The soft continuum robots are the miniturised STIFF-FLOP manipulators, which are devised for minimally invasive surgery and made of a highly deformable elastomer with a fluidic-driven principle. The robot has individually reinforced circular chambers. Braided in-extensible threads constrain the radial inflation while allowing longitudinal expansion under pressurisation. In this way, the pressurisation does not change the shape and perimeter of all actuation chambers and the strain in the circumferential direction of the reinforcement layer is negligible.
Here, we are demonstrating to use the FlowIO device to actuate such small-scale fibre-reinforced continuum robots, to further develop a portable robotic system for medical applications.
Fabrication process of the robot
(a) Moulds assembly: One set of chamber moulds is comprised of an inner core and two identical slide parts. In-extensible thread is manually wound around the assembled chamber moulds before assembling all moulds.
(b) Silicone curing: after pouring the silicone (EcoFlex 0050, Smooth On) into the moulds, the assembled chamber moulds are slid out once the silicone completely cures. In this way, the thread is partially embedded in the body of the robot. A thinner chamber mould is then inserted and cast into the inner side of the chamber, which fully integrates the thread into the silicone body. The next step is to seal the bottom and top of the robot using a harder silicone (DragonSkin 0030, Smooth On). Finally, the pneumatic pipes can be connected to the chambers via reserved holes.
(c) Demoulding and finalising the robot: The last step is to attach connection plates to the fully demoulded robot.
More details are reported in this paper：
J. Shi, W. Gaozhang and H. A. Wurdemann, "Design and Characterisation of Cross-sectional Geometries for Soft Robotic Manipulators with Fibre-reinforced Chambers," 2022 IEEE 5th International Conference on Soft Robotics (RoboSoft), Edinburgh, United Kingdom, 2022, pp. 125-131. [video]