Multimodal Artificial Skin Inspired by Human Skin

Innovation: Academia

Technical University of Munich

2019

Image: Nsey Benajah / Unsplash / CC BY SA - Creative Commons Attribution + ShareAlike

Sense Touch and Mechanical Forces in a Living System

Perceiving touch enables living systems to detect other living systems around them and environmental conditions, such as air movement, water currents, and temperature. This ability can help them sense danger as well as opportunity, as when a Venus flytrap’s hairs sense the presence of an insect to eat. Sometimes, a living system senses touch or mechanical forces at a coarse scale; other times, at a sensitive scale that detects very subtle differences. For example, a human elbow is not nearly as sensitive to textures as human fingertips. Fingertips have dermal ridges and many nerve endings that increase sensitivity, enabling them to explore the environment in detailed ways. Elbows don’t need to sense at that level of detail.

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Sense Temperature Cues From the Environment

Some living systems use their ability to perceive temperature to find prey or avoid predators, or as a way to gain information about their environment, such as whether they are near a warm or cold place. Temperature gradients can be subtle and modulate as they travel through water, air, or solids. Living organisms must therefore have a variety of thermal sensors appropriate to a given medium (liquid, gas, solid). Some even have a way to “visualize” a signal’s source. For example, the rattlesnake has heat sensors with thousands of nerve endings located in pit-shaped holes on each side of its face. The sensitivity of the pits overlaps, giving the snake a bifocal image of the heat’s source.

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Artificial skin from Technical University of Munich uses an event-based processing system to accurately perceive its surroundings.

Benefits

Sensitive
Reduced energy usage

Applications

Medical treatment
Medical implants
Robotics

UN Sustainable Development Goals Addressed

Goal 9: Industry Innovation & Infrastructure

The Challenge

Since the early days of the robotics field, developing artificial skin technology has been an area of interest. Effective robotic skin would grant robots a sense of touch similar to that of humans, enabling them to be physically interactive and ensuring that they are safe to be around humans. However, human skin has approximately five million touch receptors. Due to physical size limitations and insufficient information processing capabilities, so far robotic skin cannot contain the density of sensors that would be needed to match the sensitivity of human skin.

Innovation Details

The artificial skin consists of 1-inch diameter hexagonal cells that are each wrapped with a microprocessor and sensor. The sensors detect contact, acceleration, proximity, and temperature, which the ‘skin’ then processes through an event-based system. Essentially, the individual cells only transmit information when values change, reducing processing effort by up to 90%. This event-based system is the key to efficient robotic skin, enabling sensors to process greater amounts of information faster within a compact organization. Robots with this skin are autonomous, meaning they are not dependent on any external computation.

Biomimicry Story

Human skin senses texture, temperature, and pressure in the surrounding environment partly through mechanoreceptors, specialized nerve cells that project into the outer layers of the skin. These receptors are stimulated by a physical change in the environment, such as the movement of the skin along a surface or material. When a change is detected, mechanoreceptors transmit tactile information to the brain.

See Related Strategy

close up view of a human finger tip of a white person with a blue background

Biological Strategy

Fingertips Increase Sensitivity to Touch

Humans

Fingertips increase touch sensitivity due to mechanoreceptors underneath the surface of the skin

Biological Strategy

Healing, Feeling, Skin Does It All

Humans

Multiple components allow skin to heal, feel, and more.

References

Journal article

A Comprehensive Realization of Robot Skin: Sensors, Sensing, Control, and Applications

IEEE Explore

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