A Six Degrees-of-Freedom Soft Robotic Joint With Tilt-Arranged Origami Actuator

Abstract Soft manipulators attract increasing interest in robotic applications involving the unstructured environment and human-robot interaction. The majority of the soft manipulator with fluidic actuators consists of joints that are constructed by parallel actuators, achieving rotation and extension. The inability to output twisting and lateral translations concurrently in the joints hinders the applications of such soft manipulators that require dexterous manipulation. In this work, the tilted actuator soft robotic (TASR) joint with 6DOF mobility, i.e., three rotations and three translations, is studied by kinematic modeling, simulations, and experiments. The 6DOF joint has a lightweight (74.8 g) due to the implementation of soft origami actuators (SOA) and soft-rigid structure. The investigation on the characteristics of the 4-joint assembly recorded maximum in-plane translations over a 70 mm range (70% of its diameter), axial translation over 50 mm (27% of its length), and rotations over 120 deg in all three directions. Kinematic modeling and FEM simulations have been carried out on the mechanical behaviors of the joint. A soft manipulator has been produced to verify the practicality of the joint in constructing the soft robotic systems, with the repetitive accuracy and movements demonstrated in an application scenario. The 6DOF TASR joint showed the potential to be implemented in constructing dexterous and lightweight soft robotic systems, with mass-production readiness.