Three-dimensional auxetic structure design methods based on bulking-induced deformation and the application in soft crawling robot

The 3D auxetic buckling pattern in the compression process is used to design auxetic structures. However, obtaining this pattern is time consuming and unintentional. In this paper, three auxetic structures, namely, globally deformed cross-frustum (GC) structure, partially deformed cross-frustum (PC) structure, and core deformed cross-frustum (CC) structure are proposed on the basis of the 3D auxetic deformation equation. The GC structure and PC structure can stably realize the 3D auxetic property through finite element analysis and experimental verification of structures. The structural strength of the latter structure is 2–5 times greater than that of the former structure. The CC structure exhibits a 3D auxetic property during the entire compression process and has excellent structural strength, which is greater than that of the first two structures. The rotational pattern can be also realized by the CC structure within the specified parameter range. A soft crawling robot with a motion module and perception module is designed by using the proposed auxetic structures. The motion module of the soft robot is designed by using the GC structure, and the perception module is realized by using the CC structure. The combination of modules can realize different functions, including advancement and rotation. The robot can be rapidly fabricated by digital light processing and has potential application value in medical treatment and other fields.