2012 IEEE/RSJ International Conference onIntelligent Robots and Systems
October 7-12, 2012. Vilamoura, Algarve, Portugal

Telexistence — from 1980 to 2012
S. Tachi, Member, IEEE, K. Minamizawa, Member, IEEE, M. Furukawa, Member, IEEE,and C. L. Fernando, Member, IEEE
Abstract—Telexistence technology enables a highly realistic
sensation of existence in a remote place without any actualtravel. The concept was originally proposed by the first author
in 1980, and its feasibility has been demonstrated through theconstruction of alter-ego robot systems such as TELESAR &TELESAR V, which were developed under the national large
scale project on “Robots in Hazardous Environments” and the“CREST Haptic Telexistence Project.” A mutual telexistencesystem, such as TELESAR II & IV, capable of generating thesensation of being in a remote place in local space using a
combination of an alter-ego robot and retro-reflective
projection technology (RPT), has been developed, and thefeasibility of mutual telexistence has been demonstrated.
Thirty-two years of telexistence development are historicallyreviewed in this jubilee video.

INTRODUCTION
Telexistence is a fundamental concept that refers to thegeneral technology that allows a human being to experience areal-time sensation of being in a place other than his/her
actual location and to interact with the remote environment,
which may be real, virtual, or a combination of both [1]. It
also refers to an advanced type of teleoperation system thatallows an operator at the controls to perform remote tasks
dexterously with the feeling of being in a surrogate robot
working in a remote environment. Telexistence in the realenvironment through a virtual environment is also possible.
Sutherland [2] proposed the first head-mounted display
system, which led to the birth of virtual reality in the late1980s. This was the same concept as telexistence incomputer-generated virtual environments. However, it did
not include the concept of telexistence in real remoteenvironments. The concept of providing an operator with anatural sensation of existence in order to facilitate dexterous
remote robotic manipulation tasks was called "telepresence"by Minsky [3] and "telexistence" by Tachi [4]. Telepresence
and telexistence are very similar concepts proposed
independently in the USA and in Japan, respectively.
However, telepresence does not include telexistence in virtualenvironments or telexistence in a real environment through avirtual environment.
The concept of telexistence was proposed by the firstauthor in 1980 [4], and it was the fundamental principle ofthe eight-year Japanese national large scale “Advanced Robot
Technology in Hazardous Environment” project, whichbegan in 1983, together with the concept of “Third
Generation Robotics.” The theoretical consideration andsystematic design procedure of telexistence were establishedthrough the project. An experimental hardware telexistence
The authors are all with Keio University, Hiyoshi, Yokohama223-8526, Japan (Phone: +81 45-564-2499; fax: +81-45-564-2549;
e-mail: tachi, kouta, m.furukawa, charith@ tachilab.org).

978-1-4673-1735-1/12/S31.00 ©2012 IEEEsystem was developed and the feasibility of the concept wasdemonstrated.
In this jubilee video, the development of telexistence
technology and telexistence systems is historically reviewed
from 1980 to 2012.
HISTORY OF TELEXISTENCE
A. How Telexistence was Conceptualized and Developed
Our first report [5,6] proposed the principle of atelexistence sensory display and explicitly defined its design
procedure. The feasibility of a visual display providing asensation of existence was demonstrated throughpsychophysical measurements performed using anexperimental visual telexistence apparatus.
In 1985, a method was also proposed for developing amobile telexistence system that can be driven remotely withboth auditory and visual existence sensations. A prototype
mobile televehicle system was constructed and the feasibilityof the method was evaluated [7].
B. Telexistence Manipulation System: TELESAR
The first prototype telexistence master-slave system for
performing remote manipulation experiments was designed
and developed, and a preliminary telexistence evaluation
experiment was conducted [7-10]. The slave robot employs
an impedance control mechanism for contact tasks. An
experimental block-building operation was successfully
conducted using a humanoid robot called TELESAR(TELExistence
Surrogate
Anthropomorphic
Robot).	 
Experimental studies of the tracking tasks quantitatively
demonstrated that a human can telexist in a remoteenvironment through a dedicated telexistence master-slave
system [8]. An experimental operation was successfully
conducted in an environment with poor visibility using
TELESAR and its virtual dual [11].
Based on the technology, telexistence into a humanoid
biped robot was realized in 2000 under the “Humanoid RobotProject” (HRP) [12].
C. Mutual Telexistence: TELESAR II & IV
A method for mutual telexistence based on the projectionof real-time images of the operator onto a surrogate robot
using retroreflective projection technology (RPT) was first
proposed in 1999, and the feasibility of this concept wasdemonstrated by the construction of experimental mutualtelexistence systems using RPT in 2004 [13].
In 2005, a mutual telexistence master-slave system called
TELESAR II was constructed for the Aichi World Exposition.
Nonverbal communication actions such as gestures andhandshakes could be performed in addition to conventionalverbal communication because a master-slave manipulation
robot was used as the surrogate for a human [14]. Moreover,5440

a person who remotely visited the surrogate robot’s location
could be seen naturally and simultaneously by several people
standing around the surrogate robot.
The mobile mutual telexistence system, TELESAR IV,
which is equipped with master-slave manipulation capability
and an immersive omnidirectional autostereoscopic 3D
display with a 360° field of view, was developed in 2010 [15].
TELESAR IV is constructed from an immersive audiovisualsystem, TWISTER—an omnidirectionally mobile robot witha robot arm and hand—and projection of the remoteparticipant’s image on the robot by RPT.
Face-to-face communication was also confirmed, as local
participants at the event were able to see the remoteparticipant’s face and expressions in real time. It was further
confirmed that the system allowed the remote participant to
not only move freely about the venue by means of thesurrogate robot, but also perform some manipulation tasks
such as a handshake and several gestures.
TELEXISTENCE AVATAR: TELESAR V
In telexistence, an operator can feel his/her slave robot as
an expansion of his/her bodily consciousness and has theability to move freely and control the slave robot in a similar
way to his/her body movement.
In order to certify this concept in telexistence, the TORSO(TELESAR III) system, which can acquire visual information
in a more natural and comfortable manner by accurately
tracking a person’s head motion with 6 DOF, wasconstructed [16]. TELESAR V, a master-slave robot systemwith a conjunction of 53 DOF for performing full-bodymovements, was developed in 2011. In addition, an operator
can feel the fingertip haptic and thermal sensations whentouching objects remotely. The TELESAR V system satisfies
the following functions [17,18].
(1) The operator can freely and independently move his/herhead, upper body, and both arms and hands. In contrast, theslave robot’s arms and hands follow similar movements with53 DOF while maintaining 6-DOF arm endpoint accuracy.
(2) The operator can have a clear wide-angle stereo view of
the remote site with 6-DOF point-of-view robot visionaccuracy. The operator also has the ability to performbinaural, bi-directional verbal communication. (3) The
operator can grasp and manipulate objects in a similarmanner to a human hand. (4) The operator feels fingertip
haptic and thermal sensations when touching objects
remotely.
CONCLUSION
Telexistence is a concept that allows humans to be
emancipated from time and space restrictions and to bepresent at a “location” defined by inconsistent time andspace or in a virtual space. Telexistence technology washistorically reviewed over the period from 1980 to 2012.
ACKNOWLEDGMENT
This study on TELEXISTENCE was conducted in collaboration withmany former and current students, affiliates, and staff members of the Tachi

Laboratory at the University of Tokyo and Keio University, including H.
Arai, T. Maeda, Y. Inoue, K. Yasuda, T. Sakaki, E. Oyama, Y. Yanagida, N,Kawakami, I. Kawabuchi, M. Inami, D. Sekiguchi, H. Kajimoto, H. Nii, Y.
Zaitsu, Y. Asahara, K. Sogen, S. Nakagawara, R. Tadakuma, K. Watanabe,K. Sato, S. Kamuro, T. Kurogi, K. Hirota, and M. Nakayama.
This work is partly supported by JST-CREST and the authors declare
under their sole responsibility that the experimental protocol was compliant
with International Ethics regulations.
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