To better imitate humans, these robots cover themselves with living skin

Japanese researchers have developed a method to cover robots with living skin, similar to human skin.

Applying human skin properties to robots allows them to more faithfully transcribe emotions and communicate more realistically.

To adapt human skin to robots, researchers used a new technique based on perforation-type anchors to attach biological tissue to the robotic structure.

These anchors are inspired by human skin ligaments, which are small structures of collagen and elastin connecting the skin to underlying tissues.

Why use living skin on robots?

Human skin has many useful properties for robots, including tactile sensitivity, the ability to self-repair, and a realistic human appearance. In unpredictable environments, robots can become scratched or damaged. The skin’s ability to repair itself is therefore crucial to extending the lifespan and effectiveness of robots.

The researchers obtain synthetic skin by mixing human skin cells grown in collagen. This gel is then applied to a 3D printed resin base and this is where the perforation-type anchoring comes in.

The usefulness of perforation type anchoring

The surface of this resin structure is dotted with small V-shaped holes in which the synthetic skin gel is housed. These are the perforation type anchors that will mimic human skin ligaments that allow the skin to attach securely to underlying tissues while remaining flexible to achieve facial expressions and body movements.

A water vapor plasma treatment then takes place to make the surface of the device more hydrophilic, thus improving the penetration of the gel into the anchors. This step is essential to ensure a solid fixation of the skin on the surface of the robot, even in hard-to-reach areas.

A more efficient process

The researchers first tested the effectiveness of the anchors using 3D facial molds covered with living skin. They demonstrated that the punch-type anchors were more stable in holding the skin in place compared to previously used methods. Contraction tests validated that the anchors prevented the skin from retracting excessively, which is crucial for maintaining skin integrity over the long term.

Tensile tests were performed to measure the strength of the anchors. This determined that larger diameter anchors increased the tensile strength, although a balance must be found between the size of the anchors and the space they take up on the device.

Synthetic skin, an idea that is not yet sustainable enough

This new perforation-type anchoring method represents a significant advance in the field of biohybrid robotics. By mimicking the structure of human skin ligaments, this technique allows living skin to be securely attached to robotic surfaces, while maintaining the flexibility needed for facial expressions and movements. This paves the way for more realistic and functional robots that can adapt and repair themselves in complex environments.

However, Japanese researchers point out that synthetic skin is not sustainable at present. It is devoid of nerve networks and blood vessels. Without nutrients and moisture, it does not survive long in the open air.