On-Demand Branching Mechanism Using Heat Cutting for Soft Inflatable Growing Robot

Soft growing robots are a new type of soft mobile robots that can move in environments that are challenging for conventional wheeled robots and interact with the surrounding environment. The bodies of existing soft growing robots are constructed from one tube without branches, which limits their movement and interaction capability in an environment. However, adding branches would allow the robots to explore multiple areas simultaneously while also providing support. Therefore, a novel mechanism that creates branches on demand on a soft growing robot body is proposed in this letter. This mechanism uses heat cutting to create a hole in the trunk tube to allow branch tubes to pass through the trunk. Further, we developed a branching model to estimate the time required under different inner pressure values and with different diameter branch tubes. The experimental results agreed with the proposed branching model, and we confirmed that the time for branching can be estimated from the model. We also demonstrated that the proposed mechanism could create a branch anywhere on the trunk tube using the carrying mechanism that moves on the tube. We believe that this branching mechanism can be used with various soft growing robots to enhance their operation.