A lobster-inspired articulated shaft for minimally invasive surgery

Novel applications of soft pneumatic actuation in minimally invasive surgery (MIS) are proposed due to its relatively safe robot–environment interactions. Although the inherent compliance of soft robots makes them suitable for surgery, their low force output and complicated system response and behavior may limit their potential as practical MIS instruments. In this paper, three lobster-inspired antagonistic modules are proposed to realize bidirectional translational, bending and rotational motions and variable stiffness in centimeter scale. Their modular design enables flexible combinations of articulated shafts to satisfy end-effector workspace requirements in MIS. Theoretical models are proposed to relate the input pressure, deformation, output force/torque and stiffness, which provide quantitative solutions for independent adjustment on the deformation and stiffness of each module. A series of experimental results show that the proposed modules can deliver sufficient force and torque output for MIS applications, and they can be conveniently assembled into articulated shafts featuring safe actuation, high dexterity, stiffness tuning and reconfigurability. •Three soft-rigid antagonistic mechanisms inspired by lobster leg joint.•Designs of three miniature soft-rigid hybrid modules for different motions.•Explicit theoretical modeling that enables independent stiffness adjustment.•A modular design strategy for articulated shafts for minimally invasive surgery.