International Journal of Humanoid Robotics
Vol. 17, No. 5 (2020) 2050019 (33 pages)c World Scienti¯c Publishing Company°
DOI: 10.1142/S021984362050019X

TELESAR VI: Telexistence Surrogate Anthropomorphic
Robot VI

Susumu Tachi*, Yasuyuki Inoue† and Fumihiro Kato‡
Institute of Gerontology, The University of Tokyo
7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan*tachi@tachilab.org†y-inoue@tachilab.org‡
fumihiro.kato@tachilab.org
Received 7 June 2020
Accepted 13 July 2020
Published 31 October 2020
Telexistence refers to the general technology that allows humans to experience the real-time
sensation of being in another place, interacting with a remote environment, which may be real,virtual, or a combination of both. It also refers to an advanced type of teleoperation system thatallows an operator behind the controls to perform remote tasks dexterously with the feeling of
being in a surrogate robot working in a remote environment. Telexistence in a real environment
through a virtual environment is also possible. The concept was originally proposed by the ¯rst
author in 1980, and its feasibility has been demonstrated through the construction of alter-ego
robot systems called Telexistence Surrogate Anthropomorphic Robot (TELESAR) I–V. TELESAR VI is a newly developed telexistence platform for the ACCEL Embodied Media Project.
It was designed and implemented with a mechanically unconstrained full-body master cockpit
and a 67 degree of freedom (DOF) anthropomorphic avatar robot. The avatar robot can operate
in a sitting position since the main area of operation is intended to be manipulation andgestural. The system provides a full-body experience of our extended \body schema," whichallows users to maintain an up-to-date representation in space of the positions of their di®erent
body parts, including their head, torso, arms, hands, and legs. All ten ¯ngers of the avatar robot
are equipped with force, vibration, and temperature sensors and can faithfully transmit theseelements of haptic information. Thus, the combined use of the robot and audiovisual information actualizes the remote sense of existence, as if the users physically existed there, with theavatar robot serving as their new body. With this experience, users can perform tasks dexterously and feel the robot's body as their own, which provides the most simple and fundamental
experience of a remote existence.
Keywords: Telexistence; telepresence; teleoperation; master-slave system; haptic primary colors;
embodied media.

1. Introduction
Telexistence is a neologism coined by combining the pre¯x \tele" and the word
\existence." It is a concept that denotes an extension of human existence, wherein a*Corresponding author.

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S. Tachi, Y. Inoue & F. Kato

person exists wholly in a location, other than his or her actual current location, andcan perform tasks freely there. The term also refers to the system of science andtechnology that enables realization of the concept.
The notion of telexistence1 was conceptualized in September 1980 in Japan,2 anda patent was ¯led for it.3 The ¯rst visual telexistence device was developed in Japan4
where its experimental results were presented; subsequently, the ¯ndings were presented at an international conference.5 Experiments have been conducted using amobile telexistence system,6 telexistence surrogate anthropomorphic robot (TELESAR),7 an anthropomorphic telexistence robot system, and a bipedal robot,8 and its
feasibility and utility have been demonstrated.
The idea of mutual telexistence, which provides both the sense of presence and thesense of self-presence was presented in 1999,9 and a mutual telexistence visual system
based on the retro-re°ective projection technology (RPT) was tested.10 In the 2005
Aichi World Exposition, TELESAR II,11 an anthropomorphic mutual telexistence
robot system was constructed, and the feasibility and utility of mutual telexistence
were demonstrated through an open experiment.
With the goal of unraveling self-recognition and self-existence, TELESAR III, atelexistence master-slave system that can interact with humans with ease, wasconstructed, and assessment experiments that centered around the extension of bodyand self-recognition were performed.12
In the subsequent TELESAR IV system, VORTEX, an omnidirectional stereo
camera, was mounted on a surrogate omnidirectional mobile robot with an arm and ahand, and was used to conduct a test demonstration for people to remotely participate in an event. Using TWISTER,13 the remote participant can, with no special
glasses, observe the 360  panoramic, full-color, real-time, stereo image sent fromVORTEX, hear sounds from all directions, and communicate with local participantsat the event hall with gestures and the sense of presence. Furthermore, the local
participants at the event hall can have regular conversations and even watch fromtheir preferred angle, the image of the remote participant, captured from thecameras set up such that they rotate outside TWISTER, as projected onto the robot
through the RPT. The on-site local participant can even shake hands with theremote participant and have the sense of presence of the remote participant.14 The
above mentioned system demonstrated the feasibility and utility of telexistence withregard to the visual and auditory senses. To further convey the sense of touch(somatosensory perception), TELESAR V was built.15 The sense of touch can bedivided into proprioceptive and cutaneous sensations. The feasibility and utilityof proprioception, another name for kinesthesia, had been demonstrated inteleoperation prior to telexistence through force-feedback bilateral control and impedance control.
In TELESAR V, we sought to implement haptic telexistence, which primarily
conveys cutaneous sensations, as well as \the sense of smoothness," \the sense ofroughness," and \the sense of warmth," together with proprioception, by actively
exploring the environment. A remotely located slave robot tracks the movement of a
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TELESAR VI: Telexistence Surrogate Anthropomorphic Robot VI

person, and the visual ¯eld and sound captured by the eyes and ears of the robot
mounted on the head of the slave are presented realistically to the person through themaster's visuo-auditory presentation system. Moreover, the arms and hands of theslave track the movement of a person's arms and hands, and make contact with atarget object. This allows the person to obtain haptic information that does notcontradict the visual and auditory information of the object and to have the feeling of
being present at the location of the robot despite being in a remote place. Thus, itenables, albeit limitedly, the person to \touch things as they look." However, thedegree of freedom (DOF) of the robot's body is limited, compared to the humanbody. Further, haptic information is transmitted only via three ¯ngers, and the senseof touch that can be transmitted is also limited; thus, a telexistence platform that ismore akin to the human body has been called for.
The author and his colleagues have been promoting early development of products and services based on the recording, transmission, and replay of somatic experience using the sense of touch, by developing a small, integrated haptictransmission module and providing it widely to industry sectors as well as generalusers. This module is based on the principle of haptic primary colors in the JST
ACCEL Project (Embodied Media Project)16 entitled \development and applicationof embodied media technology based on haptic primary colors."
As part of this project, TELESAR VI, a telexistence avatar system was developed
as a successor to TELESAR V. It has 67 DOFs, which is close to that of humans, andconveys the tactile sensations of all ten ¯ngers, based on the principle of haptic
primary colors. In this paper, the system con¯guration and the system operation are
described.

2. An Overview of TELESAR VI
TELESAR VI, the telexistence robot system developed in this study, is an avatar
robot system developed as an embodied telexistence platform in the aforementioned
Embodied Media Project. As a self-incarnation (avatar), it enables a person to
perform various actions ranging from watching and listening to speaking, from aremote location, as if he/she were physically present.
In recent years, remote communications and remotely controlled robots have beenused in various situations, including telecommunications, disaster relief, and medicalcare. To operate these robots safely and freely as incarnations of the operators, anenhanced sense of presence, as if the operator him/herself were physically present at
the remote location of the robot, is critical. The ¯rst author proposed the concept oftelexistence as far back as 1980; he has, since then, designed and promoted various
projects for the research and development of technologies that facilitate an increased
sense of presence. Recently, a global competition, the ANA AVATAR XPRIZE, wasinaugurated for the actualization of telexistence, creating a powerful trend for its
commercialization.

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S. Tachi, Y. Inoue & F. KatoTELESAR VI is a successor to TELESAR V, which played a major role in theselection of avatar as the next theme of XPRIZE.17 One feature of TELESAR VI isthat it realizes 67 DOFs, an unparalleled feat in the world of telexistence robots. As
an index evaluating the extent to which the body can freely move, DOF, which
represents the number of joints that can be independently controlled, is used.
TELESAR V had 53 DOFs; in TELESAR VI, on the other hand, we successfullyincreased it to as much as 67. In the past, there were 64- and 114-DOF humanoid
robots.18 However, they did not permit telexistence. In TELESAR VI, telexistence
was realized by controlling the 67 DOFs of an avatar robot concurrently with theunconstrained measurements of 134 DOFs of humans, together with the transmission of the realistic sense of vision and hearing.
The 67 DOFs can be broken down as follows: three in the head, six in the torso,
seven for each arm, six for each leg, and 16 for each hand. With the avatar robot
having almost as many DOFs as human beings, human-like actions can be naturally
conveyed to it. Further, having legs that can move at one's disposal largely increases
the sense of possession of a body, enabling operators to experience their new robotic
body more vividly. The avatar robot can operate in a sitting position since the mainarea of operation is intended to be manipulation and gestural.
Figures 1 and 2 show the con¯guration and the general view of the TELESAR VI
system, respectively. This system is a master-slave system consisting of a\visuoauditory information system," where visuoauditory information is measured,transmitted, and presented in real-time to the operator; the \movement measurement and control system," where the operator's movement is measured and transmitted in real-time to control the robot such that its movement tracks that ofFig. 1. System diagram of TELESAR VI.

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TELESAR VI: Telexistence Surrogate Anthropomorphic Robot VI

Fig. 2. TELESAR VI master slave system.

the operator, and the \haptic information system," where haptic information ismeasured, transmitted, and presented to the operator in real-time. The details of the
TELESAR VI system are described in Secs. 3–4.
3. Mechanical Speci¯cations of TELESAR VI
3.1. Overall configuration
As brie°y described in Sec. 2, the mechanism of TELESAR VI consists of several bodyparts: a main body consisting of 6DOF torso and 3DOF head, a pair of 7DOF arms
attached to the shoulder of the main body, a pair of 6DOF legs attached to the bottomof the main body, and a pair of 16DOF hands attached to the top of the arm.
The joints in the mechanism are equipped with high-power DC micromotors(FAULHABER Drive Systems) and have a wide movable range, su±cient to replicate
the human body movement. The details of each part are described in Secs. 3.2–3.5.
3.2. 6DOF torso and 3DOF head
Figure 3 shows the outline of the main robot body consisting of 6DOF torso and
3DOF head, and Table 1 shows the speci¯cations. The hip is equipped with a
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S. Tachi, Y. Inoue & F. Kato

Fig. 3. Outline drawing of the main robot body.

Table 1. Speci¯cations of the body joints.
Mechanical limit
Joint

Negative

Positive

Function

JB1
JB2
JB3
JB4
JB5
JB6
JB7
JB8
JB9

20 
10 
90 
1 mm
27 
17 
31 
31 
62 

þ20 
þ36 
þ90 
þ101 mm
þ9 
þ17 
þ31 
þ46 
þ62 

Hip X-Rot
Hip Y -Rot
Hip Z -Rot
Spine Z -Tran
Chest Y -Rot
Chest X-Rot
Neck X-Rot
Neck Y -Rot
Neck Z -Rot

lightweight parallel actuator to drive its joints (JB1 and JB2) to achieve quick body
movements. In addition, the spine is equipped with a linear actuator to move thebody vertically to maintain head height against body sway. If the rotation mechanism is applied to the vertical adjustment, the torso would spread out horizontallywhen it was lowered. By using the linear actuator in the spine, the body structure of
the torso becomes closer to actual human body.
3.3. 7DOF arms
Figure 4 shows the outline of the 7DOF robot arm, and Table 2 shows the speci¯cations. The size, motion range, and DOF con¯guration of the robot arm are the2050019-6

TELESAR VI: Telexistence Surrogate Anthropomorphic Robot VI

Fig. 4.

Outline drawing of the robot arm.

Table 2.

Speci¯cations of the arm joints.
Mechanical limit

Joint

Negative

Positive

Function

JA1
JA2
JA3
JA4
JA5
JA6
JA7

40 
105 
152 
135 
93 
15 
45 

þ120 
þ21 
þ32 
þ2 
þ93 
þ45 
þ60 

Shoulder Y -Rot
Shoulder Z -Rot
Shoulder X-Rot
Elbow Y -Rot
Wrist X-Rot
Wrist Y -Rot
Wrist Z -Rotsame as those of an actual human body. The maximum payload of 1 kgf is achieved
using the lightweight robot mechanism, which weighs approximately 2 kgf.
3.4. 6DOF legs
Figure 5 shows the outline of the 6DOF robot leg, and Table 3 shows the speci¯cations. As with the arm, the size, motion range, and DOF con¯guration of the robot
leg are similar to those of a human body. Although the legs cannot support the upper
body and cannot be used to walk, they, however, possess motor abilities like knee
raising at 60 deg/s and kicking at 180 deg/s, thereby reproducing the natural leg
motion of a human sitting on the chair.
3.5. 16DOF hands
Figure 6 shows the outline of the 16DOF robot hand, Fig. 7 shows the kinematicalarrangement of the ¯nger joints, and Table 4 shows the speci¯cations. The joint
arrangements of the four ¯ngers (II–V) are common, and thumb (I) only have different arrangement. According to the movability, each ¯nger is assigned di®erent
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S. Tachi, Y. Inoue & F. Kato

Fig. 5. Outline drawing of the robot leg.

Table 3. Speci¯cations of the leg joints.
Mechanical limit
Joint

Negative

Positive

Function

JL1
JL2
JL3
JL4
JL5
JL6

8 

25 
25 
0
15 
25 

þ8 

Thigh Z -Rot
Thigh Y -Rot
Thigh X-Rot
Knee Y -Rot
Ankle X-Rot
Ankle Y -Rot

Fig. 6.

Outline drawing of the robot hand.

þ5 
þ60 
þ115 
þ15 
þ25 

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TELESAR VI: Telexistence Surrogate Anthropomorphic Robot VI

Fig. 7. Kinematical arrangement of the ¯nger joints.

Table 4. Speci¯cations of the thumb and ¯nger joints.
Mechanical limit
Joint

Negative

Positive

Function

JT1
JT2
JT3
JT4
JT5

120 
60 
0
0
30 

0
0
þ45 
þ112 
þ15 

Thumb (meta.) X-Rot
Thumb (meta) Y -Rot
Thumb (meta.) X-Rot
Thumb (prox.) Y -Rot
Thumb (dist.) Y -Rot

Abduction (JF1)
JF2
JF3
JF4

0
0
0
30 

13  30 þ15 
þ112 
þ15 

Finger (prox.) Y -Rot
Finger (prox.) Z -Rot
Finger (mid.) Z -Rot
Finger (dist.) Z -Rot

DOFs (thumb (I): 5, index (II): 3, middle (III): 3, ring (IV): 2, little(V): 2). The
thumb has a wide range of motion, and its tip can be directed to the other ¯ngers.
This is incorporated to realize ¯nger opposition, which is the main feature of humanhand. In addition, the directions of index, ring, and little ¯ngers can be changed
simultaneously using an abduction joint.
4. Master-Slave Control System of TELESAR VI
4.1. Control principle of telexistence robot
To realize the telexistence robot, the master-slave control system must be endowedwith certain functions to achieve a sensori-motor consistency between the human

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operator and surrogate robot. According to previous studies regarding telexistence,19
it is important to keep the operator's eye-to-arm endpoint vector equal to that of therobot so that the operator can always see the robot's end e®ectors such as hand and¯ngers like as his/her own body. These conditions are formularized by the following
two equations:ww
sl eye T ¼ ms eye T;
sl eyems eyesl endpoint T ¼ ms endpoint T;

ð1Þ
ð2Þ

where AB T is a 4  4 homogeneous transform matrix, which describes the position
and rotation of frame B relative to A. Equation (1) exactly tracks the head motion,
whereas Eq. (2) ensures the consistency of position and attitude of end e®ectors
observed from the camera view. Based on this formulation, the kinematic equations
are derived to realize the master–slave correspondence of each body-part. Detailed
expressions are shown in Sec. 4.2.
4.2. Motion generation of slave robot
4.2.1. Torso and head control
As aforementioned, it is crucial to reproduce the operator's head motion onto the robot's
head to realize the telexistence. This is because the operator of telexistence robot
observes the point-of-view (POV) image shot from robot's eye camera. Therefore, 6DOF
head tracking is necessary to provide an immersive experience to the operator.
Based on Eq. (1), the kinematic equations of the robot's main body can be derived
and solved to realize the head tracking. The right-hand side of Eq. (1) can be determined by measuring the operator's head position and attitude, whereas the lefthand side can be expanded by calculating the forward kinematics of TELESAR VI.
However, the expressions on the left-hand side contain nine kinematic parameters
because of 9DOF even though the head position and attitude are ful¯lled by 6DOF.
Therefore, additional constraints regarding operator's body motion are necessary toobtain a unique solution of the head tracking. As the additional constraint, theattitudes of operator's shoulders are used in order to match upper-body's posture.
4.2.2. Arm and leg control
Another major requirement of telexistence is to place the robot's end e®ector at thelocation where operator's corresponding body-part exists relative to the POV. This isbecause the operator should be able to see the end e®ector instead of his/her own
body-part at the location where the actual part exists to maintain the visuo-somatosensory consistency regarding the body awareness. Therefore, arm and leg
control must be performed only after achieving torso and head control.
For the 7DOF arm, the kinematic equations are derived from Eq. (2), and theseare solved to set the end e®ector (i.e., hand) at the position and attitude same as
those of the operator. However, an additional constraint is required to determine the2050019-10

TELESAR VI: Telexistence Surrogate Anthropomorphic Robot VI

seven parameters of arm kinematics. To solve this, the attitude of operator's upperarm is used for the constraint, such that the rotation axes of elbow joints become
parallel between operator and robot.
In addition, the kinematic equations of the 6DOF leg are derived in a manner
similar to those of the arm, and they can be solved using the operator's toe position
and attitude. In the case of leg, additional constraint is not required because thenumber of kinematic parameters is equivalent to 6DOF.
4.2.3. Thumb and ¯nger control
Similar to the arm and leg, the ¯ngers of the robot hand are controlled based on
Eq. (2) to maintain the same eye-to-endpoint vector. However, although Eq. (2)should be satis¯ed for all ¯ngers, it is quite di±cult to obtain an ideal matching
because the anthropomorphic robot ¯nger has only 2–5DOF while a 6DOF is required for each ¯nger to completely satisfy the equation. In addition, even if someelaborate robotic ¯nger had more than 6DOF, the ¯nger length di®erence between
operator and robot leads to di®erent hand postures. Therefore, it is necessary tocompromise certain factors.
Considering that the thumb plays a crucial role in hand manipulation and is the most°exible among the ¯ve ¯ngers, the position and direction of robot's thumb tip must be
controlled with high accuracy. In contrast, assuming that the reproduction of ¯nger
opposition is achieved only by the positional matching of the ¯ngertips, the other four
opposite ¯ngers have to simply follow the positions of the endpoints of operator's ¯ngertips relative to the thumb tip to mimic the operator's hand manipulation. These
conditions result in two di®erent kinematic equations as shown as follows:sl eyems eyesl thumb T ¼ ms thumb T;
sl thumb
P sl finger ¼ ms thumb P ms finger ;

ð3Þ
ð4Þ

where A P B is a 4  1 position vector of point B relative to frame A. Equations (3)and (4) imply that the polygonal chain of vectors connected to POV, thumb, andother ¯ngers is a congruence between the operator and robot.20 Figure 8 shows theschema of the congruence of vectors in the method. As long as the ¯nger opposition isreproduced correctly, the operator can see and control the robotic ¯ngers as perfectas his/her own ¯ngers. Also, to realize this, the width of ¯eld of view (FOV) between
them have to be corresponded exactly so that the camera image shoot in speci¯cvisual angle is projected on the operator's retina in the same way. In the visuoauditory information system of TELESAR VI, the angle of view of the eye-camera(See3CAM-CU135, e-con Systems) is adjusted to H : 90  =V : 50  per eye, andthe camera images are stereoscopically presented to the operator's eyes byusing a head-mounted display (Oculus CV1, Oculus Inc.) with keeping the FOV ofeye-camera. In this way, the direction of light received on the robot's camera iscorrectly reproduced on the operator's sight.

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Fig. 8. Congruence of POV to thumb/¯nger vectors between operator and robot.

4.3. Motion measurement of master operator
To realize the master-slave control of telexistence robot, the body motion measurement of the operator should be as precise as the robot control because the motion
data are used to calculate the target values of the controller. This section describes
the details of motion measurement system of the master.
4.3.1. Optical motion measurement
To obtain the operator's body motion in real time, an optical motion capturingsystem (OptiTrack, NaturalPoint, Inc.) consisting of eight cameras surrounding theoperator's whole body is employed as the measurement system. Through this system,
6DOF position and attitude data of operator's nine body-parts (head, shoulders,arms, hands, and feet) are recorded using the retrore°ective markers attached on theparts at a sampling rate of 240 Hz. These data are employed for the motion control ofslave robot's body-parts such as head and arm-endpoints. In addition, the active
marker sensor, which tracks the position using LEDs, is installed in the system, andthe markers are attached to the ¯ngertips of the operator to obtain 3DOF position
data. These data are employed for the motion control of slave robot's corresponding¯ngers in terms of the ¯ngertip position. Moreover, these data are used to learn thedata of position estimation method described later.
4.3.2. Wearable measurement device
In addition to the aforementioned motion capture system, a wearable sensor
glove (IGS-Cobra Glove 16, Synertial UK Ltd.), which is equipped with 16 inertial
measurement units (IMUs) is employed to obtain operator's ¯nger motion in detail.
This sensor glove measures 3DOF attitude data of operator's ¯nger segments at
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TELESAR VI: Telexistence Surrogate Anthropomorphic Robot VIa sampling rate of 60 Hz, and these data are employed for the motion control ofcorresponding robot ¯ngers in terms of the ¯ngertip orientation. In addition, these¯nger segment data are used to excite the estimation method described later.
4.3.3. Fingertip position estimation
To achieve natural teleoperation using telexistence robot, the motion measurementof operator should be precise and stable to reproduce the operator's body action,
particularly hand manipulation. Therefore, the measurement system is endowedwith two di®erent ¯nger measurement sensors. However, the stability of position
tracking is still insu±cient to achieve precise manipulation because of the limitationof optical measurement such as occlusion. If the ¯ngertip position of the operator islost, the ¯nger motion of the robot becomes confusing. To overcome this problem, adata complement method of ¯ngertip position is developed.21 This method is basedon the forward kinematics model of human hand, which represents the operator's¯nger motion, and the estimated position of ¯ngertip can be calculated using sensor
glove instead of motion capture system. Provided that this method needs calibrationof the internal model parameters of individual bone length. In the calibration procedure, correspondence between the ¯ngertip position and attitude of ¯nger segments are learnt in advance to estimate the internal parameters of the model.
Figure 9 shows the time series of estimated ¯ngertip positions. As shown in the ¯gure,the accuracy of the position estimation is considerably high, and the root meansquare error (RMSE) of the data is on average 5.2 mm. Note that the accuracy

Fig. 9. Estimated ¯ngertip position versus actual measurement data.

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S. Tachi, Y. Inoue & F. Kato

depends on the quality of kinematics model whose parameters are estimated from thelearning data.
4.4. Evaluation of correspondence between master-slave movement
4.4.1. Trackability of head motion
In order to keep master's POV position and direction identical with the slave's ones,
the tracking ability of head motion is important factor for telexistence robot. To
evaluate the tracking ability of head movement, the responsiveness of single-axis
rotation of 3DOF head is analyzed at ¯rst. Figure 10 shows the rotation angle foreach axis obtained when the operator shaken his head quickly without body movement and slave followed the movement. As shown these graphs, there are slight delay
between them, and the cross-correlation function was calculated to evaluate thetemporal delay for each axis. As the result, the delay in roll-, pitch-, and yaw-axis are
67 ms, 92 ms, 83 ms, respectively. These values are adequately low enough to track
the POV direction of operator's head movement without discomfort.
4.4.2. Error in head position trajectory
In addition to single-axis head rotation, to evaluate the positional accuracy of
reproduced head motion the operator's POV during the actual operation including
body movement, the cross-correlation function of head motion trajectory in 3D space
between operator and robot is analyzed. Figure 11 shows the time series of headmotions obtained when the operator repeatedly and laterally swayed his upper bodyquickly with neck motion and the robot followed the movement. Same as the result of

Fig. 10. Single-axis rotations of head motion.

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TELESAR VI: Telexistence Surrogate Anthropomorphic Robot VI

Fig. 11. Head motion trajectories of master operator and slave robot.

head rotation angles, temporal delay of the motion trajectory is observed between
them, but the cross-correlation function between them revealed that the delay wasapproximately 340 ms. This value is greater than the delay of single-axis head rotation shown above. It is because the body movement produces more inertia of upper
body in comparison to single head movement, leading large temporal delay. Notethat this quick and repeating movement examined here is an extreme example toevaluate the responsiveness of mechanical system in upper-body. In normal, the bodymoves more slowly, therefore the delay has small e®ect. Rather, the accuracy of
position is more important factor. Therefore, the positional errors at the turning
points of motion trajectory were evaluated. For twelve pairs of corresponding peaks,
the positional error was 19  8 mm. This means reproduced POV position of slave
robot is adequately accurate even though the operator moves fast.
4.4.3. Error in hand motion trajectory
Same as the head motion analysis, the reproduction accuracy of end-e®ector in 3D
space is evaluated using the cross-correlation analysis. Figure 12 shows the timeseries of hand motions obtained when the operator repeatedly and vertically shookhis right hand without any other body motion and the robot followed the movement.
Similar to the head motion results, a slight temporal delay is observed between them,and the cross-correlation function between them revealed that the delay was approximately 160 ms. This value is faster than the delay in head position, but close to
the delay in head rotation. During robot hand manipulation in telexistence, it isexpected that head position does not move so extensively whereas the head direction
does changes frequently. Therefore, the delay is appropriate. Also, positional errors
at the turning points of motion trajectory were evaluated same as head motion.
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S. Tachi, Y. Inoue & F. Kato

Fig. 12. Hand motion trajectories of master operator and slave robot.

For twelve pairs of corresponding peaks, the positional error was 59  11 mm. The
spatial divergence of hand position can lead misdirection of the vector to the ¯ngers,
and the positional error observed here is not small. However, it can be probableimproved by gain adjustment of the 7DOF arm, because the many amount of theerror comes from undershoot of vertical axis, that is less elevation of arm movement.
5. Principle of Haptic Primary Colors
To convey the same sensation felt when a person touches the surface of a physicalbody with his or her ¯nger, if it is necessary to present the same actual physical bodyto the ¯nger, the sense of touch cannot be handled as information media. In the caseof vision, even if the color of a physical body di®ers from the actual spectra, if thecone cells on the human retina responsible for human RGB ranges are in the same
proportions, the object appears to have an identical color. This very principle makes
TV, color photographs, and color prints possible. It is the principle of three primarycolors. The principle of haptic primary colors argues that the same principle holds forthe sense of touch. In other words, it assumes the existence of haptic primary colors.
One evidence for the existence of haptic primary colors is the presence of distinctlydi®erent types of sensory receptors. They include Merkel cells, Meissner's corpuscles,
Pacinian corpuscles, and Ru±ni endings. There are also free nerve endings that
respond to heat, cold, and pain. Neurophysiological research reveals that Merkel cells
and Ru±ni endings detect pressure and shearing forces, respectively, Meissner's
corpuscles detect low-frequency vibrations, and Pacinian corpuscles detect highfrequency vibrations. Furthermore, it is assumed that, when the skin comes into
contact with a physical body, Merkel cells and Ru±ni endings detect displacement,
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TELESAR VI: Telexistence Surrogate Anthropomorphic Robot VI

Meissner's corpuscles detect velocity, and Pacinian corpuscles detect acceleration at
the contact to the physical body.
Real physical bodies have many physical properties, such as concavo-convex
shape, friction, heat, and elasticity. To reproduce all these properties requires
bringing in the object itself, and it is impossible to present them through information
media. However, if we consider situations in which a cutaneous sensation arises, weknow that when a person touches an object, force, vibration, and temperature change
occur on the skin surface, which triggers responses from the aforementioned sensory
organs, giving rise to the sensation of touch. If this is the case, regardless of what thephysical properties, such as concavo-convex shape, friction, heat and elasticity, are, if
sensory receptors respond in the same manner as when the person touches thephysical body, the same sense of touch arises in him/her.
Therefore, haptic primary colors can be determined by selecting primaryvariables in the physical space based on the method equivalent to the method ofvisual perception in which RGB are the primary variables. As mentioned above,
Merkel cells and Ru±ni endings respond to pressure and shearing force, Meissner's corpuscles to low-frequency vibrations, Pacinian corpuscles to high-frequency vibrations, and free nerve endings to pain, heat and cold. Therefore, evenwhen a person is not actually touching a physical body, if the same pressure andshearing force, that is, \force" as a vector, the same \vibrations," from low to highfrequencies, and the same \temperature" as those presented on the surface of thehuman skin when touching a genuine physical body are presented, the person will
have the same sensation. Although sensations change with the active movementsof the person, we need only to track these movements to faithfully reproduce
them.
This approach is akin to the approach to visual perception, which, instead of
reproducing all spectra of light, uses only those spectra that correspond to RGB andreproduces almost all visual information based on the combination of these primaryvariables.
Thus, the current approach uses three physical quantities  force, vibration,and temperature  as primary variables, which arise when the skin surface
comes in contact with a physical body, and records and transmits their changes
over time. Subsequently, it synthesizes various sensations of touch based onthese variables, instead of reproducing all the aforementioned physical properties of the physical body. Figure 13 shows the principle of haptic primary colors
in relation to primary variables in the physical, physiological, and psychologicalspaces. 22,23
The aforementioned discussion can be summarized as follows: A target object has
physical properties, such as the concavo-convex shape, surface texture, friction,
thermal conductivity, viscosity, elasticity, inertia, and humidity. However, generally,
human cutaneous receptors only sense force (skin deformation), vibration, andtemperature change, which occur at the contact to the physical body when
the person touches the target object. Therefore, the optimal sensors are the force,
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S. Tachi, Y. Inoue & F. Kato

Fig. 13. Principle of haptic primary colors.

vibration, and temperature sensors that directly sense these quantities. These
quantities are transmitted and presented to the person through the force display,
vibration display, and temperature display. Figure 14 shows the diagram of themeasurement system, transmission, and presentation based on the principle of haptic
primary colors.
The following section provides a detailed explanation on the TELESAR VI haptictransmission system based on the principle of the haptic primary colors.

Fig. 14. Haptic sensing, transmission, and display.
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TELESAR VI: Telexistence Surrogate Anthropomorphic Robot VI

6. Haptic Telexistence for TELESAR VI
6.1. Haptic sensing system for a slave hand
A haptic sensing system, equipped with sensors for the haptic primary colors (force/
vibration/temperature),32 was developed for the hand of robot TELESAR VI. The
haptic control board was mounted on the back of the robot's hand (Figs. 15 and 16).
The haptic control board has parallel wired connections to each ¯nger-tip sensor
board using the I2C protocol. The weight of the developed slave hand is 0.562 kgf.
The haptic sensors are embedded in the ¯nger-tip structure (Fig. 17). The acceleration sensor and thermistor are soldered onto the ¯nger sensor board. The
thermistor (56A1002-C3, Alpha Technics) is connected via an analog-to-digitalconverter (ADC) module (ADS1015, 12 bit, 4 ch.). The ADC quantizes the resistance of the thermistor and transmits the voltage via I2C. The sensor board has awired connection to the ¯nger base board, along with the force-sensor connection.
The haptic information is transmitted between the ¯nger-tip base board and thehaptic control board.
To acquire the acceleration, a KX126-1063 3-DOF accelerometer was embeddedin the ¯nger-tip (the read rate/gravity range/quantum bit are 1.6 kHz/2 g/12 bit,respectively; Kionix/ROHM Semiconductor Co., Ltd.). A piezoresistance 3-DOF
force sensor (DynPick MAF-3, 1 kHz, WACOH-TECH Inc.) was used to acquire
the vertical force and the two horizontal-force component. The haptic informationfrom the ¯ve ¯ngers was transmitted to the haptic control board in parallel, using
separate I2C ports.
The measured haptic signal was transmitted to a PC through an Ethernet cable.
The waveform of the haptic information was displayed on the PC, and thenre-compounded for presentation using the haptic display on the master glove.

Fig. 15. Slave hand.
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S. Tachi, Y. Inoue & F. Kato

Fig. 16. Haptic base board.

Fig. 17. Finger-tip structure (left: engineering drawing; right: developed haptic sensors).

Figure 18 shows a diagram of the haptic signal transmission and some waveform
examples acquired by the haptic primary-color sensors.
6.2. Finger design configuration
In this section, the haptic ¯nger design is described. The haptic sensors and boards
were embedded in the ¯nger structure. A relay board was mounted on top of the¯nger base bone (Fig. 17), and the force sensor was ¯xed under the bone. The ¯nger
base bone was connected to the ¯rst knuckle joint. The middle layer bone was
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TELESAR VI: Telexistence Surrogate Anthropomorphic Robot VI

Fig. 18. Haptic signal transfer to the master glove.

bridged by the force sensor (the opposite side). The ¯nger sensor board was equipped
at the bottom of the middle layer bone. The thermistors were located on the exterior
surface of the ¯nger cover.
The lead wire of the thermistor was soldered onto the sensor board. The thermistor location acted as a type of contact sensor because several thermistors were
distributed on the ¯nger cover. The temperature °uctuation allowed the location to
detect a grabbed object on the ¯nger pad. The thermistor was ¯xed using a thin highexpansion elastic ¯lm (0.01 mm, moist healing pad, Hakujuji Co., Ltd.) on the ¯nger
cover.
Arti¯cial skin, made from elastic urethane resin and aluminum oxide powder, wasinvestigated. The aluminum oxide was expected to improve the heat conduction
to the thermistor. Figure 19 (lower) shows the skin attached to the ¯nger cover.
The trial manufactured skin was used as a telemedicine module that reproduced
the human body temperature,24 and the thermal conduction from the device improved its performance over that of rubber. Despite the good heat conduction, theproposed arti¯cial skin was much thicker (nearly 1 mm) than the thin ¯lm (0.01 mm,
Fig. 19(upper)). Second, the compounded skin was very sticky, and was covered with

Fig. 19. Ultra-thin elastic ¯lm (upper ¯nger); compounded urethane resin (lower ¯nger).
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S. Tachi, Y. Inoue & F. Kato

talc powder to reduce the stickiness. The talc powder could a®ect the robot's electronic
circuits or mechanism. Therefore, we chose thin ¯lm for the demonstration experiment.
The ¯nger-structure parts were 3D printed; the ¯nger base bone and middle layer
were printed using solid-light nylon material, and the ¯nger cover (Fig. 17) was
printed with soft silicon rubber (AGILISTA (AR-G1L), shore sti®ness 35). The soft
silicon rubber was used to enable the ¯nger to easily grab an object. The proposed¯ngers have a signi¯cantly improved grasping ability compared to the previous robot¯ngers with hard ¯nger pads.19
6.3. Haptic primary-color display for a master glove
A master glove that could present the haptic primary colors was proposed. To
display the measured haptics information, a vibro-thermal presentation module andan encounter-type force-presentation system that was driven by a thread were embedded in the glove (Fig. 20). Both modules were mounted on top of each glove¯nger. These tactile modules composed the haptic primary color texture. We introduce the force-presentation system and vibro-thermal module in Secs. 6.4–6.7.
A ¯nger-posture acquisition system (Secs. 4.3.2 and 4.3.3) comprised the masterglove (Fig. 20). Since an infrared (IR) LED marker (active-tracking type) was
mounted at each ¯nger-tip of the glove, the posture of the ¯nger end was obtained at
30 Hz using optical motion capture. Second, inertia sensors (AiQ Synertial Ltd., IGSCobraGlove16) were mounted on the glove over the phalanges, enabling them tomeasure the phalange posture.25
6.4. Force presentation by gel pad
We designed and developed a wearable deep-sensory presentation device26,27 that
stimulates deep sensation in the ¯nger joints. Figure 21 shows how a deep-sense
presentation device is attached to a ¯nger.

Fig. 20. Encounter-type haptic display mounted on the master glove.

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TELESAR VI: Telexistence Surrogate Anthropomorphic Robot VI

Fig. 21. Force presentation mechanism by sticky gel-pad and thread.

We describe our proposed haptic device that stimulates deep sensation. To apply
force, a sticky gel pad is attached to a ¯ngertip. When a thread sewn to the gel pad isdrawn by motor force, it initially deforms the ¯ngers. It then stimulates a deep
sensation inside the ¯nger joint by applying additional force. The gel pad is wornaround a ¯nger, covering the sides and the top. When a thread is pulled up, as shownin Figs. 21(b) and 21(c), the skin of the side ¯nger is also pulled up. It applies tension,
which feels like a virtual force, to the ¯nger-pad. When the force increases beyond theskin deformation range, the ¯ngertip is pulled up, stimulating a deep sensation.
Thus, a continuous force presentation, from skin deformation (tactile) to deep sensation (haptic), is enabled.
To realize the continuous-force presentation, the proposed device consists of a gelpad, a thread, a thread-passing column, and a DC motor for winding the thread.
The system con¯guration diagram is shown in Fig. 22.
The gel pad covers both sides of the ¯ngertip and the ¯ngernail without coveringthe ¯nger-pad (Fig. 21(d)). A thread is sewn to the gel pad attached to the ¯ngernail.
The other end of the thread is wound by a pulley attached to a motor, mounted
on the back of the hand. On the path to the ¯ngertips, the thread passes through2050019-23

S. Tachi, Y. Inoue & F. Kato

Fig. 22. Motor control con¯guration of the thread-driving system.

a threading column mounted on the gel pad. The threading column was designedby CAD, according to the shape of the ¯nger, and printed with nylon material.
A small DC motor (Micro Metal Geared motor, HP 6 V, gear ratio 10:1, Pololu
Robotics & Electronics)28 with back drivability was used to drive.
6.5. Force presentation to pick up the finger
We propose a ¯nger pick-up-type force-presentation system that is driven by athread. In Sec. 6.4, we described a force-presentation method using a sticky gel-pad.
It can be used to apply force from tactile (skin deformation) to deep sensation.
However, the gel-pad has some defects; for example, the stickiness decreases fromsweat, usage count, etc. Therefore, a pick-up-type force-presentation system was
proposed, with a similar mechanism.
The former mechanism has rolls to keep the adhesive between the ¯nger back andsides and the gel-pad. When the gel-pad is pulled up by the thread, it also pulls up
the sides of the ¯nger. An elastic ring in the shape of a C was used to pick up the¯nger from both sides. Figure 21(e) shows the ring placed on the ¯nger. Figure 20
lower picture shows the developed master glove.
The proposed method enables a robust application of force, despite wet or sweaty
conditions. It enables a continuous force presentation from weak (skin deformation)
to strong (deep sensation). The pick-up ring pushes both sides of the ¯nger-pad
bottom, unlike the gel-pad method, which pulls up both ¯nger sides, and expends thevirtual force on a ¯nger-pad. The ring method could conceivably improve the adhesion to both sides of the ¯nger.
6.6. System configuration
Figure 22 shows the driver board (PIC32 MM0064 GPL036). It sends a commandfrom the PC via UART (asynchronous serial communication) to control the motor.
In response to a command from the PC, the control target is obtained, the sensor
information is returned, and the motor is controlled.
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TELESAR VI: Telexistence Surrogate Anthropomorphic Robot VI

Since a magnet is attached to the pulley, the rotation can be measured. Moreover,position control is possible by controlling the rotational speed of the pulley. In
addition, both motor drivers (DRV8833, Texas Instruments) have a current-measurement function that can perform pulse-width modulation (PWM) control of up to
10.8 V and 1.5 A for two circuits. A No. 0.8 (4.8 kgf) thread thickness was used.
Because of safety considerations, the force that human ¯ngers can exert is estimatedto be about 5 kgf.
6.7. Composition of the haptic primary-colors presentation glove
By combining the vibro-thermal tactile unit (Fig. 23)29,30 with a glove (Fig. 21(d))
capable of presenting tactile force and deep sensation, it becomes possible to present
the three haptic primary colors of force, vibration, and temperature. The vibrothermal tactile unit was developed by the JST ACCEL project on \Embodied Media
Technology based on Haptic Primary Colors." A compact version of the vibrating
actuator (ForcereactorTM AF series) provided by ALPS ELECTRIC Co., Ltd. isembedded inside the device. A Peltier element (KSMH029F, KELK Ltd.)31 ismounted on the top of the device. A haptic presentation corresponding to the tactile
primary colors is possible. The weight of the developed master glove is 0.313 kgf.
6.7.1. Haptic sensor evaluation
Figure 24 shows examples of the haptic signal acquired from the proposed system.
Data from di®erent type of woven cloths (plain weave, acrylic fur, and denim) wereacquired. Acceleration (vertical), force (vertical), and temperature signals from anindex ¯nger were measured for one second. Lower right chart of Fig. 24 shows thesignal example acquired by rubbing a cucumber surface which has just been takenout from a refrigerator. When the robot ¯nger touched convex part of surface, alower temperature was measured.
The upper image of Fig. 25 shows the temperature data when the robot hand is
grabbing a glass of hot black tea. Since the thumb, middle, and ring ¯nger of theFig. 23. Vibro-thermal tactile module.
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S. Tachi, Y. Inoue & F. Kato

Fig. 24. Haptic primary color data for three cloths (plain weave, acrylic fur, and denim) and cucumber.

Fig. 25. Grabbing hot/cold black tea.

robot touched a glass with under the liquid level of the glass, rapid increases intemperature were observed for these ¯ngers. Since the thumb has more degree of
freedom and particularly ¯ts the surface of the glass, the more rapid rising in temperature was observed. Gentle temperature increase was observed for the index
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TELESAR VI: Telexistence Surrogate Anthropomorphic Robot VI¯nger, which touches the glass above the liquid level. The little ¯nger did not touch
the glass ¯rmly, so the temperature rise was fairly gradual. The lower image of
Fig. 25 shows the temperature data when the robot hand is grabbing a glass of iced
black tea. Since the thumb, index, middle and ring ¯nger of the robot touched aglass with under the liquid level of the glass, rapid decreases in temperature
were observed for these ¯ngers. Since the thumb has a high degree of freedom andparticularly ¯ts the surface of the glass, the more rapid falling in temperature wasobserved. The little ¯nger did not touch the glass ¯rmly, so the temperature fall was
fairly gradual.
6.7.2. Robustness of haptic display
The proposed haptic presentation glove is con¯gured to ¯t both large and smallhands of a wearer. The glove worn by the user has a module designed to ¯t the¯ngertip, which presents vibration and temperature (Fig. 23).30 The pick-up ring
(Fig. 20) for presenting force to the ¯ngertip has adjustability to the thickness of theuser's ¯nger. We adopted the mechanism that presents force by pulling a thread witha motor, so that the mounting position of the motor has highly °exibility. The thread
path and length from the motor to the ¯ngertips can be adjusted to accommodate
di®erent hand and ¯nger sizes. The motor can be worn not only on the back of thehand, but also on the arm. Therefore, our proposed method that can present a stable
haptic sensation regardless of the wearer's hand size.

7. Feasibility Experiments (Demonstration)
In order to show the feasibility of TELESAR VI in the real world, demonstrations
were conducted for four di®erent situations. The demonstration video33 is open to the
public.
Keyboard typing
Keyboard operation was chosen to show that all 10 ¯ngers can be used. It enables theoperator to type the keys with the same feeling as if he/she were typing with the¯nger remotely (Fig. 26).
Palpation
Palpation was chosen to demonstrate that TELESAR VI system can transmit tactile
sensations using 10 ¯ngers. There is currently an accelerated search for remote means ofhealthcare delivery in response to the new virus (COVID-19) around the world. One ofthe problems with current remote diagnosis is that it cannot convey tactile information
while it can convey audiovisual information. We demonstrated the use of palpation toprovide medical interviews/cares in such situations where direct medical treatment is a
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S. Tachi, Y. Inoue & F. Kato

Fig. 26. Typing HELLO.

Fig. 27. Tele-palpation for lymph node.

risk. It is supposed that a medical doctor touches the lymph nodes around throat andchecks the body temperature when a patient complains about throat pain (Fig. 27).
Trapping and shooting
The robot's operator can move freely while looking at the robot's legs as if they were
his own legs. As a demonstration of how the whole body coordinates including legs,
the action of trapping and shooting a ball is chosen (Fig. 28).
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TELESAR VI: Telexistence Surrogate Anthropomorphic Robot VI

Fig. 28. Trapping and shooting a ball.

Ikebana
As an example of performing delicate work using visual, auditory, and tactile
senses, a demonstration was conducted by selecting Japanese fresh °owers including
artistic aspects. Figure 29 shows the robot doing a Japanese-style °ower arrangement.
The avatar robot picked up a tulip stalk lying on a desk, moved the stalk above a tray
and put it to a water-absorbing sponge base in the tray.

Fig. 29. Ikebana-style °ower arrangement.
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S. Tachi, Y. Inoue & F. Kato

8. Conclusion
In this paper, we described a telexistence avatar system, TELESAR VI. The novelties
of TELESAR VI are as follows:(1) It is a telexistence robot which, unlike anything the world has ever seen, has
67 DOFs as an avatar, and can naturally convey and express various humanactions.
(2) All of the ten ¯ngers of the avatar robot are equipped with the force, acceleration(vibration), and temperature sensors and can faithfully transmit this haptic
information. Thus, the combined use of the haptic and visuo-auditory information actualizes the remote sense of existence as if the operator were physicallyexisting there as the avatar robot serves as a new body.
(3) It realizes novel control over ¯ngers by equalizing the vectors between the thumband other ¯ngers in the master with those in the slave, thereby enabling accurate
hand grasping.
In the future, we would like to apply this approach to remote work and telemedicine
involving bodily movements, as well as telecommunication, and remote experience,such as traveling, shopping and entertainment industries.
Acknowledgment
This work was supported by JST ACCEL Grant Number JPMJAC1404, Japan.
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2. A. Scoică, Susumu Tachi -the scientist who invented telexistence, ACM Crossroads 22(1)(2015) 61–62.
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Y. Ohta and H. Tamura, ed. (Springer-Verlag, 1999), pp. 251–260.

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10. S. Tachi, N. Kawakami, M. Inami and Y. Zaitsu, Mutual telexistence system using retrore°ective projection technology, Int. J. Humanoid Robot. 1(1) (2004) 45–64.
11. S. Tachi, N. Kawakami, H. Nii, K. Watanabe and K. Minamizawa, TELEsarPHONE:
Mutual telexistence master slave communication system based on retrore°ective projection technology, SICE J. Cont. Measure. Syst. Integrat. 1(5) (2008) 335–344.
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Reality Innovations (ISVRI 2011), Singapore, 2011, pp. 111–118.
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telexistence, in Proc. ASIAGRAPH 2007, Vol. 1, Tokyo, Japan, 2007, pp. 1–6.
14. S. Tachi, K. Watanabe, K. Takeshita, K. Minamizawa, T. Yoshida and K. Sato, Mutual
telexistence surrogate system: TELESAR4 -telexistence in real environments using
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Measurement and Control in Robotics (ISMCR2019) (Houston, USA, 2019), pp. A1-1-11–A1-1-1-4.
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Hand Manipulation, Proceedings of the 22nd International Symposium on Measurement
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27. F. Kato, Y. Inoue and S. Tachi, Haptic display glove capable of force/vibration/temperature, in Proc. 22nd Int. Symp. Measurement and Control in Robotics (ISMCR2019)(Houston, USA, 2019), pp. D2–2–1–D2–2–5.
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33. TELESAR VI, Telexistence surrogate anthropomorphic robot VI (demo movie), https://www.youtube.com/watch?v=3glmo2OftPg.

Susumu Tachi is currently Professor Emeritus of The University of Tokyo, Japan, and is leading several research projects ontelexistence, virtual reality and haptics including JST ACCEL
Embodied Media Project at Tachi Laboratory, Institute of Gerontology, The University of Tokyo. He is the Founding Presidentof the Virtual Reality Society of Japan.
Dr. Tachi received his B.E. and Ph.D. degrees from The
University of Tokyo, in 1968 and 1973, respectively. He joined theFaculty of Engineering of The University of Tokyo in 1973, and in 1975, he moved to
the Mechanical Engineering Laboratory, Ministry of International Trade and Industry, Japan, where he served as the Director of the Biorobotics Division. From1979 to 1980, Dr. Tachi was a Japanese Government Award Senior Visiting Scientist
at the Massachusetts Institute of Technology, USA. In 1989, he rejoined The University of Tokyo, and served as Professor at the Department of Information Physics
and Computing till March 2009. He served also as Professor and Director of theInternational Virtual Reality Center at Keio University, Japan from April 2009 till
March 2015. He initiated and founded International Conference on Arti¯cial Reality
and Telexistence (ICAT) in 1991 and International-collegiate Virtual Reality Contest (IVRC) in 1993. He received the 2007 IEEE VR Career Award, and served as
General Chair of IEEE Virtual Reality Conferences. https://tachilab.org/

Yasuyuki Inoue is received his Ph.D. degree in Engineeringfrom Toyohashi University of Technology, Japan in 2010.
He worked at The University of Electro-Communication (2011–2014), Mie University (2014–2015), The University of Tokyo(2015–2020). Currently, Project Assistant Professor of Toyohashi
University of Technology, Japan. The ¯eld of expertise are
cognitive psychology, human informatics and Virtual Reality.
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TELESAR VI: Telexistence Surrogate Anthropomorphic Robot VI

Fumihiro Kato is currently Project Researcher of The
University of Tokyo, Japan, and is belonging to JST ACCEL
Embodied Media Project at Tachi Laboratory, Institute of Gerontology, The University of Tokyo. He received his B.E. and M.E.
from the University of Electro-Communications in 2008 and 2010.
He also received Ph.D. degree in Department of Computational
Intelligent and System Science from Tokyo Institute of Technology 2016, and a JSPS research fellow for young scientists since2010. He worked at TOSHIBA R&D from 2014 to 2016 as permanent researcher. His
research interests include virtual reality, haptics, telexistence, physical simulation.
He received a Super Creator Youth Award from Information Promotion Agency ofJapan government in 2008, and Miura Prize from the Japan Society of MechanicalEngineering in 2010.

2050019-33