Crimped braided sleeves for soft, actuating arm in robotic abdominal surgery

Abstract

Background: This paper investigates different types of crimped, braided sleeve used for a soft arm for robotic abdominal surgery, with the sleeve required to contain balloon expansion in the pneumatically actuating arm while it follows the required bending, elongation and diameter reduction of the arm.Methods: Three types of crimped, braided sleeves from PET (BraidPET) or nylon (BraidGreyNylon and BraidNylon, with different monofilament diameter) were fabricated and tested including geometrical and microstructural characterisation of the crimp and braid, mechanical tests and medical scratching tests for organ damage of domestic pigs.Results: BraidPET caused some organ damage, sliding under normal force of 2-5 N; this was attributed to the high roughness of the braid pattern, the higher friction coefficient of polyethylene terephthalate (PET) compared to nylon, and the high frequency of the crimp peaks for this sleeve. No organ damage was observed for the BraidNylon, attributed to both the lower roughness of the braid pattern and the low friction coefficient of nylon. BraidNylon also required the lowest tensile force during its elongation to similar maximum strain as that of BraidPET, translating to low power requirements. Conclusion:BraidNylon is recommended for the crimped sleeve of the arm designed for robotic abdominal surgery.

Finite Element Analysis and Design Optimization of a Pneumatically Actuating Silicone Module for Robotic Surgery Applications

“…S oft robotics is a new field of robotic engineering 1,2 that furthers the design of flexible robots consisting of an actuating chain of multiple stiff nodes. 3 Soft robots have the potential to be used in surgical applications, 2,4,5 as the fluidlike flexibility and soft materials of these robots offer them the advantage of being able to navigate through narrow passages between organs with minimum harm to the organ soft tissue, covering outer membrane and vascular blood supply. Elastomer-based robotics have shown great promise in developing robots that mimic the muscular hydrostatic systems found in nature 6,7 such as the octopus tentacles, 8,9 caterpillars, 10 jelly fish and asteroids, 11 and elephant trunk.…”

Skins and Sleeves for Soft Robotics: Inspiration from Nature and Architecture

“…The sleeve was either a crimped plastic shell or a crimped tubular braid made from PET or nylon tows. [17,18] Such crimped braided sleeve constrains the ballooning effect and maintains constant curvature in the one-degree of freedom bending, as is demonstrated in Figure 2(b). However, such braids are rather rough running 8 the risk of causing erythema, tissue tears and bleeding [17] in abdominal robotic surgery.…”

“…[17,18] Such crimped braided sleeve constrains the ballooning effect and maintains constant curvature in the one-degree of freedom bending, as is demonstrated in Figure 2(b). However, such braids are rather rough running 8 the risk of causing erythema, tissue tears and bleeding [17] in abdominal robotic surgery. Finite element analysis (FEA) of the one-chamber actuation was carried out for the combined silicone module-crimped braided sleeve using hyperelastic constitutive models [19] for both silicone and crimped braid.…”

“…Taking into account the ±45 o fiber structure of the skin of gas pressure vessels made from composite materials in engineering and drawing inspiration from the helical fiber structure of the skin underlayer of octopus tentacles, similar fiber structure in the skin of soft pneumatically actuating modules smoothed the ballooning effect. Combining such ±45 o oriented compliant fiber structures with restricting circumferentially embroidered fibers further 17 restricted the ballooning effect, increased elongation and bending, and further stiffened the actuated module. Finally, a combination of three different types of silicone materials of different softness, with the stiffer silicone used as an internal corrugated sheet under the soft module surface seems to offer great flexibility and bending ability with minimum ballooning while it presents a smooth external module surface in possible contact with the external environment.…”

Tuneable Stiffness Design of Soft Continuum Manipulator

“…This is primarily driven by the need for a robot that can manoeuver in confined spaces and interact with organs and tissue safely, especially, in applications such as minimally invasive surgery (MIS). Numerous research studies have been conducted that demonstrate soft continuum robots for MIS applications [1,2,3,4]. The highly articulated soft robot manipulators are advantageous compared with rigid manipulators because of their low modulus, making them compliant to compressive forces and hence, allowing to manoeuvre easily and safely through narrow orifices and tight passages between organs.…”