Imagine a robot free of rigid physical constraints. A robot that does not look like a robotic arm or a skeleton structure. What kind of shape would it take? How would it function? What purpose could it serve? These are the questions being addressed by researchers Yiğit Mengüç, Nikolaus Correll, Rebecca Kramer, and Jamie Paik. Their paper “Will Robots be Bodies with Brains or Brains with Bodies?,” recently published in Science Robotics magazine, looks to answer these questions. Their perspective is that robots can be more than machines that just run code or software bots interacting via physical instruments, but rather that any matter can be embedded with intelligence.
The Octobot, an example of soft material robots, moves on its own by turning hydrogen peroxide into gas. (Courtesy of Engadget)
Material robotics is the study of creating composite materials or integrating complex materials that are capable of combining sensing, actuation, computation, and communication capabilities, which can operate independently of a central processing unit. Researchers in this field take inspiration from nature and cite certain animals’ ability to camouflage like a cuttlefish, a bird’s ability to morph its wings during flight, or the banyan tree’s ability to grow roots above ground to support new branches as examples. In the paper, the authors write how “material robotics represents an acknowledgment that materials can absorb some of the challenges of acting and reacting to an uncertain world.”
According to Assistant Professor Mengüç from Oregon State Univ., material robotics provides us the ability to turn robots out of any material. “The future we’re dreaming of is one of material-enabled robotics, something akin to robots themselves being integrated into day-to-day objects,” says Mengüç.
A future example of this technology would be embedding technology into the rubber of your shoes. Sensors built into your shoes can support your gait and change stiffness as you run or walk based on the surface or the biomechanics of your foot. This represents an example of building complex functionality from systems of simple materials.
The biodegradable pneumatic-actuator robotic fingers like those shown here are made from gelatin and water. (Courtesy of EPFL)
The authors of the paper note that currently only two distinct approaches exist for creating complex composite materials: synthesizing new materials and system-level integration of different material components. Material scientists are currently working to develop new materials that are inherently multifunctional for robot applications. Concurrently, roboticists are working on new material systems that are composed of tightly integrated components.
The two-pronged approaches will result in the fast development of advanced material robots. Embedding distributed sensors and actuators directly into the material used in the robot’s construction creates new computational capabilities while easing the rigid information and computation requirements from its central processing system. Materials that have distributed sensing will be able to shuttle large amounts of control and feedback data.
Using biocompatible conductors or biodegradable elastomers is fundamental to material robotics. In the future, further material developments will distribute the decision-making in advanced robots.
A prototype model of a soft octopus-like robot is manufactured in layers built up during a 3D-printing process. Integrated systems animate its movements. (Courtesy of Yigit Mengüç /American Scientist)
A practical test example is the soft octopus robot being developed by Mengüç and his colleagues. The octopus serves as a perfect example of what soft robots strive to emulate. The muscle makes for an ideal actuator and the tissue is an exquisite transducer, turning energy directly into mechanical motion and is self-assembling and self-healing.
The octopus robot is pressurized with fluid and controlled with valves made by inflating two micro-channels placed in contact with each other in order of the expansion, so that the first channel closes off the second. The time delay between pressurizing the first and shutting the second was used to make the octopus robot raise and lower its arms. Such soft robotics will create a new possibility for robots to be more flexible and powerful in the future.