As mentioned in my earlier blog (Mathematics of Origami), we have already seen how Origami goes way beyond the traditional art of paper folding, and here, we will be looking into one such application of Origami - Robots!
Robotics, being a multidisciplinary science, benefits with advancements in different technologies, such as additive manufacturing, path and motion planning, advanced control system designs, among many others. Researches in these areas have been more phenomenal than ever before in the last 10 years. Since Origami Robots offer more flexibility through increased degrees of freedom, better compliance between soft and rigid structures, shape changing capabilities and better modularity, research on Origami Robots advanced rapidly in the past ten years as well.
The idea of integrating Origami and Robots goes back in 2004 when Devin Balkcom from CMU made a Robot that folds paper into Origami models, but the concept of Robots with Origami chassis was developed later.
Let us understand more about it starting with simple, easy to understand Origami robot designs and move further towards more complex assemblies. These are a set of Origami Robots developed at Singapore University of Technology and Design. They are probably the most simple, yet brilliant designs of Origami Robots.
These are nearly 40 different kinds of 'Robotic animals' made using Origami made by 98 SUTD students. Just by adding simple actuators and controllers the students have brought Origami animals to life. These toy robots help us understand the basic concept of Origami robots: making use of Origami as the body and bringing the form to function using subcomponents of a Robot - actuators, sensors, computational capabilities, among others.
Here's a three finger Origami Robot manipulator developed by Donghwa Jeong and Kiju Lee at Case Western Reserve University in Ohio. It is based on an Origami model called 'twisted structures' designed by Mihoko Tachibana.
Link to paper: https://pdfs.semanticscholar.org/12ab/f30ff37b2278539fd97aaff518a467213bf0.pdf
There are four servo motors at the top to control the center arm, and three below to control the fingers. Such a structure can pick something as fragile as an egg shell as well as hard metal balls. This displays a prime advantage of Origami robots: Seamless shift between 'hard' and 'soft' structures.
The above image shows the 'twisted tower' on which the three finger robot is based on. There are many other robot manipulators which make use of this structure. The size of these manipulators can be easily increased or decreased based due to its modular nature.
The best thing about Origami robots is that they provide the required familiarity and beauty in form without compromising on function, which is indeed a challenge for a lot of robots, especially the commercial scale ones. Take a look at this Crab walker Origami robot developed in Harvard and MIT, made using paper and 3D polystyrene taken from children's art toy Shrinky Dinks (just 20$ of total material!). At a glance, it may look like a science project. But then it comes to life.
The robot contains embedded wires which are heated up at a controlled temperature, allowing the robot to fold or unfold. Researchers envision this to democratize robots by making them accessible for everyone to use. For ex, you can 3D print such a robot and make it play with your cat! Such robots can also be used to be sent to places where it is difficult for humans to reach (ex. space exploration, underground, etc.) , since they can be folded and unfolded at will.
Speaking of using robots to reach to hard to explore places, it is important for such robots to have albeit controlled, a high level of autonomy. They should be able to do seamlessly multitask, and thanks to Origami, along with advancements in material science, we have this shape shifting Origami robot that can walk, swim or roll!
Similar to the previous crab walker robot, this one as well relies on heat to have shape shifting capability. The exoskeletons initially start out as just sheets of plastic and the robot rolls onto them. The exoskeletons wrap around the robot based on the heat applied, in the shape of different Origami designs. This means that the robot can be adapted to different designs - boat for swimming, crawler for walking, or wheels for rolling and gliding, among others. Now isn't that absolutely fascinating research?
“In the future, we imagine robots like this could become mini surgeons, squished into a pill that you swallow,” says Daniela Rus at the Massachusetts Institute of Technology.
As we know, tasks mentioned above such as space exploration, surgery, etc. aren't performed by a single human. There is a group of highly qualified scientists and doctors doing these tasks. Enter - "Swarm Robots". A group of robots that perform tasks in coordination.
This sheet of paper contains four robots which rip themselves apart and self fold into 3D robots which can perform tasks in synchronization with each other! Need more robots? Have bigger sheet! The sheet consists of six automatically laser machined layers: A pre-stretched polystyrene, or PSPS, layer (a kind of shape-memory polymer) in the center, sandwiched between layers of copper circuits etched into polyimide sheets, with paper substrates for support. When PSPS is heated above 100° C (which can be done by running a 2.5-ampere current through the copper circuitry), it shrinks, which is what powers the robots’ self-folding behaviors. Although these robots have their own limitations (less battery life, difficult printing process, among others), researchers are working on ways to make it feasible to print sheets and sheets of these robots and get them to do tasks at our will!
The only thing that limits Origami Robots is - imagination! Now who would have thought, that Origami robots can be made using meat, to be injected inside our body?! Well, researchers at MIT, the University of Sheffield, and the Tokyo Institute of Technology demonstrated this Origami robot, which can be swallowed in the form of a pill.
It goes inside your body, unfolds itself from the pill and can patch wounds, or remove swallowed buttons! The robot movement, which is done using stick slip motion is controlled externally, through magnetic fields. Now this is indeed one of the most convincing applications of Origami Robots!
As mentioned before, the advancements in Origami Robots has increased manifold over the past 10 years and it is difficult to mention all of them here. So here's an overview of different Origami robots made till 2018. They are presented in the paper titled "Design, fabrication and control of origami robots" by Daniela Rus and Michael T. Tolley.
Inchworm-inspired crawling robot (part a), Programmable universal sheet (part b), quadrupedal microrobot (part c), myriapod-inspired microrobot (part d), transformable metamaterial (part e), self-folding swarm robot (part f), self-assembling pop-up stick-slip locomotion robot (part g), distributed pneumatic actuation of folds (part h), print and fold mobile manipulator (part i), manipulator based on twisted-tower origami pattern (part j), low-profile robotic origami with integrated sensing (part k), foldable hexapedal robot (part l), monolithically fabricated pop-up flying insect robot and support structure (part m), print and fold wheeled robot (part n), pneumatically actuated paper–elastomer composite (part o) and crawling robot driven by multistable origami (part p).
Origami robots are a prime example of what we can achieve when we explore the intersections of art and science.
The usual norm goes on to dictate that people usually have one dominant trait - left brain or right brain! But as the meme quote goes, "What if we used 100% of our brains?" :-)