Foldability is a useful characteristic in robotics for reaching into confined spaces. Origami-like designs, which promise efficient foldability, have previously had the difficulty of maintaining structural stiffness. Professor Kyu-Jin Cho of the Department of Medical Science and Engineering at Seoul National University (SNU) and the SNU Soft Robotics Research Center proposed a stiffening mechanism that can provide stiffness while preserving the advantages of the origami-inspired structure. The solution comes from a variable stiffness mechanism that is based on the principle of perpendicular folding.

The variable stiffness mechanism works by keeping a collapsible locker to switch between flexibility and rigidity. When inactive, the arm can be on standby in a soft state. Just by pulling a wire, the variable stiffness mechanism can be activated to convert it into a rigid state. Releasing the structure is done equally simply by pulling the wire, and in this way the structure reverts to a foldable one. The simplicity of the design allows for the proposed mechanism to be applicable to machines in harsh conditions.