” is made using advanced materials, including graphene and liquid metal composites.
Graphene is a special form of carbon that is only one atom thick and is known for its strength and excellent electrical properties.
By combining graphene with tiny metal droplets and nickel particles inside a flexible silicone material, the researchers created a soft sensor that can respond to very small forces.
Their findings were published in the journal Nature Materials.
Human fingertips are extremely sensitive because they contain different types of nerve endings called mechanoreceptors.
These receptors allow people to feel pressure, vibrations, and textures all at the same time.
Reproducing this complex sense of touch in machines has been very difficult. Many existing robotic touch sensors are bulky, fragile, or unable to tell the difference between different types of force.
The Cambridge research team took inspiration from the microscopic structures found in human skin. They shaped their new material into tiny pyramid-like structures, some only about 200 micrometers wide—roughly twice the width of a human hair. These small pyramids concentrate force at their tips, making the sensor extremely sensitive while still allowing it to measure stronger pressures.
The sensor is so precise that it can detect forces as small as the weight of a grain of sand. Compared with other flexible touch sensors, the new design significantly improves both sensitivity and size.
Another important feature is the sensor’s ability to detect the direction of forces. In addition to measuring direct pressure, it can sense sideways forces that occur when an object begins to slip. Four tiny electrodes placed under each pyramid measure changes in electrical signals, allowing the system to calculate the full three-dimensional force acting on the surface in real time.
To demonstrate the technology, the researchers attached the sensors to robotic grippers. The robots were able to pick up fragile objects, such as thin paper tubes, without crushing them. Because the sensors can detect slipping, the robot automatically adjusts its grip as needed.
The technology may also be useful in fields that require extremely precise touch. For example, small arrays of these sensors could help robots analyze the weight, shape, and material properties of tiny objects. This capability could benefit areas such as microsurgery or miniature robotic systems where traditional sensors are too large.
Beyond robotics, the new artificial skin could improve prosthetic limbs. Modern prosthetic hands are becoming more advanced, but many still lack realistic tactile feedback. Highly sensitive touch sensors could help users better control artificial limbs and interact with objects more naturally.
The researchers believe the sensors could be made even smaller in the future, potentially approaching the density of touch receptors found in human skin. Future versions may also detect temperature and humidity, creating a more complete artificial sense of touch.
As robots move beyond factory floors and into homes, hospitals, and everyday environments, technologies like artificial skin may help them interact with the world more safely and naturally.
