IEEE Robotics & Automation Magazine - March 2022 - 71

dexterity of the two end effectors (DV and 3 F grasper) shown
in Figure 2 while keeping the shaft of the instrument rigid.
Articulated Shaft Comparison (Surgical Task B.2)
The aim of this experiment was to compare the performance
of instruments with rigid and articulated shafts while having
the same type of the grasper (DV EndoWrist). The participants
used a standard DV tool enhanced with a W with 3 rotational
DoF, as in the DV EndoWrist. The instrument's shaft
with an additional E placed at 3.75 cm from the tooltip along
the shaft added an additional DoF to the shaft. The tasks in
this study are the same as in the user study. Ten participants
took part in this study, including one surgeon experienced in
robotic surgery.
Dexterous Instruments Comparison
(Surgical Task B.3)
We further investigated different combinations of shafts and
graspers to carry out a more complex surgical task. Four different
combinations of shafts and two grasper types (used in the
first two studies) were compared: 1) a tool shaft with a W and
DV grasper, 2) a tool shaft with a W and 3F grasper, 3) a tool
shaft with an E and DV grasper, and 4) a tool shaft with E and
3F grasper. The task was to pick up colored objects and place
them in the corresponding color boxes, with the right or the left
hand, one at a time (Figure 4). The colored boxes were placed
inside the cavities and behind tubular obstacles, which posed
additional difficulty for moving and maneuvering the virtual
surgical tools. The users were asked to complete the task four
times, with each shaft/end-effector combination. In this trial,
motion of the shafts was partially constrained, emulating trocar
points inside the patient. Additionally, as in the real surgical
system (DV robot, Intuitive Surgical, Inc.), we used a clutch to
lock/unlock the tool motion to avoid uncomfortable upperbody
and arm poses of participants. The clutch was controlled
by a pedal. The study was performed 10 ten lay users with no
previous experience in teleoperation and three surgeons experienced
in using the DV surgical robot. For each trial, the time
needed to complete the task and the number of collisions registered
between the tools and the obstacles were recorded.
Results
Articulated Tooltip 1 Comparison
Performance
The time and velocity of each transfer were recorded, and the
mean and standard deviation were computed for each subject.
The mean time and velocity among participants were compared
using the two tools. The results show a noticeable difference
between the two-fingered DV grasper tool and the 3 F
anthropomorphic grasper, both in terms of duration and speed
of performing the task. For lay users, the mean transfer time
was 2.6 ± 1.3 s and 3.4 ± 1.5 s when using the DV and 3 F
graspers, respectively. For surgeons, the mean transfer time
was 2.7 ± 1.6 s and 3.5 ± 1 s for the DV and 3 F graspers,
8
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4
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2
1
Duration (s)
(a)
daVinci 3 F
Figure 5. (a) The mean transfer duration and (b) velocity for
surgical task B.1.
MARCH 2022 * IEEE ROBOTICS & AUTOMATION MAGAZINE *
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2
Velocity (cm/s)
(b)
respectively. The mean velocity for lay users was 8.7 ± 3.1 cm/s
and 7.1 ± 2.6 cm/s for the DV and 3 F graspers, respectively. For
surgeons, the mean speed was 9.1 ± 4.1 cm/s and 7 ± 2.5 cm/s
for the DV and 3 F graspers, respectively (Figure 5). All the
Figure 3. The virtual setup has six colored squares and nine colored
pegs. The task is to move the squares to the same-color pegs.
Figure 4. In the designed training, task users have to move colored
boxes to the target platform behind the tubes using the correct
instrument (in this case, left).
IEEE Robotics & Automation Magazine - March 2022

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