Development of an intelligent Container Prototype
for a Logistical Support Robot System in Living Space
Rui FUKUI, Masayuki SHODAI, Taketoshi MORI, Tomomasa SATO.
Graduate School of Information Science and Technology, The University of Tokyo
This paper reports development of an intelligent container,
a unit of the logistical support robot system in living space.
The container not only supports human to fix and arrange
their commodities, but also supports robots to achieve their
logistical tasks. In other words, the intelligent container is a
mediator between human’s request and robots’ capabilities.
The container has four major roles in our logistical support
system. (1) Taking several commodities in and recognizing
and acquiring contents’ information. (2) Supporting human
and robots to transfer the container. (3) Receiving users’
command as a simple user-interface. (4) Communicating to
a host computer and informs the contents of the container
and users’ command. To realize those roles, the container
is equipped with a grasping navigation mechanism for robot
handling, RFID reader for the recognition of contents, and
LCD device to display supporting information to human and
robot. Finally, a primary function is evaluated in experiment
to confirm that an acceleration sensor enables the container
to detect being transferred by human.
In the future, the intelligent container will play a role of
contact point for human and robots in our target system, that
enables human-robot symbiotic life.
Facing problems with aging population combined with
diminishing number of children, people become to expect
robots to support their daily life. To this end, Intelligent
Cooperative Laboratory at the Univ. of Tokyo are developing
“a logistical support robot system in living space” as Fig.1
shows. The system is an environmental robot (i.e. intelligent
environment) that daily supports our access to commodities.
As commodities, we suppose books, magazines, CDs, preser-
vative foods, grocery stock and so on. The system consists
of four sub-systems, (1)intelligent containers for human to
place commodities, (2)a ceiling mobile robot to transfer
the containers, (3)shelf type (or upper ceiling) rack system
and (4)a stacker crane robot to take out and put in containers
from the rack system.
There are two kinds of advantages in the system. The
first ones are advantages in robotic (physical) support and
the other ones are advantages in informative support. In
robotic or physical support, upper ceiling rack system and
ceiling mobile robot achieve space saving, i.e. people cannot
use the upper ceiling space efficiently until now, but these
systems enable people to use it with no special care. In
addition, robots need to deal with only the containers (not
(3b) Shelf type
(3a) Upper ceiling
Fig. 1. Conceptual sketch of the logistical support robot system
commodities themselves). Thus the mission can be easier
and more practical for robot than dealing with complex
While in informative support, if the intelligent container
can acquire a log of commodities’ use, we can obtain never
lost memories of commodities’ arrangement, i.e. the system
will remind you, when and where you fixed a thing. Further-
more, high level fixing (arrangement) of daily commodities
must be possible. By data-mining the log, the system can
sort things whether frequently used ones or not. The system
may arrange the frequently used tools at shelf type rack, and
rare used objects at upper ceiling rack.
To realize such advantages, the intelligent container plays
a significant role of contact point for human and robots in
the system, i.e. the container not only supports robots to
complete tasks, but also supports humans to enrich their life.
The framework of this paper is as follows; Firstly, in sec-
tion II, related researches are listed. Secondly, in section III,
required functions of the intelligent container are discussed.
Thirdly, in section IV, implementations of required functions
are explained. Finally, section VI is the conclusion.
II. RELATED RESEARCHES
From 1990’s to now, there were several works that tried
to make a robot system for office/home logistics. Prassler
et al. and Cosma et al. constructed a mobile robot
system for office or indoor logistics. In the paper, Prassler
concluded that “No single method suffices for solving any of
these (variety of the conditions and objectives) problems”.
(1) Taking several
(2) Supporting human
and robot to transfer
(3) Simple user-interface.
(4) Communication to the
Fig. 2. Four major roles of the intelligent container
He also described the importance of an equipment with
an array of methods. Whitney pointed that real world
is not so simple for robot, so robot control with passive
compliance is essential to handle some complicated objects.
Passive compliance is a significant factor for robot to achieve
real application. Thus the intelligent container is designed to
perform a compliant element in our complex living space.
In another topic, there are many intelligent environment
researches that aim to achieve real task in our daily life by
supporting robots with some environmental utilities; Chong
et al. constructed a knowledge network for robot with
RFID tags. In the network, robot can obtain some infor-
mation that is essential to achieve their object handling
task. On the other hands, Katsuki et al. adopted a visual
marker to let robots know the strategy of handling. These two
researches aim to support robots only in informative area,
contrary to this the intelligent container intends to support
them in not only informative but also physical area.
III. REQUIRED FUNCTIONS OF THE INTELLIGENT
The functions required for the intelligent container will be
discussed in this section. The container has four major roles
as shown in Fig. 2.
(A)Taking several commodities in and recognizing and
acquiring the contents’ information (ex. log of use)
(B)Supporting human and robots to transfer the con-
(C)Receiving users’ command as a simple user-
(D)Communicating to the host computer and informs
the contents of the container and users’ command
In the next subsections, the specifications of each role are
described in detail.
A. The specification required for the taking objects in
To accomplish taking objects in the container, we deter-
mined the following three functions.
• Object stocking function
The container should stock 5[kg] contents at max.
• Object tag recognition function
The container should be able to read and understand
RFID tag information of the contents.
• Load measuring function
To avoid over-load for robots, the container must be
able to sense the weight of contents.
B. The specification required for supporting human and
robot to transfer container
To realize transferring the container by human and robots,
the following six required functions are determined.
• Easy carrying function for human
The container should have shape and structure suitable
for human to carry easily.
• Carry sensing function
The container should sense transferring by human, so
that the system can know the necessity of updating the
container position information.
• Container stackable function
Like as a general container case, the intelligent con-
tainer should be stackable for the space saving, i.e. user
can put a container on another container.
• Container position measurement support function
The ceiling mobile robot must measure the position of
containers to achieve a transferring task. The container
should support robots to realize high accuracy measure-
• Grasping support function for robot
The container should have a structure for supporting the
robots’ task of grasping container.
• Surface condition recognition function
A surface condition (ex. flat or rough) where the con-
tainer is settled, is important for handling the container
by robots. Therefore the container must sense its con-
• Stacker crane support function
The container should have a mechanism to support the
stacker crane’s transporting tasks.
C. The specification required for user-interface
Two functions are required for the simple user-interface
on the intelligent container.
• Users’ command receive function
As a ubiquitous device, the container should receive
several simple users’ command.
• Service information displaying function
The container should be able to display the contents and
D. The specification required for the communication with
the host computer
The host PC has two main roles. The first one is to make
a log of containers’ state(position, contents etc...) and set up
the look-up table of logs for contents’ searching by user. The
other one is to receive and recognize the user’s request and
send commands to each sub-systems.
For these roles, two functions are required for the con-
• Internal condition report function
Periodically, the container should report internal state
changes (ex. contents change, transferred by human).
• User command transmit function
The container must inform the host computer of the user
command input as soon as possible.
IV. IMPLEMENTATION OF INTELLIGENT CONTAINER
Joint Pin for Robots
for User Interface
Fig. 3. Overview of intelligent container prototype
This section describes the implementation of the intelligent
container prototype to realize required functions discussed
in section III. Fig.3 shows the overview of the intelligent
container prototype. While Fig.4 displays the upper view
of container without a loading plate. Fig.5 indicates the
block diagram of the intelligent container system. In the next
subsections, the implementation of each functions will be
explained in detail.
Fig. 4.Upper view of the intelligent container without a loading plate.
Micro Switches for
Surface Condition Recognition
to Detect Carrying [KXM-52]
Pressure Sense Rubber
[Inastomaor SP-12] * 4
Communication Module [ZEAL]
Intelligent Container Main Frame
Robot Joint Pin and Cover * 4
Push Switch for U.I.
Flat Stand Bar * 2 Hole for Stacking * 4
Handle for Human
Fig. 5.The block diagram of the intelligent container
A. Implementation of object stocking function
First of all, the size (volume) of the container will be
discussed. Some container cases in the market have almost
the same size of A4 paper. The intelligent container refers
the size of those market products, and is set to W:250, D:350,
H:170[mm] as Fig.6 shows. Secondly the basic structure will
be considered. Almost all mass product container cases are
made by plastic injection modeling, because it can construct
ribs easily. Consequently the structure can be not only rigid
but also light weight. However the injection method is not
suitable for prototype. So in this trial production, the main
frame is produced by bending a aluminum sheet and the four
corner join parts are made by machining plastic poles. The
bottom of the main frame is removed and two plastic plates
are settled for the RFID antenna communication, i.e. RFID
cannot communicate when it’s too near metal.
Fig. 6. Abstract of the container size
Fig. 7. Main frame structure
B. Implementation of object tag recognition function and
measuring load function
Firstly, RFID tag reader and antenna are essential to read
the RFID tags attached to commodities. In this prototype,
market products of the RFID reader (TR3-C201, produced
by Takaya Corp.) as shown Fig.8 are adopted for cost and
time reduction. On the other hand, since an antenna decides
the size and shape of communication area, we tried to
produce the antenna by ourselves. The layout of the antenna
is required to communicate with all tags on the container
with no error. To realize this request, the Takaya corp.’s
antenna product (TR-A101) is referred , because the TR-
A101 can communicate with a tag in the condition that
the tag is 180[mm] far from the antenna. Secondly, four
load sensors are placed at the bottom of the container to
measure the contents’ weight. The container has double
bottom plates, and the sensors are settled on the lower plate.
The upper bottom plate is made of plastic to ensure the
RFID communication. Four RFID antenna coils are placed
under the upper bottom plate as Fig.9 shows. As load sensor,
strain gage or load cell is used generally. But amp circuit is
essential to measure small strain, and they are expensive.
In our usage, the load sensor should only has the potential
to distinguish overload or not, so we adopt much simple
rubber load sensor (SP-12, produced by Inaba Rubber Corp.)
that can sense load but non-linearly. Four rubber sensors are
settled at the bottom corners of the container as Fig.10 shows.
Fig. 8. RFID reader TR3-C201Fig. 9.The upper bottom plate
Fig. 10.Rubber sensors at cornersFig. 11. Acceleration sensor
C. Implementation of carry sensing function
There are three ways to recognize the human to carry
a container; (1)A method to measure the position of the
container. (2)A method to measure the inclination of the
container. (3)A method to measure the vibration of the
container. Among these three methods, the third method that
measures vibration is the easiest way, because the vibration
(acceleration) sensor becomes much cheaper by the progress
of MEMS technology in these days. In this research, a three-
axis acceleration sensor “KXM-53” (Fig.11) is adopted and
settled at the bottom of the container. When the acceleration
exceeds threshold, the container is recognized to be carried.
In general, an acceleration sensor can detect the gravity ac-
celeration 9.8[G], so when a user declines the container, the
sensor can detect the incline of the container subsequently.
D. Implementation of grasping support function for robot
Human eye and hand can recognize and handle compli-
cated shape of objects by utilizing their flexible knowledge.
But so far robots have not yet achieved such complex object
recognition and handling. Therefore the intelligent container
should not require robots complex procedure in handling
objects. In this research, we adopted an approach that the
container has an easy structure or mechanism for grasping
by robots. There thought to be several ways to realize this
approach, for example a method using magnet, fork insert
method and so on. In this prototype, we utilize pin and hole
joint method as shown in Fig.12. For this method, four pins
are implemented on the top of corner poles, and guard covers
for safety are attached around the pins. Fig.13 shows the pin
and the cover at one corner.
E. Implementation of container position measurement sup-
port function, users’ command receive function and service
information displaying function
Firstly, for realizing these functions LCD device was
adopted, because the LCD has the potential to become
the marker for the container position measurement and of
Fig. 12. Pin and hole joint method
Cover for Safety
Fig. 13.Joint pin and its cover
course the device for displaying information to users. In
this prototype, a LCD device on the market ”ITC-2432-
035” (produced by Integral Electronics Corp.) was utilized.
This is 3.5 inch TFT LCD device, that has 320×240 pixels’
resolution. The characteristics of the device are (1) the device
has font data in itself, (2) the device can display an image
data that is stored in a compact flash media. From these
characteristics, some simple micro controllers can display
complex text and image data.
Secondly for realizing user-interface, push switches are im-
plemented at the side of LCD device. These push switches
and LCD compose user-interface for command selection.
For simple usage, only four push switches (OK, NG, Up,
Down) are adopted. As Fig.14 shows, several use-interface
displays are implemented. Fig.15 shows the implemented
Command Input View Contents Information Display Communication State View
Transfer this container.
0F 01 22 BC 10 22
Taisyo Milk Factory.
Stock in the refrigerator.
Fig. 14. Contents of the LCD display
switched for UI
LCD device and push
Fig. 16. Handle for human
F. Implementation of easy carrying function for human and
container stackable function
A simple handle parts can realize easy carrying function
like general container case. The main frame sheet metal has
only 2[mm] thick, so plastic parts are used as handles. Fig.16
shows the handle part. To realize the container stackable
function, we utilize joint pins for robot grasping. As Fig.17
shows, a hole for inserting the joint pin is prepared at the
bottom of each corner pole. By inserting the holes on pins,
user can put a container on another container.
Hole for Inserting
Fig. 17. A hole for inserting pin
G. Implementation of stacker crane support function and
surface condition recognition function
Stacker crane will transfer containers by sustaining the
bottom of containers like a fork lift. Therefore the container
has space under the bottom of the container for inserting
forks. To make such space, two plastic stand bars are
implemented under the container that make the container
20[mm] up to floor. Fig.18 shows the bottom of the container.
The stand bars are made of low friction plastic that make
it easy to pulling containers from a rack. In addition, for
realizing surface condition recognition function, a micro
switch is settled at the center of the stand bar as Fig.19
shows. When the switch is “ON”, the surface where the
container is placed may be flat and has sufficient stiffness
to sustain the container.
the bottom of container
H. Implementation of internal condition report function and
user command transmit function
Since the host computer must communicate with sev-
eral different containers, the intelligent container should
adopt a wireless multi-communication method. To this end,
this research utilizes Bluetooth wireless communication. A
Bluetooth communication module “ZEAL” (produced by
AD Technology Corp.) is implemented on the intelligent
Flat stand bars (white) atFig. 19.
of a bar
Micro switch at the center
I. Implementation of system control circuit
As a main CPU, a micro controller “H8-3052F” (produced
by Renesas technology Corp.) is selected and mother board
is implemented like Fig.20 shows. As a power source, five
Ni-MH batteries are utilized. But the batteries can supply the
power of the container during only a few ours, so the energy
save mode is installed to make the operating time long.
V. EVALUATION TEST OF PRIMARY FUNCTIONS
This section describes evaluation tests of object tag recog-
nition function and sensing function of carrying.
Fig. 20. System control circuit
A. Evaluation test of object tag recognition function
This test examines communication distance between RFID
antenna and a tag. The communication distance depends on
the installation location and incline of tags and so on, so it’s
difficult to evaluate with generality. In this test, the maximum
communication distance at best effort is evaluated. Fig.21
shows the RFID tag for this test. The size of tag is 45 × 45
[mm], so it can be installed to a lot kind of commodities.
In the test procedure, a tag is moved down vertically from
Fig. 21. Sample of RFID tag (Right: size AA battery)
the top of container, and the first point where the antenna
can communicate with the tag is defined to be a maximum
communication point. The distance between the maximum
communication point and the antenna plate is measured
as the maximum communication distance. Fig.22-(1) shows
measured points and the maximum communication distance
at each points. The figure shows that some points can almost
cover the depth of container (150[mm]), but some points
on the boundary of multiple antennas cannot satisfy the
required specification. To reduce an effect of inter-influence
of multiple antennas, only one antenna module is activated
and maximum distance is examined. Fig.22-(2) shows the
result. Since there is no major change from the result of
multiple antennas, the effect of inter-influence of multiple
antennas is not dominant in this case.
To evaluate a relation between antenna size and communi-
cation distance, three different type antennas are produced
for trial. Fig.23 shows the overview of antenna prototypes.
According to “RFID Handbook”, the communication dis-
tance is almost the same as the radius of antenna, that means
the larger radius of antenna is the longer communication dis-
tance will be. But too large radius of antenna makes energy
transfer invalid and makes it difficult to tune a resonance
frequency, because it needs a too small size capacitor. In