IEEE Robotics & Automation Magazine - March 2022 - 73

Dexterous Instruments Comparison
(Surgical Task B.3)
80
90
Performance
In these trials, participants had to perform the more complex
task of avoiding obstacles during pick-and-place tasks while
using mechanisms that are closer to surgical reality, such as
foot clutches to control tool movements. The participants
adapted differently to the primary control with a broad performance
range both in terms of the execution time and the
number of collisions with the virtual anatomic structures, as
presented in Figures 11 and 12 and Tables 1 and 2. For each
user, we identified which of the four different shaft/grasper
combinations achieved his/her best performance both in
terms of the time needed to complete the task and the number
of collisions with the virtual anatomical structures. Comparing
the performance of a single user using four different
tools, a lower number of collisions was achieved when using
the elbowed tool. This was the case for five out of 10 lay users
using the E 3 F, and for six out of 10 using the E DV. Some of
them achieved the same score with multiple tools while only
three of them achieved their best score using the W DV tool,
and none of them did so using the W 3 F device. From these
results, it appears that the E 3 F helped to avoid anatomical
obstacles when compared to the use of a less dexterous tool
by the same participant. The kinematic control of the two
graspers was also compared, but there was no significant difference
in using different graspers. Dexterity of the shaft
affected performance more than end-effector dexterity (DV
or 3 F). From the UEF it emerged that increased complexity
of the tool shaft was often an obstacle to intuitive control,
leading to increased control effort for half of the participants.
The simpler tool was preferred by six out of 10 users, but for
40% of participants, the E felt more natural because it was
similar to the human arm and consequently more intuitive.
However, after a short learning period, it became apparent
that most of the users could adapt quickly to the E shaft. Furthermore,
the best performance (nine out of 10 users) was
achieved in the second attempt when using either the W or E
shaft, in any order of the task performance. The surgeons
performed similarly to the lay participants, having experienced
the same adaptation to the more dexterous patient side
manipulators,
different from the one they currently use on
the Da Vinci robot.
Questionnaires
The SUS resulted in a median score of 63.75 and 57.5 for lay
participants and surgeons, respectively (Figure 13). The
results confirmed that the system was not immediately easy
to use and required a short training time. These results differ
from the first two trials and the simple pick-and-place
scenario. The NASA-TLX questionnaire produced median
scores of 46.33 for the E 3 F, 62.83 for the E DV, 62 for the W
3 F, and 59.83 for the W DV. For surgeons, the median score
was of 62 for the E 3 F, 63 for the E DV, 32.3 for the W 3 F,
and 56.67 for the W DV (Figure 14). The Wilcoxon test
70
60
50
40
30
20
10
NASA-TLX
Figure 10. The NASA-TLX scores for surgical task B.2.
Wrist
Elbow
Time to Complete the Task
350
300
250
200
150
100
50
E_3F E_DV W_3F W_DV
Tested Tools
Figure 11. The task completion times for the four shaft/endeffector
combinations in surgical task B.3.
Collisions With Obstacles
200
150
100
50
E_3F E_DV W_3F W_DV
Tested Tools
Figure 12. The number of shaft collisions with the virtual objects
for the four shaft/end-effector combinations in surgical task B.3.
MARCH 2022 * IEEE ROBOTICS & AUTOMATION MAGAZINE *
73
Collisions
Time (s)
Score
IEEE Robotics & Automation Magazine - March 2022

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