Proceedings 2003 IEEE International Symposium on
Computational Intelligence in Robotics and Automation
July 16-20, 2003, Kobe, Japan

Designing a Robot as Communication Media–The Eﬀect of Head and Body Movement on Co-Present’s Impression–
Hideaki Kuzuoka∗
Inst. of Eng. Mechanics and Systems
University of Tsukuba
krystal.esys.tsukuba.ac.jp/~kuzuoka/

Jun’ichi Kosaka
Inst. of Eng. Mechanics and Systems
University of Tsukuba
krystal.esys.tsukuba.ac.jp/~kosaka/

Shin’ya Oyama
Keihanna Human Info-Communication Research Center
Communications Research Lab.
www2.crl.go.jp/jt/a131/Keiichi Yamazaki
Dept. of Fine ArtsSaitama University
www.kyy.saitama-u.ac.jp/2002e/Frame_c_04.html

Haruo NomaMedia Information Science Lab.
ATR
www.atr.co.jp

Akiko Yamazaki
Dept. of System Information
Future University Hakodate
www.fun.ac.jp/en/faculty/index.html

Abstract

GestureLaser
Laser spot actuator

We have been developing robots as communication media. This paper focuses on the latest development
named GestureMan 2. We used ATLAS which wasdeveloped at ATR to control the robot in proportion
to a remote person’s walking and head movement. Our
experiment with the system showed that co-present persons got better impression on the robot when it was controlled with a conventional joystick. From this result,
we noticed that for this kind of robot to have an aﬃnity
to people, not only its ﬁgure but also its motion should
be properly designed.

1

camera unit
tiltingmechanism
verticalpole

Introduction

When a video mediated communication system is used,participants occasionally ”encounter diﬃculties in making sense of each other’s conduct even when undertaking seemingly simple actions such as pointing to objects
within a particular environment ([1], p.121)”
Our idea to challenge this problem is to use a robot
as communication media. For example, in order to assist remote pointing, we have developed a remote control laser pointer named the GestureLaser[4]. Then wemounted it on a mobile robot named the GestureMan[2]. However, the system could not perform pointing aswell as people do in co-existing situation. One of themain reasons for this problem is lack of resources thatclearly shows a remote person’s (a person who remotelycontrols the robot) orientation and frame of reference.
In order to alleviate this problem, we developed a newrobot that has clearer resources to indicate orientations.
Then, we have conducted an experiment to control therobot in proportion to a remote person’s motion.

∗Acknowledgement: The research was supported by Telecommunications Advancement Organization of Japan, Japan Society
for the Promotion of Science, Oki Electric Industry Co. Ltd.,and Venture Business Laboratory (VBL) of Ministry of Education, Culture, Sports Science and Technology. We also thank theCommunications Research Laboratory for assisting part of thecomputer network between University of Tsukuba and ATR.

0-7803-7866-0/03/$17.00 ©2003 IEEE

PC and wirelesstransmission unitsrobot base

Figure 1: GestureMan
In this paper, based on the experiment, we will discuss how the head and body movement of a robot aﬀect
a co-present’s (a person who co-exists with the robot)
impressions on the robot. Also we will try to elicit somedesign implications for a robot as communication media.
In the next section we start from describing our previous robot named GetureMan. Then, after introducing
a newly designed robot: GestureMan 2, we describe ourexperiment to control the robot in proportion to a remote person’s body motion. Finally, we will discuss theresults of the experiment.

2

GestureMan

GestureMan (ﬁg. 1) consists of a robot that can movearound a remote domain. It has three cameras and alaser pointer on its top. In a remote domain, a remoteperson sits in front of a three screen system. (ﬁg. 2). A50

three-camera unit

Figure 2: Three screen system
remote person moves the robot by a joystick. The laser
pointer is controlled by a mouse and pressing the mousebutton makes the laser dot brighter. This is a way of
distinguishing movement of the laser dot from pointing
with it. Participants speak to each other via wirelessheadsets and microphones.
Through the experiment we could recognize someproblems of GestureMan [1]. In this paper, we focus
on the following problems:• A red dot of the laser pointer appears apart fromthe robot and there is not enough resource to determine where the remote participant is looking at.
Therefore, sometimes it is hard to ﬁnd the red dot
in the environment.
• Since the laser spot is kept turned on, it lies on thesurface of an object. Thus a local participant occasionally misunderstands that the remote participant is keep discussing on that particular object.
These problems occur because, as it can be imaginedfrom ﬁgure 1, GestureMan has a little clue to tell where aremote participant is orienting to. Then it was suggested
that the following considerations might be relevant to
the design and development of an improved system:• Provide participants with the ability to determine
the location, orientation and frame of reference ofothers;• Provide resources through which participants candiscriminate the action of others which involve
shifts in orientation and reference to the space
and a range of objects, artifacts and features.

GestureLaser

Figure 3: GestureMan 2to. Pan and tilt motion of the head are enabled by two
motors at the neck. In this way, the robot can show both
body orientation and head orientation independently. Inorder to clearly express body orientation shoulder-likeshapes are attached to the body.

3.2

GestureLaser

GestureLaser is a remote control laser pointer that wasdeveloped by the authors [4] and it is attached to therobot’s body. A remote participant controls the laser
spot by a mouse. The laser beam is emitted only whena left mouse button is pressed. Otherwise the laser isturned oﬀ completely.

3.3

Control the Robot by Human Motion
Tracking

For the robot head of the Gestureman 2 to be an eﬀective resource for communication, it should be controlled
to accommodate a remote person’s intention to look at
objects in an environment. We used a joystick to control a head of previous GestureMan. Although a joystick
worked quite well, it is clear that a robot head does not
move as frequently as people do. Therefore, we decided
to control the robot by tracking motion of a remote person.

In the next section, we’ll introduce our new systemthat aims to alleviate these problems.

3

GestureMan 2

We designed a new robot that has more resources toshow a remote person’s orientations than the GestureMan. We named he new robot GestureMan 2 (Fig. 3).

3.1

Head and Body Design

Three-camera unit is mounted at the head of the robot.
Each lens has 60 degrees of horizontal ﬁeld of view thus
a remote participant can get 180 degrees of horizontal
ﬁeld of view in total.
Three-camera unit is covered with a white helmet sothat it looks like a head. Also two ears and a visor are
attached to a helmet. In this way the head gives local
participants a clue where the middle camera is orienting

Figure 4: ATLASFor this purpose, we used a locomotion interface
named ATLAS developed by ATR [3]. It is a treadmill-51

like locomotion interface. A user can get the sensationof walking on ﬂat ground or on a slope. We mount a
CCD camera with an infrared light ﬁlter and an infrared
lamp in front of the treadmill. The relative positions of
the small IR reﬂection markers attached to each ankle of a user are measured by a video-tracking system(OKK QuickMug) and determines the speed of the beltof the treadmill. When a user steps sideways, the wholesystem turns to compensate for the user’s walking direction. Using the ATLAS, we can control the robot’sforward, backward, and turning motion in response to aremote person’s walking action. Forward motion speed
is determined in proportion to a remote person’s walking
speed.
We also use a head mounted display (HMD) witha magnetic position sensor. A magnetic sensor enables
to control the robot’s head in proportion to a remoteperson’s head motion. An HMD shows an image captured by a three-camera unit. However, we used only themiddle camera among three cameras because the HMD
is only capable of showing one video signal at the sametime.
The GestureLaser is controlled by a small handheld
track ball unit. We did not control the laser in proportion to a remote person’s arm motion because a remoteperson do not have to keep his/her hand up when he/shewants to keep pointing at a certain object.
For voice communication, a remote person wears aheadset. A co-present wears a wireless microphone totransmit his/her voice to a remote person. A remoteperson’s voice can be heard from a speaker imbedded in
the robot’s head.

4Remote Guide Experiment

We have conducted a preliminary experiment to examine the eﬀect of using ATLAS as an user interface for aremote person.

4.1

Experiment Design

The GestureMan 2 resided in a room at the Universityof Tsukuba and the ATLAS was installed at ATR. Twosites were about 400km apart and the Japan Gigabit
Network (JGN) was used to transmit audio/video signaland robot control commands.
At the university, six posters that explains diﬀerent research topics were posted in the room. These research topics were categorized into two research areas,
i.e. virtual reality and tele-conferencing and each area
consisted of three posters. A remote person at ATR
controlled the robot and guided a co-present (subject) toposters to explain about research topics. When each session started, a co-present chose one course which seemed
to be more interesting for him/her.
We compared two control modes; joystick mode andATLAS mode (Fig. 5). Only the middle camera of therobot was used for both modes. 10 university students
served as co-present for each mode. On the other hand,
only one researcher of ATR served as the remote person.
As a reference, we did the same poster session under
the face-to-face setting. The same researcher of ATR
actually came to the university and guided 10 subjects.
For later analysis, all the sessions were video tapedand questionnaires were given to all subjects.

magnetic sensor

ATR

University of Tsukuba

audio/videoaudio/video

JGN

audio

LAN

monitorjoystick

GestureMan 2Figure 5: Overview of the experiment

4.2

Result

Before the experiment, our hypotheses to this experiment were as follows:• ATLAS mode was superior for a co-present in recognizing where a remote person was looking at.
• A co-present had better impression on the robot
when it was controlled in ATLAS mode because
its head and body motion were natural.
In this section we will discuss the result of the experiment based on the video analysis and questionnaires.

Behavior analysis
During the experiment, a remote user moved the robot
from one poster to another. Posters were intentionallyplaced so that the robot should move from one side to
the other side of the room. A remote person turned
the GestureMan’s head to look back and forth between
posters and a co-present just like people commonly dowhen they are co-existing (Fig. 6).
These kinds of attitudes of the robot were observedin both control modes. We counted the number of thiskind of head turns and it turned out that the head wasturned less often during the joystick mode (Fig. 7).

Figure 6: An example that robot turned its head.
When the robot roved, however, it moved faster during joystick mode compare to ATLAS mode. Figure
8 shows the average time that the the remote person
waited for a subject. Negative numbers indicate that a52

number of looking around / minn

Table 1: Extracts from questionnaire 1 (overall impressions).

5

3.83
4

3.19

1.
2.

3
2

3.
4.
5.
12.
15.
16.

1
0ATLAS

Joystick17.

Figure 7: Number of head turns per minute.

24.

Average waiting time (sec)subject waited for the remote person. Steel-Dwass test
showed that there was statistically signiﬁcant diﬀerence(p < .05) between each mode.
This result was mainly due to the diﬀerence of parameter setting between ATLAS mode and joystick
mode. For instance, the maximum speed of the robot
was diminished due to the software limitation. Although
this result was quite opposite from our expectation, we
are now interested in how this diﬀerence of motion affected subjects’ impressions on the robot.

Did you feel aﬃnity to the guide?
Did you think the guide was dependable?
Did you feel the guide was lovable?
Was the robot’s roving clumsy?
Was it easy to follow the guide?
Were you irritated by the red dot?
Were you aware of the guides gaze?
Was it easy to recognize where the guide waslooking at?
Was it easy to project where the guide wasaiming at?
Were you tired?

Table 2:Extracts from questionnaire 2 and 3(head/body impressions)
1.
3.
8.
11.
13.
15.

sensitive ⇔ dull
quick ⇔ slow
safe ⇔ dangerous
lovable ⇔ hatefulgood ⇔ badnatural ⇔ artiﬁcial

2
10able and natural compare to ATLAS mode. There wereno signiﬁcant diﬀerence in any items in questionnaire 3.

-1-2-3

5-4-5
ATLAS

Joystickface-to-faceFigure 8: Average time to wait for the robot.

Questionnaire
After the session, we asked each subject to answer threekinds of questionnaires. First one (table 1) asked theoverall impressions on the robot. Second and third one(table 2) asked the impressions on the robot’s head andbody motion respectively. Please notice that we calledthe robot as ”guide” in this questionnaire.
Firstly after the session, subjects answered 27 items
in questionnaire 1 using a 5-point scale ranging from 1(not at all) to 5 (very much). Then, subjects answeredquestionnaire 2 and 3. There were 16 adjective pairs(opposite in meaning) in each questionnaire and subjects
chose responses from 5 point scale.
In case of the questionnaire 1, Wilcoxon rank sum
test showed that there were signiﬁcant diﬀerences (p <.05) in item 1, 2, and 24 (printed in bold face in table1). For instance, joystick mode was preferable in terms
of aﬃnity, dependability, and fatigue.
In case of questionnaire 2, Wilcoxon rank sum test
showed that there were signiﬁcant diﬀerences (p < .05)
in item 11 and 15 (printed in bold face in table 2). For
instance, head movement in joystick mode was more lov-Discussions

First of all, we could not prove our hypothesis that theATLAS mode is superior for a co-present in recognizing
where a remote person is looking at. In this paper, however, we focus on the eﬀect of a robot’s head and body
movement on co-present’s impressions on the robot. Especially we are interested in clarifying why joystick mode
was superior in terms of impressions.
Co-presents thought the robot was more dependable
during joystick mode. As shown in ﬁgure 8, duringface-to-face mode, the guide (”remote person” in othermodes) arrived at the next poster to be explained before co-presents. Thus we could assume that subjects
felt the guide was dependable when he always led subjects. Therefore, we think that subjects felt the robot
was less dependable during the ATLAS mode because
they had to wait for the robot longer compare to thejoystick mode.
In terms of the robot’s head, subjects thought thatits movement was more lovable and natural during thejoystick mode. We are going to discuss some reasons forthis from the aspects of the frequency of head rotation,
head rotation angle, and head rotation speed.
At ﬁrst, as shown in ﬁgure 7 the head moved more
frequently during the ATLAS mode. However, this ﬁgure shows only major movement of the head. Actually,during the ATLAS mode, there were much more small
and frequent movement in response to the remote person’s actual head movement. Of course this kind of motion was not seen during joystick mode.
For this experiment, only the center camera of thethree-camera unit was used. Its ﬁeld of view is 60 de-53

grees horizontally and 45 degrees vertically and it is ofcourse much narrower than human eyes. Therefore, inorder to look at a certain object via the robot, a remoteperson had to turn the robot’s head more than a people
normally does. Especially when the remote person wore
HMD, he tended to look at an object at the middle ofhis ﬁeld of view and this made the motion of the robot’s
head unnaturally large. On the other hand, when theremote person was using the joystick, he tended to stopturning the robot’s head soon after the object appears
at the edge of the monitor. Thus, during the ATLAS
mode, the robot’s head tended to turn much larger than
the joystick mode.
In case of the ATLAS mode, the maximum rotation
speed of the robot’s head was faster than the joystickmode in order to catch up with the motion of the remoteperson’s actual head motion. On the other hand, in caseof the joystick mode, the maximum speed was reduced
due to the controllability. As the robot’s head turned
faster, it made larger noise from gears. Thus, during theATLAS mode, the robot’s head turned faster with morenoise compare to the joystick mode.
In summary, the robot’s head turned more gently
during the joystick mode compare to the ATLAS mode.
We are assuming that these were the main reasons why
subjects got better impressions on the joystick mode. Itis quite interesting that simpler head motion during thejoystick mode made subject feel that it is more natural.
We can assume that such motion seemed to be ”natural”
for that kind of robot design. We can also assume thatthe diﬀerence of the head motion led to the diﬀerence ofaﬃnity and tiredness.
Another interesting result about the head movement
is that although the robot’s head during ATLAS modetended to direct more precisely toward objects, it did
not make any diﬀerence to items from 15 to 17 of thequestionnaire 1.
This is still a preliminary experiment and we cannot
clearly conclude that which factors are dominant for theresults of subjects impressions. However, our previous
study and results in this paper gives us following design
implications;[2] Hideaki Kuzuoka, Shinya Oyama, Keiichi Yamazaki,Akiko Yamazaki, Mamoru Mitsuishi, and KenjiSuzuki. Gestureman: A mobile robot that embodies a remote instructor’s actions. In Proc. ofCSCW2000, pages 155–162, 2000.
[3] Haruo Noma and Tsutomu Miyasato. A new approach for canceling turning motion in the locomotion interface, atlas. In Proc. of ASME-DSC-Vol.67,
pages 405–406, 1999.
[4] Keiichi Yamazaki, Akiko Yamazaki, Hideaki
Kuzuoka, Shinya Oyama, Hiroshi Kato, Hideyuki
Suzuki, and Hiroyuki Miki. Gesturelaser and gesturelaser car: Development of an embodied space tosupport remote instruction. In Proc. of ECSCW’99,
pages 239–258, 1999.

• The robot should provide resources for a co-present
to determine a remote user’s orientation.
• However, it may not be necessary for such resources to precisely direct to a certain object.
• It is important to design how fast, how much, andhow often such resources to be moved.

6Conclusions

We have developed robots as communication media
named GestureMan 2. We controlled the robot in proportion to a remote person’s walking and head motion.
Our experiment with the system indicated that for thiskind of robot to have an aﬃnity to people, not only its
ﬁgure but also its motion should be designed properly.

References[1] Christian Heath, Paul Luﬀ, Hideaki Kuzuoka, Keiichi Yamazaki, and Shinya Oyama. Creating coherent environments for collaboration. In Proc. of ECSCW2001, pages 119–138, 2001.

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