Prof. Kyu-Jin Cho’s Team from Seoul National University<?xml:namespace prefix = "o" ns = "urn:schemas-microsoft-com:office:office" />

 

Builds ‘Inspector Gadget Robot Arm’

 

- Published on the Cover of Science Robotics



▲ Prof. Kyu-Jin Cho, Dept. of Mechanical and Aerospace Engineering, SNU

 

On March 14, 2018, Seoul National University’s College of Engineering (Dean: Kookheon Char) announced that Professor Kyu-Jin Cho(45)’s research team from Department of Mechanical and Aerospace Engineering has developed an origami-inspired drone robot arm. The study was published on the cover of the newest issue of Science Robotics.

 

Prof. Cho’s team (first authors: Suk-Jun Kim & Dae-Young Lee; co-author: Prof. Gwang-Pil Jung of Department of Mechanical and Automotive Engineering, Seoul National University of Science and Technology; corresponding author: Prof. Kyu-Jin Cho, designer: Jeong Ryul Song) applied the ‘Variable Stiffness Mechanism’ to the robot arm with lockers and designed it to be foldable with a single line of wire, effectively improving the practicality of origami-inspired designs.

 

The folded robot is light and thin, but it stiffens instantly when unfolded, similar to an automatic umbrella. Until now, origami robots were unable to withstand their own weight and difficult to operate due to their lack of structural stiffness. This study offers a solution that can overcome such restraints.

Variable Stiffness Mechanism was inspired by an origami principle of two perpendicular fold lines constricting each other. Using this mechanism, a box-like structure (40×40×100mm) lighter than 30g can withstand the compression force of 12kg. It can be folded flat by pulling the wire to unfasten the lockers.

 

In the video, the drone unfolds its arm to pick up an object inside a narrow ditch, taking close-up videos as it moves between tree branches. When it is not in use, the robot can be folded to be compact and portable. This demonstrates an innovative method that deals with two major limitations of robots: weight and space. Especially for drones, which are the most limited, a foldable robot arm offers numerous advantages. The research can be applied to robots and structures other than drones, and used in extreme environments such as deserts, ocean, and outer space.

 

Prof. Cho explained that “while extremely flexible in movement, soft robots couldn’t withstand strong forces. But this robot arm uses a technology called variable stiffness, which is something between a soft robot and a hard robot. It can be folded but stiffened upon use. We also used a compound material of soft fabric and specially processed PET film.”

 

Q: How can the robot arm be folded and unfolded with a single wire?
A. It’s because of internal wire paths of the arm. We designed the paths so that with one wire, you can consecutively unlock the variable stiffness mechanism then fold up the arm. Pulling the wire, you generate two forces: one that unlocks the variable stiffness mechanism and another that folds the arm. But when the lockers are in place, the force that folds the arm is offset by the lockers, leaving only the variable stiffness mechanism to be unlocked. After that, the arm is folded. This kind of wire-based mechanism can be easily expanded in scale. You can apply it to one module, and as you can see in the video, a long arm consisting of seven modules can be operated with a single wire as well. When you unwind the wire, rubber bands inside of the robot arm unfolds the module, and lockers are fastened magnetically.

About Prof. Kyu-Jin Cho

Current Director of Human-Centered SoFT Center, Prof. Cho received the RAS Early Career Award by the IEEE Robotics and Automation Society in 2014, recognized for his contributions to soft robotics and biologically inspired robot design. In 2015, he developed the ‘water strider robot,’ published in Science for the first time in College of Engineering at SNU. He received widespread attention for the ‘Exo-Glove Poly,’ a soft wearable robot which can help disabled people in performing daily tasks, presented at the American Association for Advancement of Science (AAAS) Annual Meeting in 2016. In April of the same year, the robot SNUMAX from his lab won first place at the RoboSoft Grand Challenge, held for the first time in the world in Pisa, Italy. (End of article)

▲ The drone picks up an object in a narrow ditch from afar, unfolding its origami robot arm

[Research paper]

Link: https://www.dropbox.com/sh/2eyw2mhbb9ujk99/AACM-DE7MAcUUiETaDW0VB5ua?dl=0

 

[Photo]

Link: https://www.dropbox.com/sh/otuxrc4dy1ow2lm/AADfACw3Bkkt9pmExGTcX4ypa?dl=0

 

[Video]

Link: " target="_blank" rel="noopener">

SNU Engineering News http://eng.snu.ac.kr/node/15652
Korean Economic Daily http://news.hankyung.com/article/2018031485141Dong-A Ilbo http://news.donga.com/3/08/20180316/89126628/1