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IV. USER EVALUATION
The goal was to explore if there is a difference in the UX
between a robot with remote-HRI (robot A) and a technical
revised version of this robot with physical-HRI (robot B).
Both robots offered two control modes: remote control via
touch-panel and direct-manual control via physical guidance.
The touch-panel for remote control featured a graphical user
interface consists of buttons to steer the robot and to save the
taught movement trajectories. The physical-HRI mode
enabled the operators to control the robotic arm directly,
manually and without an additional intermediate layer. Robot
A was optimized for remote control, whereas the
improvement of robot B consisted of an extended physical
HRI. Five participant were recruited to participate in the two
studies. This small participant number can be sufficient to
identify the most severe usability problems and was already
discussed by [9].
The current study was conducted one year after the
previous one. Within this time, robot A was upgraded to robot
B, so robot B could only be examined after robot A. However,
both studies had the same structure: (1) Introduction of the
robot: Each participant was introduced to the robot and its
control mechanisms. The participants were assigned the task
to parameterize the process points in a predefined robot
program. That means they had to bring the robot’s tool to a
precise position above the screw and that they had to adopt
the position parameters to a program in the UR-teach pendant
(for robot A) or to the XROB-user interface. Fig. 1 shows the
screw positions as process points. For process quality
precision of the parameterization is crucial. As Fig. 5 points
out especially lateral or orientation deviances are critical for
process effectivity while vertical positioning could be
effectively observed visually during teach in process.
Fig. 5 - screwing process - error sources & real view
In order to relief stress and increase compliance, the
participants were assured that the focus of investigation was
only the robot’s performance and there were no negative
implications for them. (2) Conducting the user study: Each
participant was audio- and videotaped with two cameras in
order to generate a holistic perspective. This included a head
mounted camera (first-person view - Fig. 6) and a hand
camera (context oriented view). (3) Post-study
questionnaires, including NASATLX, SUS, and self-
developed items. The aim of the analysis was to compare the
temporal demand, and the UX (including usability and performance expectancy) of the first and second version of
the robot prototype. The findings are used for a the third (and
last last) technical revision (design of the user interfaces of
robot C, D and E) before the robot is deployed in the normal
factory environment. The analysis of the video data
(comments, reactions and feedbacks) consisted of (1) a rough
clustering of all relevant issues, (2) a detailed description of
their key features, and (3) overlapping topics were merged to
categories or differentiated from each other.
Fig. 6 – Head Mounted Device for gaze tracking - gaze tracking results
V. RESULTS
A total of five male assembly workers were recruited to
participate in both studies (a representative sample for the
factory with which we collaborated). The sample might be
rather small but even for companies with several 1000+
employees it was difficult to find workers who work at a
special part of the assembly line, predictively for the whole
project duration (2 years+) who fulfill requirements (left- /
right-handedness, age, robot training,…). Each participant
was interviewed for 30 minutes and filled in demographic
questionnaires afterwards. The mean age of the study
participants was 45.4 (SD=5.7) and they had no prior
experience with robotic systems. Four out of five participants
had experience with computers and automated systems
previous to the studies.
The teaching using robot A yielded requirements regarding
robot hand guidance. Gear friction yields stacking and
imprecise movement. Locking of certain degrees of freedom
(e.g. rotation or translation,…) is asked for by the users as
well as semiautomatic tool alignment and expected to
improve both programming time and process quality.
A state of the art force torque sensor was integrated (in
robot B) as well as buttons to call perpendicular realignment
or locking of rotational or translational degrees of freedom.
That should make the robots more effective. Additionally a
RGB-D sensor as well as a 2D sensor for position deviation
correction were added (see Fig. 7). Robot B was evaluated
with exactly the same assignment of parameterization of the
process points. The teaching duration using remote (robot A)
and physical (robot B) control mode was extracted from the
video recordings. Table I shows a decrease in average
duration by 23.11%, and a strong shift from software- to
47
Proceedings of the OAGM&ARW Joint Workshop
Vision, Automation and Robotics
- Titel
- Proceedings of the OAGM&ARW Joint Workshop
- Untertitel
- Vision, Automation and Robotics
- Autoren
- Peter M. Roth
- Markus Vincze
- Wilfried Kubinger
- Andreas Müller
- Bernhard Blaschitz
- Svorad Stolc
- Verlag
- Verlag der Technischen Universität Graz
- Ort
- Wien
- Datum
- 2017
- Sprache
- englisch
- Lizenz
- CC BY 4.0
- ISBN
- 978-3-85125-524-9
- Abmessungen
- 21.0 x 29.7 cm
- Seiten
- 188
- Schlagwörter
- Tagungsband
- Kategorien
- International
- Tagungsbände