Design of soft robotic manipulators inspired by the elephant trunk

In this dissertation, I present my works related to the development of a soft continuum robotic arm inspired by the elephant's trunk. Firstly, the field of soft robotics is introduced together with the two scientific paradigms that relate natural models to innovative technologies: bioinspiration and biomimicry. In this context, the state of the art of robotic manipulators inspired by natural continuous arms is analyzed. I then illustrate the first technological milestone that we achieved, that is, the development of an innovative class of pneumatic artificial muscles, which we named GRACE. The GRACEs have been purposely designed to be implemented as basic actuation units in the bioinspired robotic arm, with the aim of replicating the architectures of the different muscle groups of the proboscis. Starting from the single actuation unit, we have then developed hierarchical systems of GRACEs, exploring multiple strategies to arrange them to mimic some typical muscular architectures and replicate their peculiarities. Supported by the results from mechanical characterizations, we show how adopting systems of actuators as artificial muscles improves performance differentiation and enables the implementation of bioinspired regulating methods based on fiber recruitment. The last work is focused on the designing and manufacturing of the artificial muscle groups composing the first prototypes of the elephant trunk-inspired robotic arm. The dissertation concludes with early tests on the proximal section of the trunk prototype showing how the biomimetic arrangement of the actuators involved enables contraction, elongation, and bending similar to the proboscis behavior.