Page 86 - Flexible Robotics in Medicine

70 Chapter 3

We have configured diamond-shaped perforations to end prematurely toward one of the
ends. This will provide increased constriction toward that end and the bending will be
much less compared to the alternative wherein the perforation promotes bending. This
variation in constriction by varying the perforation position, size, and density can be
customized depending on the need. In the prototype, we wanted to isolate the bending to
the effector region.

The prototype is made via 3D printing with Stratasys Objet260 Connex 3D printer using a
mixture of VeroClear and Tango family as the deposition material. At a ratio of 95%
VeroClear and 5% Tango black, its mechanical properties are similar to the medical-grade
polyurethane of Abbott Nutrition FLEXIFLO 12Fr Nasogastric Tube 0474.00101.

The dimensions of the perforations depend on the requirements of the design. The
considerations included limited anatomical working space; thus the functional bending
length was determined to be 50 mm. We split this into two regions due to limitations of the
control region lacking automation capabilities. The front portion would be capable of
frontal extension and contraction via singular cable tension. The second portion would be as
utilizing 4 cables for 2 DOF rotation.
The novelty deviates from currently available designs in terms of use, and specifically, the
manipulation would be perforations that confer advantages to longitudinal extension and
contraction. In general, it would adopt a diamond shape with greater transverse length than
longitudinal and the resulting bending kinematics can be described similar to the truss
structure of a stent. There is negligible bending in the plane, but compression and
extensions are extended such that series collections of said compressions and extensions of
the perforations can cumulate into a bending orthogonal to the plane of the perforation. The
native extension and compression will allow the additional DOF to extend and contract in
the longitudinal axis.

3.6.2 Search strategy

Relevant patents considered were mainly from WIPO and USPTO database. Search engines
include Google and Patsnap. The following general search strategy (Table 3.15) was
employed to sieve out the most relevant patents.
All relevant patents are reclassified into (1) bending mechanism, (2) deflection control
mechanism, (3) general endoscopic technology, and (4) portability embodiment. The focus
is on the bending mechanism applied into a home-based nanoscopic system, and hence
while the prototype may utilize technological innovation from (2), (3), and (4), our focus
in the evaluation will be on (1). As the point of prototype bench testing stage, the
prototype will be verified for its bending and insertion capabilities; hence the patent
analysis will pertain to only the utility of innovations inflexibility in bending. Selected