STIFF-FLOP surgical manipulator: Mechanical design and experimental characterization of the single module

Abstract

This paper presents the concept design, the fabrication and the experimental characterization of a unit of a modular manipulator for minimal access surgery. Traditional surgical manipulators are usually based on metallic steerable needles, tendon driven mechanisms or articulated motorized links. In this work the main idea is to combine flexible fluidic actuators enabling omnidirectional bending and elongation capability and the granular jamming phenomenon to implement a selective stiffness changing. The proposed manipulator is based on a series of identical modules, each one consisting of a silicone tube with pneumatic chambers for allowing 3D motion and one central channel for the implementation of the granular jamming phenomenon for stiffening. The silicone is covered by a novel bellows-shaped braided structure maximizing the bending still limiting lateral expansion. In this paper one single module is tested in terms of bending range, elongation capability, generated forces and stiffness changing

Design, fabrication and control of soft robots

“…Embedded heaters can thus be used to adjust the structure's effective stiffness and allow for compliant behavior or actuated repositioning. Similarly, isothermal phase change caused by particle jamming has also been explored as a method of adjusting a soft robot's rigidity for actuation 42,43 ( Fig. 1f), or even for grasping an impressive array of objects 44 ( Fig.…”

On Intrinsic Safety of Soft Robots

“…Pneumatic actuators often tend to have a ballooning effect, which is fundamental for actuation. Being enveloped in a covering, the ballooning is usually not directly exposed to the workspace (Cianchetti et al, 2013), but it may not always be possible to shield the ballooning area from the work environment. If in direct contact with humans, a tear could cause sudden release of the elastic energy stored in the material, thrusting it to a nearby object.…”

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

“…Textiles including braided, knitted, or woven architectures have long been in use in medical applications of orthopaedic casts [11], soft tissue grafts such as vascular grafts [12], or ligament grafts [13]. However, although sleeves of Dacron ® crimped ,vascular grafts may restrict balloon expansion and allow bending of an elastomeric pneumatic actuator, they would not comply with an additional requirement of our current project (STIFF-FLOP), to allow for elongation and contraction of the actuating arm to be able to squeeze through narrow passages [14]. Hence, a braided bellow-type of sleeve was proposed in the STIFF-FLOP project, operating as in Figure 1(c).…”