Among programmers, there's a principle called DRY, which stands for "Don't repeat yourself." It's an attempt to avoid writing code that duplicates the function of other code.
DRY embodies the same resistance to needless repetition as the more common idiom, "Don't reinvent the wheel."
Among those making robots, a group that includes software and hardware engineers attempts to adhere to these principles, as can be seen in designs that borrow from nature, from the evolved forms of life on Earth.
Biomimicry and bioinspired design provide a way to avoid reinventing the wheel. The biological systems of living things have been honed through eons of Darwinian user testing.
Borrowing aspects of animal physiology isn't the only option or necessarily the best option for robot designers. For some purposes, something new may be necessary. For others, biomechanically systems can't be easily duplicated.
As MIT's Biomimetic Robot Lab notes on its website, "The complexity of the foot structure with its neuromuscular control" isn't easily duplicated with current technology.
Modelling artificial systems after natural ones can be a shortcut to mechanisms that work well enough. So popular is this approach that it has its own journal, Bioinspiration & Biomimetics. Among the robots discussed therein is the GoQBot, modelled after a caterpillar that can form its body into a wheel when it needs to roll.
Why reinvent the wheel when you can simply be the wheel?
Matthew Travers, a systems scientist at Carnegie Mellon University's Robotics Institute, in a phone interview said bioinspired and biomimetic systems have their place. "It's a good approach," he said. "Ultimately, there's a lot of variability in terms of approaches."
In the lab where Travers works, the focus is mobility and biological systems have a lot to offer there. "As far as mobility is concerned, bioinspiration is an obvious route to cake," he said.
Asked where nature might not be the best guide for engineering, Travers recounted remarks made by UC Berkeley professor Bob Full, director of the Poly-PEDAL Laboratory and Center for interdisciplinary Bio-inspiration in Education and Research (CiBER), as well as the editor-in-chief of Bioinspiration & Biomimetics.
Full, in an email, said Travers had captured the spirit of what he'd said but offered a more complete quote: "We should not blindly copy Nature. We must translate the principles and analogies from Nature that are advantageous, and integrate them with best human engineering to design something better than Nature. The largest bird's wingspan was about 30 feet, so I couldn't fly here on it. Planes go far beyond Nature's abilities."
"Our building blocks as engineers are fundamentally different that those of nature," said Travers.
In Biomimicry: Innovation Inspired By Nature (William Morrow, 1997), Janine Benyus wrote, "Unlike the Industrial Revolution, the Biomimicry Revolution introduces an era based on not what we can extract from nature, but what we can learn from her." By copying nature's designs, she observes, we have solar cells inspired by leaves, perennial grains inspired by tallgrass, and durable ceramics inspired by mother-of-pearl.
Nature still has much to teach us as we strive to improve on its designs. For roboticists, George Santayana's famous admonition, "Those who cannot remember the past are condemned to repeat it," should be rephrased, "Those who study the past have the privilege to borrow from it."
Here are a few of the many biologically-inspired robots that have been developed in recent years. And there are many more to come.