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Robot Made of Clay Can Sculpt Its Own Body

This clay robot can squeeze and squish itself into different shapes

2 min read
Closeup of a person's hands holding the robot
Photo: Evan Ackerman

We’re very familiar with a wide variety of transforming robots—whether for submarines or drones, transformation is a way of making a single robot adaptable to different environments or tasks. Usually, these robots are restricted to a discrete number of configurations—perhaps two or three different forms—because of the constraints imposed by the rigid structures that robots are typically made of.

Soft robotics has the potential to change all this, with robots that don’t have fixed forms but instead can transform themselves into whatever shape will enable them to do what they need to do. At ICRA in Montreal earlier this year, researchers from Yale University demonstrated a creative approach toward a transforming robot powered by string and air, with a body made primarily out of clay. 

Image of robotPhoto: Evan Ackerman

The robot is actuated by two different kinds of “skin,” one layered on top of another. There’s a locomotion skin, made of a pattern of pneumatic bladders that can roll the robot forward or backward when the bladders are inflated sequentially. On top of that is the morphing skin, which is cable-driven, and can sculpt the underlying material into a variety of shapes, including spheres, cylinders, and dumbbells. The robot itself consists of both of those skins wrapped around a chunk of clay, with the actuators driven by offboard power and control. Here it is in action:

The Yale researchers have been experimenting with morphing robots that use foams and tensegrity structures for their bodies, but that stuff provides a “restoring force,” springing back into its original shape once the actuation stops. Clay is different because it holds whatever shape it’s formed into, making the robot more energy efficient. And if the dumbbell shape stops being useful, the morphing layer can just squeeze it back into a cylinder or a sphere.

While this robot, and the sample transformation shown in the video, are relatively simplistic, the researchers suggest some ways in which a more complex version could be used in the future:

The robot morphing skins.This robot’s morphing skin sculpts its clay body into different shapes.Photo: IEEE Xplore

Applications where morphing and locomotion might serve as complementary functions are abundant. For the example skins presented in this work, a search-and-rescue operation could use the clay as a medium to hold a payload such as sensors or transmitters. More broadly, applications include resource-limited conditions where supply chains for materiel are sparse. For example, the morphing sequence shown in Fig. 4 [above] could be used to transform from a rolling sphere to a pseudo-jointed robotic arm. With such a morphing system, it would be possible to robotically morph matter into different forms to perform different functions.

Morphing Robots Using Robotic Skins That Sculpt Clay, by Dylan S. Shah, Michelle C. Yuen, Liana G. Tilton, Ellen J. Yang, and Rebecca Kramer-Bottiglio from Yale University, was presented at ICRA 2019 in Montreal.

[ Yale Faboratory ]

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