Design and Fabrication Workflow for Vertebrate Soft Robots

In nature, muscles and soft skin surround bones, providing the optimal structural properties for locomotion and grasping. Despite growing interest in such hybrid hard-soft robotic systems, current design and fabrication methods require time-intensive designs and extensive simulations, hindering rapid prototyping for diverse applications. To address these shortfalls, this study presents a procedural workflow to fabricate Vertebrate Soft Robots (VSoRos) utilizing multiple materials that mimic biological tissue, cartilage, and skeletons. The proposed study combines parametric tools to customize VSoRo designs and create sequential machine instructions for multi-material fabrication. This tailored fabrication of flexible skeletal structures encapsulated in soft skins offers complementary properties such as the internal skeleton, which gives the structure the rigidity it needs to transfer force, and the skins protect the internal bones and tendons by being naturally flexible and keeping the structure together. This work fabricated monolithic flexible skeletons via fused filament fabrication (FFF) and soft silicone skins via direct ink writing (DIW). This workflow aids in the rapid design and prototyping of vertebrate soft robots, reducing the overall development time compared to conventional methods. The design and fabrication of a hybrid gripper and a lizard-like robot, along with various actuation methods, such as tendon-driven and pneumatic actuation, were demonstrated to showcase the possibilities. This proposed workflow allows researchers and roboticists to explore vertebrate-inspired designs rapidly.