Deployable Robotic Structures via Passive Rigidity on A Soft, Growing Robot

Abstract

Deployable and reconfigurable structures use shape-changing designs to transform between different forms and create usable structures, often from small initial packages. While these structures create reliable transformations, the exact shapes must be defined at design and manufacturing time. However, many applications in unstructured environments would benefit from deployable structures that can adjust to the circumstances of the application on demand. To address this need for autonomous behavior, we propose deployable robotic structures, combining soft shape-changing robots with passive and permanent stiffening. The specific implementation in this paper uses chemical curing capable of creating stiffness change at arbitrary locations along a soft growing robot without impeding the function of the robot or requiring a continuous supply of energy to maintain its rigidity. In structural testing, the application of this method is able to drastically increase load resistances axially by an average of 64 N and transversely by an average of 2.18 Nm. Finally, two demonstrations are performed, which show how this combination of soft growing robot and permanent stiffening can increase the structure's carrying capacity and expand the robot's navigational capabilities, showing the potential of deployable robotic structures.