Quantity is a quality in itself, and that seems to be the case in robotics as well. Researchers at the University of Notre Dame report that they have successfully designed and built multi-legged robots that can navigate difficult terrain and work together to perform a variety of tasks.

Nature is no stranger to the concept of collaboration. We ourselves are a good example of such collaboration at work, but insects such as ants and bees show what can be done when even small actors join forces. Robotics have long been keen to mimic such skills in their creations, and most importantly imprint them in small frames.

New research puts us on the right track towards such a goal.

Silicon swarm

“Legged robots can navigate challenging environments such as rough terrain and tight spaces, and the use of limbs provides effective body support, allows for rapid maneuverability and facilitates crossing obstacles,” said Yasemin Ozkan-Aydin, an assistant professor of electrical engineering at the University of Applied Sciences. University of Notre Dame, which designed the robots.

“However, legged robots face unique mobility challenges in terrestrial environments, resulting in reduced locomotor performance.”

The collective behavior of birds, ants and other social insect species has been a great source of inspiration for Ozkan-Aydin. She was particularly fascinated by their ability to work together to complete tasks that would be impossible for a single individual of the species. She tried to bring the same possibilities into her own creations.

While research has been done on collective behavior in flying and underwater robots, robots on land face specific challenges that the other two do not. For example, traversing complex terrain is such a challenge.

Ozkan-Aydin started from the idea that a physical connection between individual bots could be used to increase their overall mobility. The legged robots she designed will attempt to perform tasks such as moving a light object or navigating a smooth surface, but if the task proves too big for them alone, several robots will be physically linked together. to form a greater whole. multi-legged system. Together they will work to solve the problem.

“When ants collect or transport objects, and when someone encounters an obstacle, the group works together to overcome that obstacle. For example, if there is an opening in the path, they will form a bridge for the other ants to travel across — and that’s the inspiration for this study,” she said.

“Robotics will allow us to better understand the dynamics and collective behavior of these biological systems and explore how we can use this kind of technology in the future.”

Each individual bone is about 15 to 20 centimeters (6 to 8 inches) long and they are built using a 3D printer. They carry their own lithium polymer battery, three sensors — a light sensor on the front and two magnetic touch sensors on the front and back — and a microcontroller. Thanks to the magnetic sensors, they can be connected to each other. They move on four flexible legs, an arrangement that Ozkan-Aydin says reduces their need for sensors and their overall complexity.

She designed and built the robots in early 2020, and due to the pandemic, many of her experiments were conducted at home or in her yard. During that time, the robots’ skills were tested on grass, mulch, leaves and acorns. Their ability to cross flat surfaces was tested over chipboard, stairs made of insulating foam, over a shaggy carpet or over a chipboard with rectangular wooden blocks glued to it to simulate rough terrain.

During this time, Ozkan-Aydin programmed the robots so that when one of them got stuck, they would send a signal to the others to connect with him and help him traverse the obstacles together.

“You don’t need extra sensors to detect obstacles, because the flexibility in the legs helps the robot move past them,” says Ozkan-Aydin. “They can test for holes in a path, build a bridge with their bodies; move objects individually; or connect to move objects collectively in different kinds of environments, no different from ants.”

There are still improvements to the design, she explains. However, the aim was not to design the perfect robot; what she hopes is that her findings will contribute to the further development of low-cost, cooperative robots that can perform real-life tasks, such as search and rescue operations, collective transport of various objects, environmental monitoring or even space exploration. In the future, she will focus on improving the control, detection capabilities and power autonomy of the robots.

“For functional swarm systems, battery technology needs to be improved,” she said. “We need small batteries that can deliver more power, ideally longer than 10 hours. Otherwise, using this type of system in the real world is not sustainable.”

“You have to think about how the robots would function in the real world, so you have to think about how much power is needed, the size of the battery you use. Everything is limited, so you have to make decisions with every part of the machine. ”

The paper “Self-reconfigurable multi-legged robotic swarms collectively accomplish challenging terradynamic tasks” has been published published in the news Science Robotics.