Computing with Spider Webs

 

How appropriate, then, that new research on spider webs may lead to novel sensor technology that measures vibrations and flow.  Inspired by the capability of spiders to build their own signal processors, researchers with the universities of Bristol and Oxford intend to apply their study results toward developing robotic prototypes capable of deploying new sensor technology on demand.

 

The scientists hope their study on spider webs yields insights on the way we think about the morphological features of biological sensors, in addition to maybe opening new pathways for bio-inspired sensor design.

 

The concept of outsourcing computation to a physical body (e.g., from the brain to another part of the body) is usually referred to as morphological computation, which can be observed in all biological systems, say the researchers.

 

This is a design approach, often used in robotics, which considers the body of a robot crucial for any intelligent behavior. Like in the case of morphological computation-based robot designs, spiders seem to defer computational tasks to a morphological structure, such as, the spider outsources pattern recognition to the web.

 

Spiders have sensitive mechanoreceptors on their legs that allow them to measure vibrations. They also probe for activity on their webs by sending vibrations and observing how the web responds in the form of vibration patterns. This process, the researchers believe, suggests the web is not only a static, passive structure to catch prey, but also an active sensor that actively contributes to the pattern recognition task to locate and categorize everything occurring in the web.

 

"The idea of intelligent morphological structures is not just useful for spiders, but can be developed into novel, intelligent sensor technologies, especially for vibration and flow sensors," says study leader Helmut Hauser, lecturer in robotics in the department of engineering mathematics at the University of Bristol.

 

The interdisciplinary project between researchers at the two universities will combine biological experimentation, simulation and mathematical modelling to better understand how the sophisticated structure of spider webs carry out computation.

 

 

Spiders’ webs have evolved over hundreds of millions of years and can be surprisingly complex. Their obvious functionality is to catch and hold prey. However, their remarkably complex structure suggests they can do even more.

 

The web could potentially serve as a signal-processing device. It could help the spider to locate and categorize its prey and other events like broken threads or mates. In other words, the spider might use its web as a computer.

 

"We believe on-demand deployable morphology-based computational devices is of great interest for robotics," Hauser says. "Potential uses for the technology include maintenance robots that swarm through tubes building flow sensors at key points to identify irregularities, or climbing robots that construct vibration sensors at strategic places on buildings to detect earthquakes or structural failure."

 

The researchers suggest the spider’s web is highly likely to be a nonlinear, dynamic filter, i.e. a pre-processing unit that helps the animal to interpret vibration signals.

 

"The web’s dynamic properties and its complex morphological structure naturally enables the mixing of vibration signals in a nonlinear fashion at their nodes, damping of unwanted frequencies, and even exhibiting memory by transmitting and echoing the signals throughout the network," says a report describing the study.

 

Fritz Vollrath, a professor at Oxford's department of zoology, adds, "It will be interesting to see how far spiders are able to develop their catching-nets into gossamer-sensors, and how accurate a particular web can inform its spider about prey caught and about predators on the prowl."