This Robotic Inchworm Just Made It to Higher Ground

It can now go from crawling horizontally to climbing vertically

2 min read
4 photos in a grid show a red and pink inchworm shaped robot move towards and then up a wall

The robot's gait sequence from crawling on the ground to climbing on the vertical wall

Shanghai Jiao Tong University

This article is part of our exclusive IEEE Journal Watch series in partnership with IEEE Xplore.

Each “step” for an inchworm may be small, but the diversity of terrains and orientations that these critters can crawl over is vast. They are able to inch their way across both horizontal and vertical surfaces, and use their great dexterity to navigate over uneven terrain. For these reasons, many researchershave soughtover the yearsto create robots inspired by the inchworm.

Guoying Gu is a professor at the Robotics Institute, School of Mechanical Engineering, at Shanghai Jiao Tong University, who recognizes a number of benefits of such robots. “However, most of existing inchworm-inspired soft robots have limited and specified working environments,” he says. “Especially, [the ability to] transition between horizontal and vertical planes has remained elusive.”

But, Gu and his colleagues have made significant headway on developing such a versatile robot, which they describe in a study recently published in IEEE Transactions on Robotics.

Notably, transitioning between horizontal and vertical planes is difficult for soft robots because they must be both strong and flexible—enough so to lift a foot from the ground and reach a foothold on the vertical wall or surface.

To allow more flexibility, Gu's team endowed their robot with three fiber-reinforced pneumatic actuators, which help give precise control over the “tail,” head” and “body” of the robot. A control system monitors the positioning of the actuators, and provides a coordinated movement across the robot’s whole body, allowing it to achieve the “Ω” shape of an inch worm as it crawls.

As well, the design includes two pressure suckers that have a double layer of silicone. Air between the layers can be pumped out, causing the suckers to become stiffer and more capable of dealing with higher amounts of external force and torque when suctioned to challenging surfaces.

The pneumatic actuators and suckers work together synchronously propel to the robotic inchworm forward. Just like a real inchworm, the robot extends its body, attaches its front foot (aka pressure sucker), and contracts its body before suctioning its back foot and taking another step forward. It can achieve a top speed of 21 mm/s on horizontal planes and 15 mm/s on vertical walls. In terms of loads, the robot is capable of carrying 500 grams (about 15 times its own weight) on horizontal planes, or 20 g on vertical walls.

“It is the first time to achieve transition locomotion of a soft mobile robot between horizontal and vertical planes, which may expand the workspace of the soft robot,” says Gu, noting that the robot could be useful for tasks such as inspection, cleaning, maintenance, and surveillance. The researchers also note that this design could be adapted for water, if the muscles were hydraulically actuated.

“[Our] next steps include implementing more sensors to further automate the control of the robot, reduce the size of the actuation system to make the robot untethered, and explore the possibility for our soft robot to move in more complicated environments, like on the ceiling and in unstructured territories,” says Gu.

The Conversation (0)
Illustration showing an astronaut performing mechanical repairs to a satellite uses two extra mechanical arms that project from a backpack.

Extra limbs, controlled by wearable electrode patches that read and interpret neural signals from the user, could have innumerable uses, such as assisting on spacewalk missions to repair satellites.

Chris Philpot

What could you do with an extra limb? Consider a surgeon performing a delicate operation, one that needs her expertise and steady hands—all three of them. As her two biological hands manipulate surgical instruments, a third robotic limb that’s attached to her torso plays a supporting role. Or picture a construction worker who is thankful for his extra robotic hand as it braces the heavy beam he’s fastening into place with his other two hands. Imagine wearing an exoskeleton that would let you handle multiple objects simultaneously, like Spiderman’s Dr. Octopus. Or contemplate the out-there music a composer could write for a pianist who has 12 fingers to spread across the keyboard.

Such scenarios may seem like science fiction, but recent progress in robotics and neuroscience makes extra robotic limbs conceivable with today’s technology. Our research groups at Imperial College London and the University of Freiburg, in Germany, together with partners in the European project NIMA, are now working to figure out whether such augmentation can be realized in practice to extend human abilities. The main questions we’re tackling involve both neuroscience and neurotechnology: Is the human brain capable of controlling additional body parts as effectively as it controls biological parts? And if so, what neural signals can be used for this control?

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