A ‘brainless’ robot that can overcome complex obstacles

Researchers who created a soft robot that can navigate simple mazes without human or computer guidance have now built on that work, creating a “brainless” soft robot that can navigate more complex and dynamic environments. The paper, titled “Physically Autonomous and Intelligent Soft Robotic Maze,” was published Sept. 8 in the journal. Science advances.

“In our previous work, we demonstrated that our soft robot was able to twist and turn through a very simple obstacle course,” says Ji Yin, co-author of a paper on the work and associate professor of mechanical and aerospace engineering. Engineering at North Carolina State University. “However, it was only able to turn if it encountered an obstacle. In practice, this meant that the robot could sometimes get stuck, jumping back and forth between parallel obstacles.

“We have developed a new soft robot that is able to turn on its own, allowing it to make its way through twisting mazes, and even overcome moving obstacles. This is all done using physical intelligence, rather than being guided by a computer.”

Physical intelligence refers to dynamic objects – such as soft robots – whose behavior is governed by their structural design and the materials they are made of, rather than directed by a computer or human intervention.

As with the previous version, the new soft robots are made of ribbon-like liquid crystal elastomers. When the robots are placed on a surface that is at least 55 °C (131 °F), which is hotter than the surrounding air, the part of the tape that is in contact with the surface shrinks, while the part of the tape exposed to the air shrinks. This results in a rolling motion. The warmer the surface, the faster the robot will spin.

However, while the previous version of the soft robot had a symmetrical design, the new robot has two distinct halves. Half of the robot is a twisting bar that runs in a straight line, while the other half is a tighter twisting bar that also loops around itself like a spiral staircase.

This asymmetrical design means that one end of the robot exerts more force on the ground than the other. Think of a plastic cup that has a mouth wider than its base. If you roll it across the table, it doesn’t roll in a straight line, it makes an arc as it travels across the table. This is due to its asymmetrical shape.

“The concept behind the new robot is fairly simple: Because of its asymmetrical design, it spins without you having to touch anything,” says Yao Zhao, first author of the paper and a postdoctoral researcher at NC State. “So, while it still changes directions when it comes into contact with an object – allowing it to navigate mazes – it cannot get stuck between parallel objects. Instead, its ability to move in arcs allows it to move freely on its way. “.

The researchers demonstrated the ability of a soft, asymmetric robot design to navigate more complex mazes — including mazes with moving walls — and enter spaces narrower than its body size. The researchers tested the new robot design on a metal surface and in sand. A video of the asymmetric robot in action can be seen below:

“This work is another step forward in helping us develop innovative approaches to designing soft robots—particularly for applications where soft robots will be able to harvest heat energy from their environment,” says Yin.

The paper’s first author is Yao Zhao, a postdoctoral researcher at NC State. Hao Su, associate professor of mechanical and aerospace engineering at NC State, is a co-author.