This project developed a computational approach to the design and fabrication of origami robots. Origami robots are autonomous machines, whose morphology and function are created using folding. Their bodies include folds that are dynamic, contributing to the actuation capabilities of the machine. The prototypical origami robot starts as a single planar sheet that is transformed into a complex three-dimensional (3-D) morphology using folding. Origami robots have built-in compliance through the geometry of the folds and creases in the material. 

Origami robots redefine how we make and use robots.  Traditionally, robots have been complex systems consisting of many parts (e.g. rigid members, actuators, sensors, microprocessors), requiring significant human development effort and expertise in multiple disciplines to design, build, and control. Conventional fabrication of robots is a serial assembly process where the addition of design elements increases the complexity of fabricating and controlling the robot. Folding is a means of decoupling design complexity from fabrication complexity. It enables creating new 3-D structures from planar sheets that can be made from a wide range of materials (e.g. plastics, metal, paper, rice paper, sausage casing, etc.) by manipulating the planar sheet intuitively. When these techniques are leveraged for robot manufacturing, the results are fast to produce and require little manual assembly.

The outcomes of this project include advances in computational origami algorithms, materials, designs, and robot systems. A key contribution in computational origami theory describes the universality of origami as a way to design any geometric shape. Folding can also be used as a vehicle for physical change to create shape-shifting machines that take on the best shape required by the task at hand, including sheets with programmable shape and support structures that precisely assemble small devices. When designed carefully, a fold pattern can produce not just a 3-D shape, but a functional robot, one that can continue to move and transform. Our research has shown that theoretically, any mechanism is possible by using algorithms for fold pattern composition on individual designs for foldable joints, and more broadly a variety of mobile robots. These designs can be converted into practical devices using a variety of fabrication methods, for example to create Micro Aerial Vehicles, Robot Grippers, and Wheel-based Robots.

Using metamorphosis in nature as inspiration, we introduced an alternative approach to extending the capabilities of a robot by enabling it to cyclically acquire multiple self-folding origami sheets called ?exoskeletons?. Like an egg, the system commences with a cubic magnet ?robot?, called Primer. The robot hierarchically develops its morphology by combining with different exoskeletons: for example, it becomes able to move faster, to become bigger, or to employ different locomotion on ground, in water, and in the air.

Origami folding can be used to create a new class of very strong actuators we call Fluid Driven Origami Actuator Muscles (FOAMS). Artificial muscles hold promise for safe and powerful actuation for common machines and robots. However, the design, fabrication, and implementation of artificial muscles are often limited by their material costs, operating principle, scalability, and single-degree-of-freedom contractile actuation motions. We developed an architecture for fluid-driven origami-inspired artificial muscles. Experiments reveal that these muscles can contract over 90% of their initial lengths, generate stresses of approximately  600 kPa, and produce peak power densities over 2 kW/kg?all equal to, or in excess of, natural muscle.

Additionally, origami reasoning can be used to create new types of materials ? we call handed shearing auxetic materials. In nature, repeated base units produce handed structures that selectively bond to make rigid or compliant materials. Auxetic tilings are scale-independent frameworks made from repeated unit cells that expand under tension. We discovered how to produce handedness in auxetic unit cells that shear as they expand by changing the symmetries and alignments of auxetic tilings. Using the symmetry and alignment rules we developed, we made handed shearing auxetics that tile planes, cylinders and spheres. By compositing the handed shearing auxetics in a manner inspired by keratin and collagen, we produce both compliant structures that expand while twisting, and deployable structures that can rigidly lock. This work opens up new possibilities in incorporating origami into design, for example designing chemical frameworks, medical devices like stents, robotic systems, and deployable engineering structures.

Origami design and fabrication can be used as an effective education tool. To this end, this project contributed the Origami Robot Garden, a platform with over 100 robots (flowers, sheep, ducks) that can be used for teaching making and computational thinking to middle school students. The Robot Garden has been used as part of the activities for the Hour of Code.

In addition to advancing the science and engineering of creating origami machines, the project trained many undergraduate, graduate, and postdoctoral students, and contributed several outreach activities to schools through hands-on activities and to the general public through origami art.

Last Modified: 12/06/2018
Modified by: Daniela Rus