Robogamis Are the Real Heirs of Terminators and Transformers

Paper folding inspires small, versatile robots that can work together.

Technology

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September-October 2020

Volume 108, Number 5
Page 282

DOI: 10.1511/2020.108.5.282

Ask anyone what image comes to mind when you say the word “robot,” and there’s no doubt you’ll receive responses inspired by popular culture: for example, the liquid-metal, shape-shifting T-1000 from the movie Terminator 2: Judgment Day; or Optimus Prime, leader of the Autobots and the main character in the Transformers films. And who can forget Data from Star Trek: The Next Generation, a cybertronic version of Pinocchio, seeking to become more human?

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These (and countless other) examples have humanoid characteristics embedded in their designs. When Optimus isn’t a truck, he has arms and legs. The T-1000’s default form appears as a human. Data was modeled after his very human creator. By Hollywood standards, the ultimate form of robotic technology would be outwardly indistinguishable from humans themselves.

Our imaginations run free, but technological challenges still limit the creation of robots that perfectly mimic humanoid conventions in the real world. I’ve tried to rise to the task nonetheless. My studies in mechanical engineering allowed me to pursue my quest to design mechanisms with challenging parameters. One of my projects was designing a human ocular motor simulator. No, it was not a project to make a Terminator component; rather, it was an effort to understand and simulate the behavior of the human eye.

Courtesy of Zhenishbek Zhakypov, Reconfigurable Robotics Laboratory, EPFL

This project required conceiving of an ocular system that made a saccadic movement—a quick, simultaneous movement of two eyes in the same direction with a peak velocity of more than 500 degrees per second (yes, we humans do that). Like human eyes, the mechanical system would operate through three independent rotational degrees of freedom. Our eyes not only move up-down and left-right, but also exhibit torsion—twisting movements. To fit all the electrical and mechanical parts, including joints, links, and motors, in an integrated system was a challenge—and all for a very defined and singular task.

QUICK TAKE
  • Robots that mimic human form are limited by current technology, and even when systems are successfully built, they lack the capacity to adapt to different tasks and situations.
  • Instead of trying to copy humans, a more fruitful approach could be to take inspiration from origami, which uses one component and reconfigures it for many forms.
  • Robogamis are small, but they can traverse uneven terrain by rolling, flipping, or jumping, and they can work in teams or link up to accomplish more complicated tasks.

A few other types of humanoid- inspired robots followed. And although I succeeded in satisfying the immediate goal, whatever it was, my robots had limitations. For example, I designed a robotic hand with eight degrees of freedom attached to a robotic arm with seven degrees of freedom; together they weighed 3.7 kilograms (about as much as a human arm and hand). This upper extremity was flexible enough to grab and throw a baseball, but it could not pick up a coin. It could shake hands with a strong grip but wasn’t able to play a thumb war.

Origami has for ages taken the same basic component and used it to create many distinct forms—a goal of microrobotics.

The limbs I was creating were, in short, limited in function. They had a fixed number of joints and actuators, which meant that their functionality and shape were constrained from the moment of their conception. Think about that robotic hand: It had articulated and motorized joints that allowed it to hit a ball, but it was not suited to make scrambled eggs. But if there were an infinite variety of tasks, would it require an infinite variety of combinations?

Limitless microbots seen in movies such as Big Hero 6 seemed far away. But then I realized that a flexible and versatile design platform already existed. This method of taking the same basic component and using it to create many distinct and specific forms has been done for ages. It’s called origami.

Fold and Refold

Who hasn’t made a model plane, boat, or crane out of one sheet of paper? Origami is an already existing and highly versatile platform for designers. From a single sheet, you can make multiple shapes, and if you don’t like the result, you unfold and fold back again. Indeed, mathematics has proven that any three-dimensional form can be made from the folding of one or more two-dimensional surfaces.

Courtesy of Zhenishbek Zhakypov, Reconfigurable Robotics Laboratory, EPFL

Could this be applied to robotic design? Imagine a robotic module that would use polygon shapes to construct multiple different forms to create many robots for many different tasks. Furthermore, picture having an intelligent sheet that could self-fold into any form it wants, depending on the needs of the environment.

I made my first origami robot, which I called a “robogami,” about 10 years ago. It was a simple being, a flat-sheeted robot that could turn into a pyramid and back into a flat sheet, and then into a space shuttle.

My research, conducted with the help of PhD students and postdoctoral researchers, has advanced since then, and a new robogami generation is now seeing the light of day. This new generation of robogamis serves a purpose: For example, one of them can navigate through different terrains autonomously. On dry and flat land, it can crawl. If it suddenly meets rough terrain, it will start to roll, activating a different sequence of actuators. Furthermore, if it meets an obstacle, it will simply jump over it. It does this by storing energy in each of its legs, then releasing it and catapulting itself like a slingshot.

Courtesy of Zhenishbek Zhakypov, Reconfigurable Robotics Laboratory, EPFL

The robogamis could even attach and detach, depending on the environment and task. Instead of being a single robot that is specifically made for one single task, robogamis are designed and optimized to multitask from scratch.

Courtesy of Zhenishbek Zhakypov, Reconfigurable Robotics Laboratory, EPFL

This is an example of a single robogami. But imagine what many robogamis could do. They could join forces to tackle more complex tasks. Each module can either actively assemble or passively be assembled to create different shapes. And not only that, by controlling the folding joints, they can attack diverse tasks in changing environments. For example, think about outer space, where the conditions are unpredictable. A single robotic platform that can transform to do multiple tasks could increase the mission’s probability of success.

Building 3D from 2D

Robogami design owes its drastic geometric reconfigurability to two main scientific breakthroughs. One is its layer-by-layer 2D manufacturing process: Multiples of functional layers of the essential robotic components (such as microcontrollers, sensors, actuators, circuits, and even batteries) are stacked on top of one another. The other is the design translation of typical mechanical linkages into a variety of folding joints (such as fixed joint, pin joint, planar joint, and spherical link).

This approach means that, instead of focusing just on minimizing the size of the joint components, we can actually reduce the number of components when designing robots. We can miniaturize systems with numerous components that require complex assembly and calibrations by making them flat; they can be stacked and still maintain their precision.

Courtesy of Zhenishbek Zhakypov, Reconfigurable Robotics Laboratory, EPFL

One such system is a haptic device, whereby a user and a computer interact through a mechanism such as a joystick. These devices are conventionally used as surgical robots when surgeons require high precision with delicate force feedback. This use requires a large operating room with high degree-of-freedom robotic arms, so that surgeons can feel differences in the stiffness of organs and cavities through a motorized interface that translates the force difference at the tip of a robotic end-effector.

Instead of being a single robot that is specifically made for one single task, robogamis are designed to multitask from scratch.

With robogamis, haptic technology can be accessible in more situations than ever. A robogami haptic interface would be like a foldable joystick that could be fitted to a cell phone cover. Having a haptic interface linked directly to a cell phone would mean that it could be used as a portable joystick for our daily activities such as online learning or shopping. This setup would allow you to, say, feel the different organs in a human anatomy atlas, the different geographical features on a map, or even the hardness or ripeness of different types of cheese and peaches.

Robotics technology is advancing to be more personalized and adaptive for humans, and reconfigurable origami robots show immense promise. They could become the platform to provide the intuitive, embeddable robotic interface to meet our needs. Robots will no longer look like the characters from the movies. Instead, they will be all around us, continuously adapting their form and function—and we won’t even know it.


This article is adapted from a version that appeared in Aeon (http://aeon.co)

Bibliography

  • Mintchev, S., M. Salerno, A. Cherpillod, S. Scaduto, and J. Paik. 2019. A portable three-degrees-of-freedom force feedback origami robot for human–robot interactions. Nature Machine Intelligence 1:584–593.
  • Seo, J., J. Paik, and M. Yim. 2019. Modular reconfigurable robotics. Annual Review of Control, Robotics, and Autonomous Systems 2:63–88.
  • Sonar, H. A., A. P. Gerratt, S. P. Lacour, and J. Paik. 2019. Closed-loop haptic feedback control using a self-sensing soft pneumatic actuator skin. Soft Robotics 7:22–29.
    • Zhakypov, Z., K. Mori, K. Hosoda, and J. Paik. 2019. Designing minimal and scalable insect-inspired multi-locomotion millirobots. Nature 571:381–386.
    • Zhakypov, Z., and J. Paik. 2018. Design methodology for constructing multimaterial origami robots and machines. IEEE Transactions on Robotics 34:151–165.