MSMechanical SciencesMSMech. Sci.2191-916XCopernicus PublicationsGöttingen, Germany10.5194/ms-9-51-2018Design and evaluation of a continuum robot with extendable balloonsA continuum robot with extendable ballonsYarbasiEfe YamacSamurEvrenevren.samur@boun.edu.trhttps://orcid.org/0000-0002-4634-7611School of Aerospace Engineering, Georgia Institute of Technology, Atlanta, GA 30308, USADepartment of Mechanical Engineering, Bogazici University, Istanbul, 34342, TurkeyEvren Samur (evren.samur@boun.edu.tr)7February201891516012July201728December20179November2017This work is licensed under the Creative Commons Attribution 4.0 International License. To view a copy of this licence, visit https://creativecommons.org/licenses/by/4.0/This article is available from https://ms.copernicus.org/articles/9/51/2018/ms-9-51-2018.htmlThe full text article is available as a PDF file from https://ms.copernicus.org/articles/9/51/2018/ms-9-51-2018.pdf
This article presents the design and preliminary evaluation of a novel
continuum robot actuated by two extendable balloons. Extendable balloons are
utilized as the actuation mechanism of the robot, and they are attached to
the tip from their slack sections. These balloons can extend very much in
length without having a significant change in diameter. Employing two
balloons in an axially extendable, radially rigid flexible shaft, radial
strain becomes constricted, allowing high elongation. As inflated, the
balloons apply a force on the wall of the tip, pushing it forward. This force
enables the robot to move forward. The air is supplied to the balloons by an
air compressor and its flow rate to each balloon can be independently
controlled. Changing the air volumes differently in each balloon, when they
are radially constricted, orients the robot, allowing navigation. Elongation
and force generation capabilities and pressure data are measured for
different balloons during inflation and deflation. Afterward, the robot is
subjected to open field and maze-like environment navigation tests. The
contribution of this study is the introduction of a novel actuation mechanism
for soft robots to have extreme elongation (2000 %) in order to be
navigated in substantially long and narrow environments.
Introduction
In order to achieve a high level of precision, rigidity has
long been an optimization criterion for robot designers (Grossard et al.,
2013). This resulted in very stiff robots that consist of rigid links.
Although rigid-link robots dominate the industry, they cannot be of any help
for some cases of diagnostic, pipe inspection, or medical applications, where
a videoscope is used to access remote locations through narrow holes for
visualization. In such operations, flexibility of the manipulators would help
greatly to reach difficult-to-access sites and complete the task with high
dexterity (Rus and Tolley, 2015). The idea of designing and developing
a robot that can be easily guided through unstructured, substantially-long
and narrow environments to perform exploratory operations such as for natural
disaster relief, or pipe inspection (Majidi, 2014) was the motivation that
led to this research (see Fig. 1).
In order to achieve high maneuverability, a soft continuum-type design
(Robinson and Davies, 1999) is utilized for the target application. In such
applications, soft robots are safe to work with, since they are made of
compliant materials (Conrad and Zinn, 2015). Continuum robots generally
behave like some animal organs, called muscular-hydrostats (Kier and
Smith, 1985), even though they consist of a backbone. Since this
backbone is a deformable structure rather than a rigid spine, continuum
robots are moved via deformation of the backbone (Walker, 2013). Backbones
bend continuously along their length via elastic deformation and produce
motion by generating smooth curves (Robinson and Davies, 1999).
Theoretically, they are able to take any shape in the working environment.
Therefore, these types of robots are also named as hyper-redundant
since they have a very large number (or infinite) of active degrees of
freedom (DOF) (Chirikjian and Burdick, 1994; Kang et al., 2013). An advantage
of having a deformable low-stiffness backbone is that these types of robots
generate little resistance to compressive forces. Thus, they can conform to
obstacles (Chirikjian and Burdick, 1990). This fact also enables the robots
to work in unstructured environments, where a robot cannot rely on a detailed
and accurate model of the environment (Katz et al., 2008) and may run into
unexpected obstacles. These advantages make this class of robots well-suited
for highly dexterous tasks and tasks that include environmental uncertainty
(Katzschmann et al., 2015). With utilization of newly developed compliant
matters and fabrication techniques and utilizing these matters in continuum
robots, they can be enabled to tolerate very high strains and extreme
configurations (Laschi et al., 2016). Backbones can be axially extended by
utilizing different mechanisms, for example by actuating antagonistic tendons
that are placed about the longitudinal axis (Chirikjian and Burdick, 1994)
with the option of spring loading (Tonapi et al., 2015) or having telescopic
precurved concentric tubes along the backbone and rotating them independently
(Swaney et al., 2015). A locally actuated backbone continuum robot design is
the closest to the biological continuum structures (Walker, 2013). Backbone
of these robots is directly formed by the actuators. This type of robots may
also consist of modules, and each module can be actuated independently in
order to enable the backbone to get into the desired configuration.
A surgical instrument that consists of five successive flexible segments
utilizes McKibben actuators (Chou and Hannaford, 1996) has been presented in
the literature (Moers et al., 2012). This manipulator uses pneumatic
actuators in a parallel combination in each of its segments and controls the
position of the end effector by independently controlling McKibben actuators.
High precision can be achieved because of the stiffness of the manipulator
and high pressures in the actuators. A similar design utilizing three fiber
reinforced elastomeric enclosures in parallel combination has also been
presented (Bishop-Moser et al., 2012). Another soft manipulator has been
designed, and its deformation characteristics are analyzed in detail while
performing tasks (Marchese et al., 2015). As one might expect, an octopus arm
has been a great example of a soft, continuum-type manipulator from nature.
It has been studied in detail and a manipulator that mimics an octopus arm
has been designed (Calisti et al., 2011; Laschi et al., 2012). This robot is
operated with cables and shape memory alloy springs to achieve high
dexterity.
A robot navigating through an unstructured environment, serving
a screening procedure.
Soft robots can experience large deformations due to their compliant
structure (Laschi et al., 2016; Cianchetti et al., 2015). The typical axial
elastic strains attained in the literature are in the order of 40 %
(Follador et al., 2012), 200 % (Ranzani et al., 2015), and 300 %
(Hawkes et al., 2016). The dynamics of a modular compliant robot is
rigorously derived (Godage et al., 2016). However, navigating in
substantially long and narrow environments, or accessing remote locations
might benefit from much higher strains such as 1000 %. Even though they
are precise, modular robots fail to achieve such high strains. To the best of
our knowledge, none of the state-of-the-art designs could tolerate such high
strains when this work was completed (Yarbasi, 2016). However, a new kind of
robots, so-called vine robots, has been recently proposed which can
lengthen by thousands of percent by growth (Hawkes et al., 2017).
In this study, a soft-continuum robot with a novel actuation mechanism
is presented. The robot is of locally actuated backbone type. The
backbone composes of two extendable balloons in a parallel
configuration, and they provide the actuation by means of changing air
volumes in the balloons. In contrast to examples in the literature,
the actuators extend in length, tolerating extreme axial
strain, while their diameters stay almost constant as they are
pressurized. Apart from this advantage, the proposed design inherently
has the ability to utilize contact forces to guide itself through an
unstructured environment. This paper presents the design, prototype
development, characterization and experimental evaluation of the
proposed continuum robot prototype.
Schematic representation of the robot and the inflation
process. (a) Uninflated robot in the initial condition,
(b) inflated robot.
Navigation through obstacles is demonstrated. In region 1,
the lower balloon is inflated more in order to have a curvature to
avoid lower obstacle. A similar procedure is followed in region 2.
Conceptual design
The proposed continuum robot is composed of two balloons, a tip and
a flexible extendable sheath as illustrated in Fig. 2. The sheath is
used to keep the inflated sections of the balloons together by
constraining them in the radial direction. The sheath and the inflated
balloons form the flexible and extensible shaft of the continuum
robot. The tip, on the other hand, is a solid structure that contains
the uninflated sections of the balloons. The balloons used in this
study are called long or cylindrical balloons. They
are able to elongate much in length without having a very significant
change in diameter. The inflated sections of the balloons are
represented as the green tubes and the uninflated sections are shown
as helical structures in the tip in Fig. 2. During inflation, the
balloons start to inflate from the proximal section and the inflated
section progresses towards the distal end. While a balloon is
inflating, it will apply a force on the tip of the robot, pushing it
forward. Simple inflation is demonstrated in Fig. 2. The slack section
remaining at the distal end gradually decreases and pulled into the
shaft until the balloon is fully inflated. If multiple balloons are
used and restricted in the radial direction, only longitudinal strain
will take place. Since only two balloons are used, the robot can be
actuated to move in a two-dimensional plane by controlling the air
volumes in each balloon. Positioning their inlets in the same place,
constricting them radially in an extendable sheath and making sure
that their distal inflated sections have contact with the tip results
in a constricted continuum mechanism. This constriction enables the
robot to perform elongation, shortening and bending. Elongation and
shortening can be obtained by altering the air volumes in two balloons
at the same time. The axial elasticity of the balloons makes
shortening possible as the balloons are deflated. Bending, on the
other hand, is provided by changing the air volumes in both balloons
by different amounts. As an example, navigation through obstacles is
demonstrated in Fig. 3.
Since the robot has no rigid backbone, it can easily be guided through
obstacles. Moreover, exploiting the advantage of continuum robots, the
ability to take every configuration in the workspace, obstacles that
are already past have no effect on further navigation. This is because
the balloons expand only from the distal end. The inflated section is
constricted by obstacles and remains stationary while the tip of the
robot moves forward with the increased air volume in the pneumatic
actuator.
Cylindrical balloon model
Since the balloons, positioned in the shaft in a parallel
configuration, constitute the backbone, all motion capabilities of the
robot depend on characteristics of individual balloons. Therefore, it
is of utmost importance to understand how balloons behave under
different loading and boundary conditions. The balloons used in this
study can be modeled as a cylindrical membrane. If the length of the
cylinder is sufficiently long compared to the diameter, the force
balance on the cylindrical part will not be affected by the ends even
though an actual balloon is closed at the ends (Müller and
Strehlow, 2004). For a cylindrical element, the relation between hoop
stress σθ and axial stress σL is given by
the well-known equation σθ=2σL. Since hoop
stress is higher than axial stress, the balloon will tend to elongate
rather than expand in the radial direction. The relation between axial
stretch λ=L/L0 and hoop stretch μ=ρ/ρ0 is
approximated by:
λμ=12Kμ2-1μ22K+μ2+12Kμ2-1μ22K+μ22+Kμ-2+22K+μ2.
Also, pressure regarding the hoop stretch μ can be found as:
p(μ)2s-d0/ρ0=1λμ2λ2-1λ2μ2K+μ2,
where K is minus the ratio of elasticity coefficients
-s+/s-, ρ and ρ0 are the current and initial
radii respectively, L and L0 are current and initial lengths
and d0 is the wall thickness of the balloon (Müller and
Strehlow, 2004).
In Fig. 4, pressure pμ from Eq. (2) is plotted with
respect to µ. s+ and s- are taken as 3 and
-0.3 bar, respectively; ρ0 is 0.32 cm and
d0 is 0.025 cm. It is observed that pressure becomes
independent of hoop stretch for large values of it. Initial peak at
μ=1 occurs since the air that is first pumped in the balloon
has to overcome both radial and axial stiffnesses. It is expected that
pressure requirement will be less for maintaining the volume than for
initial inflation.
The plot of p=p(μ) for an extendable balloon.
Developed prototype and experimental setup.
Robotic system overview
Following the conceptual design explained earlier, the continuum robot
has been developed. The whole robotic system is shown in Fig. 5. Two
extendable balloons are placed in a radially constricted and axially
flexible shaft. The tip is made of polyurethane foam. The balloons
used in this study are off-the-shelf Qualatex cylindrical
balloons. A typical balloon has an uninflated initial length of
30 cm and a diameter of 4 mm. It is manufactured from
natural rubber latex. Initially, the slack section remains outside of
the tip, and the robot occupies approximately a 60 mm long
space having a diameter of 50 mm (diameter of the tip). As the
balloons are inflated, a continuous pushing force is generated at the
back of the tip. Thus, the robot moves forward, and some amount of the
slack section is ever so slightly retracted.
In order to control the air volume in the balloons the architecture
given in Fig. 6 is used. Two air pumps (Parker BTC Diaphragm) and four
two-way, normally closed solenoid valves (FG Line C1) are
utilized. Pumps are operated at 18 V and valves are at
12 V DC. Two potentiometers are utilized as the user
interface. Since the valves are able to work only on and off, valves
are operated via Pulse Width Modulation (PWM) signals for speed
control of inflation and deflation. PWM signals are generated by an
Arduino Uno board at 1024 Hz. According to the value read from
the potentiometers, each valve is assigned to one of three operating
regions: on, on/off switching or off. In the on/off switching region,
on and off times are controlled by pulse widths of PWM signals. Since
the valves are not fast enough to track every pulse, for example very
low duty cycles, their working region has been calibrated to ensure
stable operation.
Architecture used in this study.
Experimental resultsBalloon characterization
In order to characterize single balloon behavior, three experiments
were performed. We performed these experiments to find the limits of
the robot in terms of attainable maximum extension, highest speed,
inlet pressure, and output force. First, elongations of seven
individual balloons and their internal pressures were recorded while
the balloons were inflated with the valves fully open (100 % duty
cycle). Air pressures in the balloons were measured using a Setra C206
Pressure Transducer. For each balloon, elongation was recorded for
five consecutive inflations and deflations in order to determine the
differences of each balloon and inflation speeds, which will also
correspond to the same characteristics of the robot. In this
experiment, elongation is measured as the length of the inflated
section of the balloon. This length can be considered as an
effective length of the balloon since the tip is always at
the end of the inflated section. As expected from Fig. 4, pressure
peaks were observed during initial inflation. Since the change in
radii of the balloons was not significant, they were measured manually
and not tracked with a sensor. Any sensor on such a soft material
would distort the stress state.
Elongation behavior of the balloons for inflation and
deflation. The solid line represents the mean elongation for seven
balloons. The shaded area is the standard error of the mean.
Maximum elongations did not change much after second inflation. This
behavior can be explained with the plasticity of the balloons. Their
elasticities tend to converge in later inflations. During deflation,
the positions tended to decrease almost at the same time. However, at
the last stages of deflation, balloons sometimes went unstable as they
had two local equilibrium points. This stability problem resulted in
two inflated sections with a slack part in the middle. The same
procedure was carried out for seven different balloons. The mean of
last three repetitions was computed for each balloon. Then, the
overall means and the standard errors of elongation for seven balloons
were calculated. The mean values are plotted with respect to time in
Fig. 7, where the standard error is represented as the shaded
region. It was seen that the balloons expanded almost linearly. When
they were close to full extension (i.e., when there was very little or
no slack section left), their extending speed tended to decrease, and
the extension was finally converged to a value of 124±6cm. Deviation in this value can be explained by the
differences in individual structural properties of a balloon as these
local properties affect the inflation trend and the maximum length
that a balloon can extend. Considering the linear regions in the
inflation and deflation curves, average maximum speeds are about 3.8
and 21.0 cms-1, respectively.
Second, in order to demonstrate the effects of different pulse widths
on inflation behavior (i.e., inflation speed and pressure), a balloon
was inflated with three different PWM signals; 33, 66 and 100 %
duty cycles of the solenoid valves. These percentages are taken as the
pulse width of the PWM signals corresponding to the highest and the
lowest duty cycles that the valves can track. Since the air pumps are
always operating, opening and closing of the valves are the only
factors that affect the airflow into the balloons. In this analysis,
the pressure was expected to remain constant after a peak. However,
unlike shown in Fig. 4, pressure gradually increased as the balloon
was inflated. This discrepancy is caused by the fact that the balloon
is not a perfect, constant radius cylinder. The initial peak in
pressure is observed because the first air that goes into the balloon
has to overcome both the axial stress and the hoop stress of the
rubber. Elongation and corresponding pressure values for a single
balloon under different PWM signals are plotted in Fig. 8. It can be
seen that speed of inflation decreased as lower duty cycles were
employed. The inflation speeds are approximately 3.6, 3.2 and
2.34 cms-1 for 100, 66, 33 % PWM, respectively. It is
also observable that the maximum longitudinal strain decreases with
lower duty cycles. Another observation is that the pressures of 33 and
66 % PWM cycles converge to almost the same value, even though
there is an eight cm difference between the final elongations. This
can be explained with the fact that more on-time of the valves enable
the balloon to keep more air in, hence extending a little bit more.
Elongation (a) and the pressure vs. elongation
(b) of a single balloon inflated with three different duty
cycles of the solenoid valves.
Third, force that a balloon can apply in the axial direction was
measured by an ATI Nano 17 force sensor while the balloon was
constricting in a rigid cylindrical Plexiglas tube of length
1 m. The force sensor was located at the distal end of the
tube. For these experiments, seven new balloons were tested. Each
balloon was inflated while the valve was fully open, and force applied
at the end, when the balloon was fully elongated, was measured for
seven different balloons. The results are presented in Fig. 9. It is
seen that force values increase at a decreasing rate after the
balloons touch the force sensor. After some time, three of the
balloons converged to a constant value of 5 N, two of them
converged to 6.5 N. Assuming full contact with the force sensor,
these force values correspond to a pressure value of 24.8±3.61kPa. It should be noted that this pressure value is
slightly higher than the one in free elongation. It can be deduced
that the pressure builds up as the balloon is constricted in the tube
before either the balloon explodes or comes to equilibrium with
increased pressure where more leakage through the system is
observed. Balloons 1 and 5 exploded, which can be seen as spikes and
vertical drops in the measured forces. The balloons ruptured near the
inlet where they were subjected to high strains.
Forces measured at the distal end of seven balloons
constricted in a one meter long cylindrical tube.
Workspace
The reachable workspace of the robot is almost like an ellipse. The
maximum length the robot can reach is almost 120 cm. This
length is slightly shorter than the maximum length of the balloons
because some of the slack section should be attached to the tip of the
robot. Therefore, this section is never inflated. The minimum radius
of curvature rmin is about 8 cm. However, this
radius heavily depends on the initial curvature of the balloons
utilized. Workspace of the robot is modeled in Fig. 10. An elliptic
shape is obtained because the balloons are not externally constricted
by an obstacle and radial constriction prevents a balloon from
extending sideways just after initial inflation (when rmin
is reached). Side-to-side width of the reachable workspace is about
60 cm.
Reachable workspace, maximum reach and minimum radius of
curvature of the robot. Side-to-side width of the reachable
workspace is about 60 cm.
Navigation experiments
Two sets of navigation experiments have been conducted as follows. In
both of these experiments, the speed of inflation of the balloons was
controlled manually by an operator (the first author) via
potentiometers.
Open field navigation
In this experiment, the robot was navigated in an open environment without
any obstacles. First, the balloons were inflated together to make the robot
go straight. Some rotations due to the structure of the balloons were
encountered, but they were corrected by inflating the balloon on the same
side as the curvature. Then, the robot was navigated to both sides by
inflating a balloon more than the other. Straight-line movement and turning
right are demonstrated in Figs. 11 and 12. Turning to left is almost
identical to what is shown in Fig. 12. All trials were successful in open
field navigation.
Robot elongating by inflating both balloons at the same time.
Numbers are in cm.
Robot turning to the right by inflating one balloon more than
the other. Numbers are in cm.
Maze navigation
In this test, the robot was navigated through a predesigned, maze-like
environment to reach a goal position in the middle of the maze. Maze
walls were cut from 5 mm thick Plexiglas. The robot was placed
in its initial position and guided through the maze using
potentiometers that control the airflow rate into each balloon. The
process of reaching goal position is demonstrated in Fig. 13. In
Fig. 13a and b, the left hand side balloon was inflated more than the
other one so that the robot could rotate rightwards. When the
configuration shown in Fig. 13c was reached, the balloon on the right
was inflated more. However, since it was a tight corner, the balloon
on the left was slightly deflated (Fig. 13d). The same operation was
performed in the configuration shown in Fig. 13e and f as well.
Robot navigating through a maze-like environment.
Discussion
Results of the balloon characterization experiments showed the
capabilities of the actuation system of the continuum robot. The
continuum robot can extend to 1200 mm from its most contracted
form which is 60 mm. This corresponds to an extension of
2000 % which is much higher than the largest strain reported in
the literature (300 %) by Hawkes et al. (2016). The robot is also
is able to achieve its extreme lengths quickly. When the valves are
fully open, the inflation speed is about 3.8 cms-1 and
the deflation speed is around 21 cms-1.
It is necessary to remark that five balloons ruptured during
elongation experiments. Results of these balloons are omitted and
hence not included in the analysis. Since the balloons expand only
from the distal end when pressurized, the greatest amount of reaction
forces arises upon contact of the tip with an obstacle. In transverse
directions, the balloons are highly compliant. Therefore, axial forces
are the only source of effort for the continuum robot. Determining the
force capabilities of the robot with respect to the input pressures is
important, as they may be used to develop a better output force
control method. Thus, the robot can be adapted to different
manipulation tasks. Forces that can be applied by each balloon are
different due to individual structures of the balloons. However,
a value of 4 N can be assumed as a threshold that which a random
balloon may explode if more force is applied. For different materials
and different sized balloons, force-generating capability can be
altered. However, such low values were expected since the balloons,
therefore the robot, have no rigid backbone. This robot can be
suitable for applications where the objective is to reach a goal
position and carry out tasks there with auxiliary devices that would
be attached to the tip.
The navigation tests showed that the robot was successfully controlled
in open field and a maze. When the robot was navigated in open field,
following a perfectly straight line was impossible since the balloons
had an unpredictable slight curvature because of their structure. This
is also related to the manual control of the airflow rates to the
balloons and heavily depends on the skills of the operator. If one or
both of the balloons have a curvature, the deviation from a straight
line is immediately observable. The operator, however, could easily
correct this deviation by changing the inflation speeds of each
balloon. Another problem that was encountered in the navigation tests
that the radius of rotation was different when the robot was rotated
due to the wrinkled structure of the outer sheath. A final remark is
about shortening and re-elongation of the robot. Although elasticity
of the balloons brings the tip of the robot back while the balloons
are deflated, the robot will not be able to return to its initial, the
most compact form without some kind of mechanism to retract the slack
outside of the tip.
The proposed continuum robot serves as a proof-of-concept for a novel
way of pneumatic actuation enabling it to be navigated through
delicate and unstructured environments. Further research may see this
kind of actuation system to be employed in applications such as for
exploratory (Majidi, 2014; Tolley et al., 2014) or medical purposes
(Cianchetti et al., 2014) if higher quality balloon actuators are
used. The proposed design is able to tolerate much higher longitudinal
strains than the examples in the literature (Hawkes et al., 2016), and
is maneuvered with less pressure than the stiffer designs (Sun et al.,
2016). Please note that growth-based soft robots, such as the
very-recent example called vine robots (Hawkes et al., 2017),
can lengthen by thousands of percent from the tip, too. Although the
actuation principles are different, these robots serve to the same
purpose.
The developed robot inherits some of the common disadvantages of
continuum robots such as; modeling difficulties, low force generation
capabilities, controllability issues, the need for bulky external
pressure regulation equipment, and unpredictability and steady-state
positioning errors in control due to their flexible nature (Penning
and Zinn, 2014). Further research on these aspects may help to tackle
mentioned problems and enhance the performance of the proposed
actuation system. Instead of employing off-the-shelf balloons, an
advanced and homogeneous polymer can be utilized to increase
predictability of actuation characteristics. Manufacturing balloon
actuators in an application-specific manner may also allow us to
tailor balloon actuators such that the robot can be optimized for the
application in mind. The shaft design can be improved too, enabling
the balloons to be constricted more tightly to provide better
control. If a more advanced material is used, it can enhance the
controllability and predictability of the robot. Moreover, the
inflation process is not completely reversible. The balloons can be
deflated for some amount. But if it is too much, the slack section
remains behind the tip and it becomes impossible to precisely control
the robot. A mechanism to be located at the tip of the robot may
enable recoiling of the slack of the balloons, thus making the
inflation process completely reversible. Finally, some stiffening
mechanism can be added to the shaft like jamming (Cheng et al., 2012)
to introduce load bearing capability and robot may be made to bare
transversal loads as well as the axial loads.
Conclusions
In this study, we have proposed a novel continuum robot actuated
by two extendable balloons and preliminary characterization experiments were
performed. Motion characteristics of extendable balloons were theoretically
calculated and experimentally verified. The robotic system as a whole was
evaluated in terms of its navigation capabilities in open field and a maze.
The experimental results showed that the performance and capabilities of the
proposed system under different circumstances satisfy our navigation
expectations. Utilizing extendable balloons as pneumatic actuators, enables
the robot to have much more longitudinal strain than the examples found in
the literature. The continuum robot proposed in this study can elongate to
twenty times more in length from its initial controllable position. This
corresponds to a very high extension of 2000 %. Since the backbone of the
robot is guided by obstacles in the workspace, it conforms to the obstacles
and is able to reach a goal position rapidly, especially in substantially
long and narrow environments. Proposed actuation system looks promising and
may be utilized in applications such as medical endoscopy. Further research
is underway to develop a robotic colonoscopy device at our laboratory.
All the data and MATLAB codes can be found in a GitHub
repository. Every result presented in this paper is reproducible. The link is
as follows: https://github.com/eyyarbasi/ContinuumRobot.
The authors declare that they have no conflict of
interest.
Acknowledgements
This work was supported by the Scientific and Technological Research Council
of Turkey (TUBITAK, # 115E717).
Edited by: Chin-Hsing Kuo
Reviewed by: Yigit Menguc and one anonymous referee
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