Soft robot can easily climb loops and curves

The soft robot is composed of several parts, which can be folded into a flat disk and extended into a cylinder. Photo source: Princeton University

Engineers from Princeton University and North Carolina State University in the United States combined ancient origami technology with modern material science to create a soft robot that can easily go through a maze. In an article published in the latest issue of the journal Proceedings of the National Academy of Sciences, researchers described the process of creating robots with modular cylindrical parts.

The steering of soft robot has always been challenging, because the traditional steering equipment will increase the rigidity of the robot and reduce its flexibility. In this new design, the steering system is directly built into the robot body to overcome these problems. The concept of modular software robots also enables people to further understand the robots that can grow, repair and develop new functions in the future.

The newly created robot has the ability to assemble and disassemble in the moving process, which enables it to work as a single robot or as a group. Each part of it is an independent unit, which can communicate with each other and be assembled according to commands, or can be easily separated and connected with magnets.

The researchers built the robot from a cylindrical part in the form of origami called the Creslin pattern. This pattern allows each clip to be twisted into a flat disk and expanded back into a cylinder. This twisting and stretching movement is the basis of the robot's ability to crawl and change direction. By folding a part of the cylinder, the robot can also change direction as it moves forward.

The most challenging aspect of this work is to develop a mechanism to drive and manipulate the bending and folding motion of the robot. The researchers used two materials that react differently when heated: liquid crystal elastomer (shrinks when heated) and polyimide (expands when heated), and combined them into thin strips along the creases of the Creslin pattern. Each fold is installed with a silver Nanowire Made of stretchable heater. The current heating control strip on the nanowire heater makes the two materials deform due to different thermal expansion coefficients, which leads to folding. By adjusting the current and control strip, researchers can accurately control folding and bending, and drive the robot to move and turn accurately.