Page 37 - Flexible Robotics in Medicine

20 Chapter 2

tear and may require maintenance and replacement at different times. The lack of such
components allows soft robots to achieve more continuous movement with more uniform
force distribution [1]. Soft robots often exhibit biomimicry, as it is common to take
inspiration from nature, where robotic designs are inspired from the structures and
mechanisms of plants or animals. Among cylindrical robots, many designs are mimicking
inchworms or snakes.

This project aims to extend previous work on an existing inchworm robot prototype by
characterizing the design and further developing its functionality. The project explores the
materials, geometric design, and the actuation methods of the prototype.
This project will look into fabricating a synthetic version of the body part that the robot can
travel through due to limited resources in attaining cadavers or clinical trials, similar to the
tests performed in Refs. [2,3].
An advantage of the current prototype design is its ability to fold into a sufficiently
compact, digestible size. unlike more complicated soft robot designs. This project aims to
incorporate origami elements to expand the digestibility and locomotion capability of the
current soft robot design. In addition to conventional locomotion capabilities in cylindrical
soft robot designs such as the inchworm and caterpillar locomotion, this project also
explores snake locomotion, which offers more degrees of freedom.

2.2 Literature review

2.2.1 Soft robots and origami

Origami is an instrumental design methodology that is currently contributing to the growing
field of oribotics (origami and robotics). Oribotics utilize precise creasing patterns to
achieve actuated changes between flat and folded states. Hence there are many possible
applications for origami in robot designs [4]. Basic folding designs can generate different
types of forces, depending on the tessellation of the folding patterns. Specifically, various
origami patterns demonstrate cylindrical compression, transverse planar compression,
conical compression, rotational twist compression of the cylinder, and torsional
compression of the plane [5].

For soft cylindrical robots, which can steer catheters or endoscopic devices, directional
control is an essential area of research. One recent study developed an omnidirectional
cylindrical actuator as a steerable catheter [2]. Their work is comprehensive and
utilizes six layers of various materials to achieve the omnidirectionality feature of the
actuator, with its key advantage being zero power consumption while retaining its
deformed state.