ChiCaRo: Tele-presence Robot for Interacting with Babies andToddlers
Kasumi Abea, b, c, Masahiro Shiomia, Yachao Peib, Tingyi Zhangb,
Narumitsu Ikedad and Takayuki Nagai bac

ATR-IRC, Kyoto, Japan; bThe University of Electro-Communications, Tokyo, Japan;

JSPS Research Fellow, Tokyo, Japan; dThe University of Tokyo, Tokyo, Japan*corresponding author: Masahiro Shiomi, m-shiomi@atr.jp
Kasumi Abe received her B. Eng, M. Eng and Ph.D. degrees from the University of ElectroCommunications, in 2009, 2011 and 2015. She is currently a Research Fellow of the Japan
Society for the Promotion of Science. Her research interests include human-robot interaction
and robotics for childcare. She is a Member of the RSJ and JSAI.
Masahiro Shiomi received M. Eng. and Ph.D. degrees in engineering from Osaka University in2004 and 2007. From 2004 to 2007, he was an intern researcher at the Intelligent Robotics andCommunication Laboratories (IRC). He is currently a group leader in the Agent Interaction
Design department at IRC, Advanced Telecommunications Research Institute International(ATR). His research interests include human-robot interaction, robotics for childcare, networked
robots, and field trials.
Yachao Pei received M.Eng degree in engineering from The University of ElectroCommunications in 2015. He is currently working toward the Ph.D degree in electricalengineering in the Department of Mechanical Engineering and Intelligent Systems, theUniversity of Electro-Communications. His research interests robot mechanical engineering andhuman-robot interaction.
Tingyi Zhang received her B. Eng and M. Eng degrees from the University of ElectroCommunications, in 2015 and 2017. She is currently working on the Mitsubishi UFJ
Information Technology, Ltd.
Narumitsu Ikeda received B.Eng. from The University of Electro-Communications, Tokyo,
Japan, in 2017. He is currently a graduate student at The University of Tokyo. His researchinterests include computational neuroscience, neuromorphic computing, emergence,
neurorobotics.

Takayuki Nagai received his BE, ME and DE degrees from the Department of ElectricalEngineering, Keio University, in 1993, 1995 and 1997, respectively. Since 1998, he has beenwith the University of Electro-Communications where he was an Associate Professor of the
Graduate School of Informatics and Engineering, and is currently a Professor since. From 2002
to 2003, he was a visiting scholar at the Department of Electrical Computer Engineering,
University of California, San Diego. Since 2011, he has also been a Visiting Researcher at
Tamagawa University Brain Science Institute. He is a Member of the IEEE, RSJ, JSAI, IEICE
and IPSJ.

ChiCaRo: Tele-presence Robot for Interacting with Babies andToddlers
The progress of super-aging societies is decreasing opportunities for interaction
between grandparents and grandchildren due to increased nuclear families. This
paper reports a tele-presence robot named ChiCaRo, which is designed topromote interaction with babies/toddlers and encourage remote communication
between grandparents and grandchildren. We experimentally investigated
ChiCaRo’s social acceptance with 17 adults and 19 children in a play room
environment. The adult participants evaluated ChiCaRo highly in the context ofremote interaction with their children. Next we conducted field trials in real homeenvironments with three nuclear families and their grandparents who operated
ChiCaRo to investigate its effectiveness. After one-week field trials, thegrandparents reported that ChiCaRo encouraged both interaction with their
grandchildren and supplemented childcare, e.g., watching babies/toddlers insteadof their parents.
Keywords: child-robot interaction; tele-presence; childcare

1. Introduction
For such developed countries as Japan and Germany, falling birth rates andaging populations are huge problems. To tackle them, robotics researchers continue tofocus on the physical and mental support of elderly people through interaction withrobots: socially assistive pet robots for mental support [1], autonomous wheelchairrobots for locomotion support [2], shopping support robots for daily activity support [3],information-providing robots for elderly people in care home environments [4], andtele-operation robots as conversation partners [5].
However, to tackle problems in super-aging societies, both supporting elderly
people and increasing birth rates are important issues. Past research reported that
supporting childcare is essential to raise birth rates, and the role of such support is often
assumed by grandparents [6]. Aging populations increase the number of nuclear

families [7], and living apart obviously increases geographic distance, which is a strong
factor that reduces the frequency of contact between grandparents and their
grandchildren [8] by decreasing the interaction opportunities. In fact, the average periodof contact between grandparents and grandchildren is roughly one month or less [9].
Another work reported that the decline in the frequency of contact is acceleratingcompared to about 40 years past [10]. These factors must be tackled if opportunities forinteraction between grandparents and grandchildren are to be increased in the context ofchildcare support.
Unlike various works that support seniors through robots, relatively scantattention has focused on supporting childcare. A few research works have proposed
supporting childcare using robots, e.g., sensor networks and/or wearable sensors torecognize the behaviors of young children (mainly four to six years olds) inkindergarten environments and easing the paperwork burden of childcare workers [11][12], a robotic toy box that motivates young children to pick up their toys [13], andinvestigating the social acceptance of robot childcare support systems [3]. Several telepresence robots are used in preschools and kindergartens [14-19]. These research works
developed robots systems and investigated their effectiveness in particular tasks or
education support contexts for young children; however, they less focused on increased
opportunities for interaction with in home environments. The social acceptance andeffectiveness of such tele-presence robots from the viewpoints of parents andgrandparents also remain inadequately investigated.
In this research work, we developed a tele-presence robot named ChiCaRo(Child-Care Robot) that can interact with babies and toddlers and conducted web-based
surveys and gathered more than 200 opinions about its appearances and functions. We
conducted an experiment with ChiCaRo in a playroom environment to investigate social

acceptance toward it from parents/grandparents in the context of remote interaction withbabies and toddlers (Fig. 1). Next, we conducted a field trial in real home environments
to investigate its effectiveness, i.e., whether it encourages interaction between
grandparents and grandchildren, and investigated whether it might be able to support
childcare. Thus, this study answers the following questions:- What features and characteristics are required in a tele-presence robot that focuses oninteraction with babies and toddlers?
- Is a tele-presence robot for babies and toddlers socially accepted by parents andgrandparents?
- How will grandparents use a tele-presence robot for babies and toddlers in real homeenvironments?

Fig. 1 Grandmother (on the right) remotely interacts with her grandchildren through
ChiCaRo’s hand
2. RELATED WORKS
2.1 Telepresence robots
There are many tele-presence robot products in the world: Doubles by Double
Robotics, Beam/Beam+ by Suitable Technologies, QB Avatar by Anybots, Kubi by

RevolveRobotics, and so on. These robots are already being used in real environments,
such as offices, hospitals, and homes, but their target users are mainly adults, unlike ourresearch targets. Romo by Romotive is a tele-presence robot that interacts with children
using additional software, but its main purpose is to support education.
Researchers also use tele-presence robots to understand how people interact withothers and develop functions for more natural remote communications [20] [21]. For
example, Rae et al. showed that a tele-presence robot’s mobility is important forincreasing the feelings of its presence in remote users [22]. Wada et al. developed a teleoperation system that captures special knowledge from domain experts to develop arobot’s interaction contents [23]. Zheng et al. developed a tele-operation system tocontrol multiple social robots for conversation and navigation [24].
However, these research works generally focused on interaction between adults,
i.e., evaluating the functions of tele-operation or interaction with adult participants.
Even the few research works that conducted trials with a tele-presence robot and young
children addressed how children interact with robots or used education contexts foryoung children, not babies or toddlers. In this paper, we evaluate the social acceptanceand effectiveness of a tele-presence robot that is designed for interaction withbabies/toddlers through two kinds of trials involving parents and/or grandparents.

2.2 Robots for childrenChild-robot interaction is one active research topic in robotics, especiallyeducation for school-aged children. For example, Tanaka et al. developed an
educational application for Pepper (Softbank. Co. Ltd.) to learn with children [14] andproposed a care-receiving robot concept that enables children to learn by teaching therobot, instead of the robot teaching them [15]. They conducted a field trail using a child-operated telepresence robot [16] and investigated how children interacted with it
through a long-term field trial [25]. Kim et al. investigated the effectiveness ofvideoconference technology by comparing a telepresence robot and a simple video
system for children [17]. Tamura et al. developed a story telling system for children
with multiple robots [26]. Social robots have also been used as educational tools for
autistic children [27].
Interaction with babies/toddlers is another growing research topic in the humanrobot interaction research field. For example, Fink et al. developed a robotic toy box
that encourages young children to pick up their toys and investigated its effectivenessthrough a Wizard-of-OZ technique [13]. Abe et al. investigated play strategies forchildren by gathering interaction data between children and a tele-operated robot
controlled by a preschool teacher [28]. Hieida et al. investigated the effects of shaking
hands in interaction between a tele-operated robot and kindergarteners [29]. However,these research works focused on developing functions for autonomous communication
robots to interact with children, observations of child-robot relationships, orunderstanding human decision-making processes under the context of child-adultinteraction.
Unlike these research works, we focused on a tele-presence robot for interaction
with babies and toddlers for remote interaction with parents and grandparents.
Moreover, we experimentally investigated the social acceptance of our developed robots
and their effectiveness through field trials in real environments.

3. Design of a Telepresence Robot for Babies and Toddlers
What kinds of design features/characteristics are needed for a tele-presence
robot that can interact with babies and toddlers? As described in the introduction, sizeand mobility are essential for rich remote interaction. If locomotion is enabled, such
strict safety functions as an autonomous-stopping function are needed. Moreover, when
we are playing with toddlers, since we often engage in such interactions as playing
house, a tele-presence robot requires a hand-like device to expand the range of playing
options. In fact, past research with tele-presence robots realized that locomotion
capabilities and hand devices are critical for smoother interaction with young children,
even though these works weren’t focusing on babies and toddlers [16, 17].
Based on these contexts, we decided to tackle such designs based on theopinions of the actual future users, i.e., parents, not the researchers’ perspective. For
example, if the actual users disagree that mobility is needed for remote interaction,
developing such tele-presence robots is futile. We conducted a web survey of parents
and grandparents who are potential users and gathered their opinions about a telepresence robot for interacting with babies and toddlers.

3.1 Web-based survey
Our web-based survey about a tele-presence robot for interacting with babies
and toddlers investigated preferred size and whether mobility and a hand-like device areneeded for remote interaction. In addition, we investigated their preferences of thecurrent tele-operated robots for interaction. In our survey of 208 Japanese adults (52females and 52 males with preschool children and 52 females and 52 males withpreschool grandchildren, the participants answered the following items on a 1 to 7 scale,where 7 is the most positive:
1. Preferred robot size:
1-1, Taller than children (120 cm or more)
1-2, Similar to children (60~120 cm)
1-3, Shorter than children (20~60 cm)

1-4, Much shorter than children (20 cm or less)
2. Mobility for a tele-presence robot
2-1, Only rotation ability
2-2, Forward/backward and rotation abilities
3. Usefulness of a hand-like device
3-1, Only video chat function
3-2, Hand-like device for richer interaction
4. Preference of current tele-operated robots for interaction
4-1, Beam+
4-2, Romo

3.2 Results of web-based survey
Figure 2 and Table 1 show our web-based survey results. We analyzed thepreferred size with a one-factor between subjects ANOVA (Fig. 2-a) and found asignificant effect (F (3, 621) = 46.459, p < .001, partial η2 = 0.183), and a multiple
comparison with the Bonferroni method revealed significant differences: similar andshorter > taller and much shorter (p<.001). There were no significant differences
between similar and shorter, and taller and much shorter. Based on these results, wechose the size of our tele-presence robot to be between 20 cm~120 cm.
We conducted a one-factor between subjects ANOVA for the mobility of a telepresence robot (Fig. 2-b) and found a significant effect (F (1, 207) = 35.962, p < .001,
partial η2 = 0.148). The result showed that participants not only wanted a rotation
function but also a forward/backward function. Since past research also reported theimportance of a moving function for tele-presence robots in interaction with young
children [16], we implemented both functions in our robot.

We also conducted a one-factor between subjects ANOVA on the usefulness ofa hand-like device (Fig. 2-c) and identified a significant effect (F (1, 207) = 46.413, p< .001, partial η2 = 0.183). The result showed that participants believe a hand-likedevice is useful for remote interaction. Since past research work also reported that a
robot with hands encourages more interaction with young children [16], we developed ahand-like device for our robot.
Finally, we prepared two candidates from existing tele-operated robots, Beam+and Romo, both of which can interact with children (Fig. 2-d). Beam+ is about the same
size as a child, and Romo is smaller. Both robots have forward/backward and rotation
abilities and no hand-like device (to the best of our knowledge, no tele-presence robot
consumer product has both hand-like devices and moving ability). Currently, Romo’svideo chat function cannot be used because Romotive’s official services have beensuspended, but it can still see video images and select such behaviors of animatedcharacters as smiling. Therefore, it has enough capability to remotely interact withbabies and toddlers. We also conducted a one-factor between subjects ANOVA andfound a significant effect (F (1, 207) = 7.208, p = .007, partial η2 = 0.034). Participantspreferred Romo over Beam+ during their remote interaction with babies and toddlers.
We used this result for determining an alternative robot for our experiment and describe
the details in Section 5.4. We note that there is no free description form in our web
survey therefore the main reason of why the participants preferred Romo more thanBeam+ is still unknown, but we thought that the based on robot’s size. Romo isbasically designed for children, therefore its size is smaller than Beam+; therefore, even
if Romo collides children, it would not cause serious problem than Beam+ due to its
size.

7

7

6

6
***

***

7

7
*** : p < .001*** : p < .001

6***** : p < .01*** : p < .001

6

***

5

5

5

4

4

4

4

3

3

3

3

2

2

2

2

1

1

1

5

1-1

1-2

1-3

1-4

2-1

(a)

2-2

**

1

3-1

(b)

4-1

3-2

(c)

4-2

(d)

Fig. 2 Web-survey results
Table 1 Average and S.E of each item

1-1
1-2
1-3
1-4

Ave.
2.96
4.19
4.23
3.30

S.E.
0.09
0.10
0.09
0.10

2-1
2-2

Ave.
3.87
4.65

S.E.
0.08
0.09

3-1
3-2

Ave.
3.97
4.74

S.E.
0.09
0.08

4-1
4-2

Ave.
3.80
3.98

S.E.
0.08
0.09

4. ChiCaRo
Based on our web-survey results, we developed a tele-presence robot named
ChiCaRo (Fig. 3), which is 350 mm (height) x 270 mm (width) and weighs 4 kg. It has
a 7-inch LCD monitor as a head (2 DOFs) and differential wheels for movement (2DOFs). ChiCaRo has a small hand-like device (width: 103.5 mm, radius: 60 mm) on its
front that can open and shut for accepting toys from children, calling them, andattracting their attention. Six touch sensors and four infrared-based distance sensors
ensure safety, and one color sensor tracks the person with whom it is interacting.
ChiCaRo is equipped with a stick PC (MS-NH1-AMZN, MouseComputer) for video
chat, Arduino Mega and Nano for motor control and color as well as touch and distancesensor processing.
The reasons of why ChiCaRo’s size as 350mm height are mainly two kinds: thefirst reason is because the participants in the web-survey preferred 20~60cm and60~120cm and also they preferred Romo than Beam+; we thought that participantspreferred more safety size robot for babies and toodlers, therefore we designed the
ChiCaRo’s size between 20 ~ 60cm firstly. The second reason is to cope with bothenough display size and locomotion capability for ChiCaRo. Through testing with
prototype system with babies and toodlers several times, we decided this size for
ChiCaRo.

Six touch sensors(one sensor in back)
One web camera
One color sensor
Distance sensor(two sensors in back)Fig. 3 Appearance of robot and location of sensor
Camera /mic

Hand
control

Video chat

ChiCaRo
Color
sensorPeopletracking

Touch /
distance
sensors

Navigation
SafetyObjectdetection

Operator involved
Autonomous

Fig. 4 Software architecture of ChiCaRo

Fig. 5 Tele-operation user interface

4.1 Software architecture
There are three main functions involved in this study: video chat, hand-control,and navigation. Fig. 4 shows the software architecture that illustrates the relationshipamong these functions.

4.1.1 Video chat
We used Linphone, which is open-source VoIP software, as a video chatfunction for ChiCaRo. The operator uses a web camera for video chat, allowing thechildren to see the operator’s face through ChiCaRo’s monitor. Its web camera transfers
the interacting children’s faces and voices to the operator.

4.1.2 Hand-control
The operator can open/shut ChiCaRo’s hand-like device through the userinterface. As described above in the section 4, the operator uses the hand-like device toplay house, call children, and so on. Considering safety and protecting the servo motors,
the hand servo is only energized when the hand is in motion.

4.1.3 Navigation
The operator can freely navigate ChiCaRo through a user interface (described insubsection 4.2). Safety is secured by an autonomous system. The robot’s movement isautonomously stopped based on the distance between the robot and the nearest obstacle.
For instance, when obstacles exist within 300 mm in front/back of the robot, or touch
sensors detect physical contact with the robot, it is immediately stopped. We limited therobot’s speed to 300 mm/sec in the experiment.
ChiCaRo also has a function for following a target child. The color sensor
recognizes color pixels based on pre-registered information and calculates theorientation of the gravity point in the sensor image to follow a target child. The operator
can select whether to use this function through a user interface.

4.2 Tele-operation user interface
Figure 5 shows a user interface for tele-operation. The primary information
sources are images from ChiCaRo’s camera (left panel in Fig. 5) and sounds from its
microphone. The operator can navigate and control its hand behaviors throughcontroller buttons (right panel in Fig. 5).

5 Experiment
We experimentally investigated the social acceptance and usefulness of ourdeveloped robot in a play room environment. We note that investigating each feature in
WEB-survey would be useful to understand the effectiveness of them, however such bottom-up
approach has difficulties in reality because of the number of features and combination effects
between them. In particular human-robot interaction is multi-modal, therefore it would be
difficult to clearly find the effectiveness of each feature. Therefore, we compared theeffectiveness of ChiCaRo by directly comparing with an alternative robot in this study.

5.1 Hypothesis and prediction
Even though various tele-presence robots or robotic toy systems exist, they
focus less on remote interaction with babies and toddlers. Hence, we developed aprototype of a tele-presence robot, ChiCaRo, for interacting with them based on
opinions gathered by web-surveys. We expect that people will evaluate ChiCaRo more
highly when they are remotely interacting with their children than existing robot
systems from both social acceptance and usefulness viewpoints.
Prediction: People will more positively evaluate ChiCaRo’s interaction ability
with their children than existing tele-operated robots.

5.2 Participants
In our experiments, 36 people (17 adults and 19 children whose ages ranged
from zero to three) participated. Some families participated together (cumulative total
number is 41, 17 adults and 24 children). Adult participants were paid 4,000 yen (about
36 dollars, including transportation expenses). 17 adult participants (13 women and fourmen), comprised of four grandparents and 13 parents, answered questionnaires.

5.3 Environment
Figure 6 (left) shows the experiment environment. The room was about 40 m2,
big enough to accommodate more than ten people (five adults and five children). We
installed two web cameras for recording and showing images to the operator. Toys,
books, and chairs are available in the room for the participants.

Fig. 6 Experiment environment and Romo

5.4 Conditions
The study had with a within-participants design with the following two
conditions:
ChiCaRo condition: In this condition, the adult participants used ChiCaRo toremotely interact with their children. Before starting this condition, they moved to an
operation space. The maximum experiment time was ten minutes, but if the children
were scared by the robot, the session was immediately ended.

Alternative condition: Following the web-survey results (Section 3.2), in thiscondition, adult participants used Romo (Fig. 6, right) to remotely interact with theirchildren. We controlled it with an iPod Touch and official software that enables theadult participants to see the video image from Romo, navigate it, and select various
behaviors of animated characters. Before starting this condition, they also moved to an
operation space. The maximum experiment time was 10 minutes, but if the children
were scared, the session was immediately ended, as in the ChiCaRo condition.

5.5 Procedures
In the experiment, we asked participants to act freely in the environment for twohours. In the first hour, the children became acclimated, and the adults learned about the
ChiCaRo and Romo tele-operation systems.
In the second hour, the adult participants controlled ChiCaRo or Romo andinteracted with their children. After the tele-operation of either robot, they controlled
the other robot and again interacted with their children for five minutes and answeredquestionnaires after controlling both robots. The order of manipulating the teleoperation robot was counterbalanced. If multiple adult participants were present, we
asked each of them to control each robot sequentially. To avoid combination effects ofmultiple robots, only one robot was used at a time.

5.6 Measurements
We investigated two measurements by questionnaires on a 1 to 7 scale (7 is mostpositive): intention to use and usefulness. We measured the former because in studies of
the acceptance of new technologies [29] and social robots [3, 30], it is modeled andindicates social acceptance. This scale consists of three items that were adapted from
Heerink et al. [31], including, “I’m planning to use this robot in the next few days.”Note that the Cronbach’s alpha statistics [32] of intention to use were 0.873 and 0.948
in the ChiCaRo and Romo conditions, which are within a good range. We measured
usefulness by a single item, “I think that ChiCaRo will be useful for remote interaction
with children and grandchildren,” to investigate whether they felt the robot was usefulfor interaction.

5.7 Results
5.7.1 Verification of prediction
Figure 7 and Table 2 show the questionnaire results for intention to use (ITU)
and usefulness. For intention to use, we conducted a paired t-test and identified asignificant main effect between conditions (t (16)=5.533, p<.01, r=0.81). This meansthat the adult participants evaluated ChiCaRo’s intention to use higher than Romo.
For usefulness, we conducted a paired t-test and identified a significant main
effect between conditions (t (16)=5.636, p<.01, r=0.82). The adult participantsevaluated ChiCaRo’s usefulness higher than Romo. Thus, our prediction was supported.
7

**

**

ITU

Usefulness

6
5

4
3

2
1
Alternative

ChiCaRo ** : p < .01

Fig. 7 Questionnaire results
Table 2 Average and S.E. of the questionnaire results
ITU
Alternative
ChiCaRo

Ave.
3.556
4.778

S.E.
0.411
0.358

Usefulness
Ave.
S.E.
4.583
0.336
5.833
0.297

5.7.2 Observations of interaction with robots
In both conditions, the typical interaction pattern was that the children looked at
the robot and chatted with the operator by ChiCaRo or played with Romo. In the
ChiCaRo condition, first, the adult participants greeted their children by ChiCaRo andasked if they wanted to play. Several adult participants asked their children to put toys
in ChiCaRo’s hand to play with them. When children moved around to find appropriate
toys to hand over, the operators navigated ChiCaRo to follow the children. Fig. 8 showsa typical interaction scene between ChiCaRo and a child:
Operator (grandmother): “What’s that?”
Boy: “A ball” (he puts a yellow ball in ChiCaRo’s hand).
Operator: “Please show me more balls.”
Boy: “Okay” (he hands over three balls).
He repeated such interactions several times and talked with his grandmotherthrough ChiCaRo. After a few minutes of interaction with it, he left and started to playby himself, and then his younger sister approached and started to play with it (Fig. 9,left). She gave a pumpkin-like toy to it, and her grandmother said thank you. When theboy noticed their interaction, he stopped playing by himself and joined ChiCaRo and his
sister. He put several food-like toys on a dish and showed them to his grandmother (Fig.
9, right).
In the alternative condition, adult participants typically navigated Romo in frontof their children and changed its behaviors to attract them. Fig.10 is an example of suchan alternative condition with a child. A mother controlled Romo to approach her son
who actively interacted with it, e.g., touching and following it. Some children
repeatedly asked, “where is the robot?” if they couldn’t catch Romo. After theexperiment ended, a mother explained to her son that she had been controlling Romo.
“Why don't you control Romo some more and play with me?” he asked.

Fig. 8 Boy interacting with ChiCaRo controlled by grandmotherFig. 9 Boy and his little sister interacting with ChiCaRo

Fig. 10 Boy interacting with Romo

5.7.3 The acceptance degree
In this section, we investigated children’s acceptance degree toward each robot
because we are interested in such acceptance degree and typical interaction patterns ofchildren, it would provide interesting knowledge to install childcare support robots inreal environments. For this purpose, we investigated whether children rejected eachrobot at the end of each session. If a child enjoyed his/her interaction with the robot or
the parents thought their child had fun, we described this child as accepted. On the other
hand, if a child did not want to interact with the robot, exhibited hesitation or fleeing
behaviors, we described this child as rejected. Therefore, we compared the number of
accepted/rejected children between ChiCaRo and Romo in the experiment.
Figure 11 shows the numbers of rejections for each robot. We verified thedifferences of the rejections among the two kinds of robots with a Chi-square test thatrevealed significant trend among the conditions (χ2 (1) = 2.923, p=.087, Cramer's V=.277). Therefore, children relatively accepted ChiCaRo compared to Romo, but thedifference is not significant. Below, we investigated the detail behaviors of children.
Romo: In the experiment, eight children rejected Romo, and the other 11
accepted and played with it. The ages of the five girls and three boys who rejected it
ranged from one to three (average: 2.38). The age of the seven girls and four boys who
accepted it ranged from one to six (average: 2.82).
We identified three typical interactions of the children who accepted Romo:
following, touching, and grabbing. The operators often tried to make Romo approachthe children (Fig. 12, left). When they noticed that Romo was approaching, they also
approached it (Fig. 12, middle), touched it, and grabbed it (Fig. 12, right).
The typical behaviors of the children who rejected Romo were running away,
returning to their parents, or hiding in the ball area. For example, one boy fled an
approaching Romo, which was being controlled by his older sister (Fig. 13, left).
Another girl entered the ball area and hid from Romo while surreptitiously spying on it(Fig. 13, right). The children who rejected Romo seemed afraid of it from the very startof their interaction with it. When Romo started to move, they immediately fled. Even if
the operators changed Romo’s face animations or had the robot retreat, the children
refused to interact with it.
ChiCaRo: In the experiment, four children rejected interaction with ChiCaRo,and the remaining 15 children accepted and played with it. The ages of the two girls andtwo boys who rejected it ranged from two to three (average: 2.50). The ages of the ten
girls and five boys who accepted it ranged from one to six (average: 2.67).
We identified two typical interactions of the children who accepted ChiCaRo:chatting and playing. Operators tried to make ChiCaRo approach the children to chatand play. The operators said the children’s name while approaching and the children
quickly noticed ChiCaRo and their parent’s face on its screen. After approaching, theoperators asked the children what they were doing or requested to see their toys (Fig.
14, left). Some children incorporated ChiCaRo into their play, such as playing housewith toy food (Fig. 14, middle and right).
The typical behaviors of the children who rejected ChiCaRo were running away,
returning to their parents (Fig. 15), or explicitly demanding that it stay away. For
example, when one girl was scared by ChiCaRo, which was being controlled by a friendof her father, she asked her father to pick her up. Another boy aggressively rejected
ChiCaRo, pointed at it, when it was being controlled by his mother, and commanded:“Don’t move!” (Fig. 16).

16
14
12
10
8
6
4
2
0
RejectedRomo

Accepted
ChiCaRo

Fig. 11 The number of children in each category

Fig. 12 Children who interacted with Romo

Fig. 13 Children who rejected Romo

Fig. 14 Children who interacted with ChiCaRoFig. 15 Girl rejected interaction with robots
Don’t
move!

Fig. 16 Boy who rejected ChiCaRo
5.7.4 Observation of interaction with ChiCaRo’s hand
We investigated the interaction between ChiCaRo and children by focusing on ause of the robot’s hand. For this purpose, we counted the number of children who
played with ChiCaRo through its hand. As a result, all children who accepted ChiCaRo(i.e., 15 children) played with their parents through its hand. Similar to past studies [16,17], ChiCaRo’s hand encourages smoother interaction between parents and theirchildren. For example, typically they used the hand to hand-over toys or receive themfrom ChiCaRo. Such interaction often happen in usual interaction between them while
they are playing with. Moreover, some of parents used ChiCaRo’s hand to attract
attentions of children, e.g., waving its hand around their children and saying theirnames. Therefore, ChiCaRo’s hand enables different kinds of physical interaction
compared to locomotion capabilities, which contributed to realize richer interaction
between parents and children through ChiCaRo.

5.7.5 Interview results
As reported in Section 5.7.1, the ChiCaRo condition resulted in better social
acceptance and higher usefulness. We specifically asked the participants about theirreactions in interviews at the end of the experiments.
Seven adult participants positively evaluated ChiCaRo’s locomotion abilities.
For example, a grandmother said, “The moving function is good because it can follow a
crawling baby, which is different from a video chat.” She often used video chat with her
grandchild. Another grandmother praised ChiCaRo’s hand-like device: “its hand isuseful for playing with children because it can give them different toys.” She often
played house through ChiCaRo with her grandchildren. Another participant believedthat ChiCaRo might be used for childcare and watching children.
During the interviews, a few negative comments surfaced. One participant
expressed safety concerns if the robot were to suddenly malfunction. Because
ChiCaRo’s purpose is to interact with babies and toddlers, she was worried that a
broken robot might injure her son. Two adult participants thought the robot’s noise
might frighten babies.

6 Field trial
Next, we conducted a field trial to investigate the effectiveness of the developed
robot in real home environments.

6.1 Procedure
This field trial involved three nuclear families including preschool children andgrandparents. Three grandchildren (two boys and one girl whose average age was 3.03
years) and four grandparents (three grandmothers and one grandfather whose ages
ranged from 55 to 64) participated in our field trial. In these three families, thefrequencies of the face-to-face interactions between the grandparents and the
grandchildren were once a year, three times a month, and once every three months.

Each family freely used ChiCaRo over five or six days in their homes. The
operators were grandparents who are living far away from them. On the first day, we
installed ChiCaRo in their living rooms and explained how to use it to both parents andgrandparents. At the end of the experiment, we interviewed both parents andgrandparents to gather their impressions of ChiCaRo.

6.2 Results
During the field trial, the families used ChiCaRo an average of 2.63 times perday, and the average length of the time was 26.0 minutes per day. The operators mainly
used ChiCaRo to play with their grandchildren, e.g., chasing them with ChiCaRo,looking at the children dancing around, watching TV together, and so on (Fig. 17); theyalso greeted their grandchildren with ChiCaRo or just talked.
Sometimes they watched the children’s daily activities using ChiCaRo’s
locomotion ability. Different from video chats, the operators can follow children by
ChiCaRo even if they are moving around. In fact, the operators reported that ChiCaRo’s
locomotion capabilities enabled longer conversations than video chat. Moreover, ininterviews, mothers believed they benefited because grandparents watched their
grandchildren through ChiCaRo during periods when the simultaneous burdens of
cooking, meal preparation, and childcare overlapped. During the field trials, ChiCaRo
assumed some of the childcare responsibilities of the parents.
All four grandparent operators positively evaluated ChiCaRo and expressed adesire to use it again because it increased opportunities to interact with their
grandchildren as well as their own adult children. Three operators praised ChiCaRo’s
moving functions for interaction with their families.

The operators admitted that their daily activities were positively changed byusing ChiCaRo. In an interview, one operator said, “We shared our daily life through
ChiCaRo. My grandchild greeted me in the morning and at night, and so I could easily
learn about his activities.” Another operator reported positive opinions, such as,“Interacting with my grandchild is really fun. When I knew that I was going to use
ChiCaRo, I had a reason to tend to my appearance. Since I’m usually alone, I often
neglect myself.”
Even though we conducted field trials with the families for only about a week,
all three families positively evaluated it. Using such tele-presence robots increased
interaction opportunities and provided merits to both parents and grandparents.
Interaction with grandchildren through tele-presence robots might strengthen the social
bonds among family members.

Fig. 17 ChiCaRo in a home environment

7 Discussion
7.1 Implication and applications
One immediate design implication is that remote interaction with babies andtoddlers is improved when it contains physical interaction. In reality, such interaction
increases cost considerations because locomotion and hand-like device capability are
more expensive than a simple video chat. We believe that robots for this purpose will beexpected to have multiple functions, e.g., partial autonomous playing with children andwatching them when an operator cannot briefly control the robot with a semiautonomous robot approach [30]. For such purposes, a tele-presence robot that isdesigned for interacting with toddlers might be financially beneficial because it
outperforms a simple pan-tilt type web-camera.

7.2 Future work
We thought that there are two kinds of future works exist: increasing autonomy
based on tele-operation histories by professional childcare workers and a use of virtual
agent.
About the increasing autonomy, we thought that operation and interaction
histories by professional childcare workers would help this purpose. Because for people
who do not have much experiences of interaction with babies and toddlers, even if theycan easily operate ChiCaRo, they cannot interact well with the babies and toddlers. In
such situation, if the system autonomously recommend appropriate play behaviors for
operators based on sensing data, it will encourage more natural interaction between
them. Already several past studies tried to develop autonomous system by using
operation and interaction histories between semi-autonomous robots and people [23][30], such knowledge would be useful to increase autonomy of ChiCaRo.
Of course, for this purpose, integration of several sensing system would be
important to understand behaviors of the babies and toddlers and environmental
situations. For this purpose, a use of environmental sensing system [31] [32] would be
one possible approach to realize rich sensing capabilities for ChiCaRo. For example,
past studies realized to estimate the interaction behaviors by using acceleration sensors
in a small robot [33]; if we can distribute several toys including such sensors, thesystem could understand how children play with toys and use its information forinteraction between ChiCaRo and them. Moreover, integration with wearable sensors
and environmental human tracking system enables identification of people in theenvironment; such identification system also helps operation of ChiCaRo, in particularat crowded environments.
About the use of a virtual agent, it would be useful when an operator is non
family member of children, e.g., childcare worker. If children find unknown people at
ChiCaRo's display, they would be cautious about interacting with it; but if a virtual
agent is shown in the display of ChiCaRo interaction with children is easier for thesepeople. Also, a use of a virtual agent enables multiple people to interact with children
via ChiCaRo anonymously, it might be useful for a use of ChiCaRo at nursery schools.

7.3 Limitations
This research work has several limitations. In our experiment, the adultparticipants interacted with their children for limited time periods. Also, open questions
remains: How will their feelings toward ChiCaRo and Romo change in time and withmore frequent exposure? How will the children change their interaction style toward
ChiCaRo and Romo? Moreover, ChiCaRo’s appearance is essential for changing theimpressions of children; its design can be modified through surveys from real users. We
only tested two kinds of robots based on the web-survey results due to the number of
combinations of each feature, therefore we did not clearly investigate each featureeffects, and other possible features such as a colour or interaction distance are notinvestigated yet.
Moreover, at the experimental comparison between ChiCaRo and Romo, we
could not use video chat function of Romo due to suspension of services by the Romo’s

company. There is no commercial robots with similar size and locomotion capability,
therefore we decided to use Romo in this study even if the video chat function was
suspended; but it would make another limitations, because children might be attracted tovideo chat with their parents.
In this study, all operators are familiar members towards children. If an operator
is an outsider for children, they would be cautious about interaction with ChiCaRo.
Children would need a time to be acclimatized to such unknown persons. But, different
to adult people, their curiosity often exceed their cautiousness. Thus, we thought that if
the operator would have enough knowledge to attract children’s attentions e.g.,childcare worker, they will be able to interact with children well via ChiCaRo. In fact,
past studies already showed that children can interact with a tele-operated robot whichis controlled by childcare workers [28] [34]. Related to this topic, a use of virtual agent
is one possible approach to decrease children’s cautiousness, as described in the above
section.
However, despite several limitations we believe this research work provides
valuable knowledge for robotics researchers who are targeting child-robot interaction.

8 Conclusion
This paper presents a tele-presence robot, ChiCaRo, which is designed forremotely interacting with babies and toddlers to increase interaction opportunities
between grandparents and grandchildren. We implemented video chat, navigation,
safety measures, and a hand-like device for rich remote interaction between operatorsand babies/toddlers and to support operations through autonomous functions.
First, we conducted an experiment in a playroom to investigate ChiCaRo’s
social acceptance. We addressed intention to use and ChiCaRo’s usefulness andcompared it to an existing robotic toy that can also be controlled by operators. In our
result, adult participants preferred ChiCaRo and children relatively accepted ChiCaRo
compared to the existing robotics toy.
We also conducted a field trial in real home environments with three nuclear
families and their grandparents to investigate the effectiveness of ChiCaRo. During oneweek trials, grandparents effectively interacted with their grandchildren through
ChiCaRo. Interaction through ChiCaRo also decreased the burden of mothers who werepreparing meals and/or cooking by assuming the responsibility of watching children.
We believe that our findings will lead to the development of tele-presence robots forbabies and toddlers.

Acknowledgements
We thank the children and their parents/grandparents for their participation. This
research work was supported by JSPS KAKENHI Grant Numbers JP15H05322 andJP16K12505, and Grant-in-Aid for JSPS Fellows JP15J11597 and JP17J40236.

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