IEEE Robotics & Automation Magazine - March 2021 - 97

Comparison Between the Soft Robot
soft swab bent horizontally to the sampling point on the
and Medical Doctor
other side of the throat (7 s) and scraped for the second
Figure 7(a) displays the medical doctor scraping the palacollection (8 s).
toglossal arch part rapidly downward. The corresponding 3) After the collection procedures, the soft swab was unpresapplied force along the x, y, and z axes during that process
surized (10 s) and left the mouth (11 s).
is represented in Figure 7(b)-(d). The force along the During the process displayed in Figure 8, the volunteer found
three directions in each case shows a trend of increasing no discomfort and pharyngeal reflex.
to a peak value and then returning to the relaxed state. We
We further recorded 15 human subjects' feelings with
collected N = 25 sets of scrape force measurements gener- both the medical rigid throat swab and our soft robotic swab.
ated by the medical doctor during the sampling process, One subject preferred the medical rigid throat swab, five subthe average force of which was 0.31 ± 0.26 N (mean ± jects preferred the soft robotic swab, and nine subjects
standard deviation).
thought the two swabs brought similar feelings. More than
Next, we compared the soft robotic swab's sampling 90% of the tested subjects said that the soft robotic swab
motion at the same palatoglossal arch part. As Figure 7(e) would not reduce comfort compared with the cotton swab.
expresses, there are two processes during the sampling
motion of the robotic swab. First, the collecting segment Discussion and Conclusions
was inflated with 80 kPa at 1.1 s, forcing the tip to glide In this article, we proposed a soft robotic throat swab system
downward with a peak force value at 2.8 s [Figure 7(f)-(h)]. for sputa collection in the detection of viruses. The soft swab
After releasing the collecting segment, the bending actuator consists of a tapered origami collecting segment and a tapered
was inflated with 100 kPa to achieve a similar downward bending actuator. We used a combination of numerical analslope motion to the medical doctor. The force reached yses and experiments to investigate the parametric design of
another peak value at 4.9 s. The force values of the soft the soft swab. We found that the optimized tapered Yoshimura
robotic swab (0.41 ± 0.05 N) were slightly larger than those origami collecting segment yielded appropriate elongation
of the medical doctor (0.31 ± 0.26 N). Three repeated trials and twisting motions, which allows for effective throat
were conducted. See the third section
of the supplementary video for more
details of the comparison.
0 kPa
70 kPa
100 kPa
Compared with the sampling
S, Mises (Mpa)
motion of the medical worker, our
(Avg: 75%)
+1.242e-01
results demonstrate that the motion
and applied force of our soft robotic
swab are very similar to the doctor's
motion, which suggests that our soft
robotic swab can accomplish professional medical sample collection.
With permission of research ethics
+0.000e+00
oversight from Beihang University
(a)
(BM20200179), we conducted the
entire sampling process of the soft
robotic throat swab system on a human
Inflate Bending Actuator
volunteer (Figure 8 and the fourth secInflate
tion of the supplementary video). The
Collecting Segment
Inflate
2
process was divided into three steps:
Collecting Segment
1) The soft swab was moved in front of
1
the patient with the tip facing the
3
mouth (0-3 s). Guided by the feedback of the video camera, the nonpressurized soft swab entered the
Scraping
Scraping
throat via the motion of the robotic
arm (4 s).
2) After arriving at the throat's sampling
(b)
location, the collecting segment was
inflated to scrape the throat for the Figure 6. The interaction between the soft robotic swab and throat. (a) The numerical
first collection (5 s). After completing results illustrating that the tip of the robotic swab slips down along the throat surface
with the collecting segment elongation. (b) The FITR images highlighting the scraping
the collection on one side, the collect- area range of the soft robotic swab (see the second section of supplementary video).
ing segment was released. Then, the Scale bar = 5 mm. Avg: average; S, Mises: von Mises stress.
MARCH 2021

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IEEE Robotics & Automation Magazine - March 2021

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